Rodent phylogenetic tree

There are only 7 extant species of anomalures, with 3 genera and 9 taxa categorized by 2 subfamilies, Zenkerellinae and Anomalurinae. These anomalures, or scaly-tailed flying squirrels, are thought to have originated in the Oligocene, although the oldest known fossil record is dated back to the middle Eocene. At that time, these rodents had a widespread South Asian-North African distribution, whereas extant species are now limited to central Africa.

Anomalures can be differentiated from their flying-squirrel counterparts in Sciuridae by noting important cranial distinctions, such as their greatly reduced postorbital process, the lack of a zygomatic plate, a large and oval-shaped infraorbital canal, and various dental differences. Within the genera Anomalurus and Idiurus, a gliding membrane extending from the wrist to the ankle is found on each side of the body. This is known as a plagiopatagium, and is also found within the family Sciuridae, however the presence of a cartilaginous extension at the elbow-region of anomalures contrasts the thin cartilaginous spur found in the wrist region of species within Sciuridae. This extension aids in support when gliding from tree to tree. The ‘scaly-tailed’ distinguisher comes from 2 rows of 6-9 overlapping, pointed scales at the base of the tail that aid in grip when climbing. Anomalures are primarily vegetarian, and very little is known about their habitat requirements, communication, breeding habits, and movement style. They have little interaction with humans and are not considered threatened. Deforestation within their range and bushmeat trade should be monitored as these are their largest threats.

Author: Carson Hood

The Family Pedetidae is comprised of large rodents known as springhares. The family consists of four genera, three of which are now extinct. The only extant genera, Pedetes, persist with two known species: Pedetes surdaster, the East African Spring-hare and Pedetes capensis, the Springhare or Springhaas. Both species are found in the southern region of Africa. Pedetes capensis can be found from the southern tip of the African continent to the southern region of the Democratic Republic of Congo, while Pedetes surdaster is found primarily throughout Tanzania and southern Kenya. Fossil evidence shows the family origins began in the Miocene while the current extant genera have origins in the Pliocene. Their preferred habitat is grasslands with sandy soil suitable for burrowing. They often are seen at night foraging in groups of varying sizes, feeding on grasses, forbs, and other vegetation. Their tendency to forage on agriculture products has made them a nuisance, but they are also a valuable source of meat. Although they have been endangered in past years, protected regions have helped to secure their numbers throughout Africa.

The primary source of movement in the Pedetidae is hopping on their hind legs called ricochetal locomotion. Although they primarily hop, springhares will also use their front legs for walking. The short front legs, long hind legs, and a long bushy tail make the springhare similar to the kangaroo. The fur is thin, brownish red, with the tip of the tail being black. They have short heads, muscular necks, and large skulls that house long ears and big eyes. Interestingly, the tragus of their long ears can close the ear canal while burrowing. The front legs are built for burrowing with five long claws, while the hind legs are suited for rapid movement having four wide claws.

Work Cited
Jackson, A. 2000. “Pedetes capensis” (On-line), Animal Diversity Web. Accessed February 06, 2015 at https://animaldiversity.org/accounts/Pedetes_capensis/
Butynski, T.M. & De Jong, Y. 2008. Pedetes surdaster. The IUCN Red List of Threatened Species. Version 2014.3. . Downloaded on 06 February 2015.
Author: Edward Peebles

The family Geomyidae has been established as being closely related to the family Heteromyidae, with both of these families being included in the superfamily Geomyidaea. Fossil record evidence has placed the separation of Geomyidae and Heteromyidae into two distinct families in the early Oligocene. The large number of recognizable taxa within this family is likely due to their small population size and tendency to specialize. This family is made up of 6 different genera, and 40 different species. The family Geomyidae is commonly referred to as the “pocket gophers.” This name comes from the distinguishing fur-lined cheek pouches of this group. These pouches are used for food transport, and they extend from the side of the mouth into the shoulders. Notable species include Geomys bursarius, the plains pocket gopher.

Geoymids are found only in North and Central America. They are a fossorial group, meaning they live most of their lives underground. Their bodies are highly modified to fit this lifestyle, including short but powerful legs and claws on the forefeet. The skull is robust and angular in overall appearance, which is a trait that helps to distinguish the group from the heteromyids. These animals can move both forwards and backwards with equal ease, and it is thought that their short tails can provide important sensory information that aids with this movement. Geomyids have small eyes and ears, and an enlarged lacrimal gland that is believed to provide fluids to wash out dirt. The lips of geomyids are also adapted to burrowing, as they can be closed behind the incisors in order to allow the incisors to be used to dig without filling the mouth with dirt. The teeth of this group are ever-growing.

Geomyids are active burrowers, creating different tunnels for different purposes. Their burrow systems include long, shallow tunnels that are used for foraging, and deeper tunnels used for nesting and food storage, as well as for latrines. These burrows are important to the surrounding ecosystem, as they are used by a variety of other species. Geomyids are generally solitary animals, and they come together solely to reproduce. They eat primarily tubers and roots, and consume an incredible amount of plants.

Work Cited
Myers, P. 2001. “Geomyidae” (On-line), Animal Diversity Web. Accessed December 14, 2014 at https://animaldiversity.org/accounts/Geomyidae/
“Pocket Gophers (Family Geomyidae).” Pocket Gophers (Family Geomyidae). Web. 15 Dec. 2014. <https://kufs.ku.edu/libres/mammals_of_kansas/geomys-burs.html>.

Author: Lauren Naylor

The family Heteromyidae has been established as being closely related to the family Geomyidae, with both of these families being included in the superfamily Geomyidaea. Fossil record evidence has placed the separation of Geomyidae and Heteromyidae into two distinct families in the early Oligocene. Heteromyids are thought to have originated in the Oligocene in Western North America. The lineages later diversified within the Neogene. Members of Heteromyidae are primarily deciduous thorn-scrub and arid-adapted rodents of medium to small size. This family is made up of 60 species that are placed into 3 subfamilies and 6 genera, which are divided as follows: Perognathinae, containing Chaetodipus and Perognathus , Heteromyinae containing Heteromy and Liomys, and finally Dipodomyinae containing Dipodomys and Microdipodops, Notable species within this family include kangaroo rats and pocket mice.

Heteromyids range from western North American, down through Mexico and Central American and into northwestern South America. Many species live in deserts and dry grasslands, although members of Heteromys and Liomys can be found in both wet and dry tropical forests. All members of this family have a large, fur lined pouch in their cheek. It opens next to the mouth and extends back along the shoulders. This pouch is used for food storage. Heteromyids feed on seeds and plant parts, and sometimes animal matter. They can store this food in their cheek pouch as a way of transporting it back to their burrow. Most heteromyids burrow, and can form complex tunnel systems that are made up of multiple chambers and openings. The overall skeletal structure of the skull of a heteromyid can vary between species, but as a whole they have thin and papery skulls with underdeveloped ridges and crests. This feature helps to distinguish them from their relatives the geomyids, who all have robust skulls. Heteromyids are sciuromorphus and sciurognathus, and their cheek teeth are hyposodont. In all but the kangaroo rats, however, their teeth are not evergrowing. In most other aspects, such as pelage texture and color, the specific characteristics vary between species.

Work Cited
Alexander, Lois F., and Brett R. Riddle. “Phylogenetics Of The New World Rodent Family Heteromyidae.” Journal of Mammalogy 86.2 (2005): 366-79. Web. 21 Nov. 2014. <https://faculty.unlv.edu/riddle/pdf/Alexander_Riddle_2005.pdf>.
Myers, P. 2001. “Heteromyidae” (Online), Animal Diversity Web. Accessed November 21, 2014 at https://animaldiversity.ummz.umich.edu/accounts/Heteromyidae/

Author: Lauren Naylor

The family Castoridae includes all modern beavers and their fossil relatives. There is only one genus, Castor, and two species within this genus. These two species are Castor fiber, the European beaver and Castor canadensis, the North American Beaver. The geologic record of this family extends back to the Oligocene, with Castoroides and Palaeocastor being well known extinct members. Members of Castoridae occupy the northern temperate zone, where they serve an important ecological role. They often fell trees due to their feeding on bark and leaves, and their preferences for certain tree types have an impact on the tree species composition in the surrounding area. The building of dams, digging of canals and borrows also modifies the streams and lakes that they occupy. The resulting flooding creates habitats for various different species of wildlife.

Castorids live in small family groups, and mark specific territories with scent mounds. When frightened, they loudly slap the water with their tails as a warning to their family and as a method of startling any potential predator. They are semiaquatic, and use a pelage of long guard hairs and dense underfur for insulation. This coat has made them a target for fur trappers in the past. To aid with their locomotion in water they have a flattened tail and webbed hind feet. Their eyes are protected by nictating membrane, and their nostrils and ears can be closed as well. An interesting characteristic of castorids is that their epiglottis lies above the soft palate in the narial passage. This allows air to flow through without actually entering the mouth cavity. The back of the tongue can rise up to fit against the palate to block the passage of water from the mouth. This characteristic allows castorids to open their mouth underwater to gnaw or carry branches.

Work Cited
Myers, P. 2000. “Castoridae” (On-line), Animal Diversity Web. Accessed October 20, 2014 at https://animaldiversity.ummz.umich.edu/accounts/Castoridae/

Author: Lauren Naylor

Ctenodactylidae is a family of four genera and five species, all from the desert habitats of the Palearctic and Afrotropical regions. These medium-sized rodents are all characterized by large eyes and short legs, tails, and long whiskers. Ctenodactylidae in Greek translates to comb-toes, and refers to the bristles on the middle digits and hindfeet used to scratch. Although all living Ctenodactylines are from Africa, cladistic analyses show that their ancestry is from Asia, an example of rodents’ long-distance dispersal.

Species under this family are around the size of a domestic guinea pig, with the Desert Gundi being the smallest and the Common Gundi being the largest species. All species have a small and compact body size, covered with dense fur and short but sharp claws. Since they live in desert regions, they have a large auditory bullae to help them hear the low-frequency sounds of predators. While most rodents are nocturnal, gundis differ by being diurnal, which means they are awake during the day. Gundis do not live in burrows, and instead find shelter in fallen rocks, avoiding the heat from the sun during the summer. A usual day for a gundi includes warming up by sunbathing in the morning, foraging for food, and resting in the shade of rocks. When not in the breeding season, gundis are typically non-aggressive, and huddle together to keep warm during the winter. Being herbivores, their diet consists of leaves, flowers, and seeds. Instead of storing food, they are known to forage for food in the early mornings. They also receive all the water they need through the ingesting of plants.

To communicate, gundis use vocal, non vocal (foot drumming), and olfactory methods. The low-frequency of their calls make it hard for them to be found by predators, and calls vary by species. The Mzab Gundi is the quietest species, with a “chirp-chuckle-chirp” call. The Felou Gundi is the loudest species, repeatedly calling “chee-chee-chee” calls that can last up to an hour long. Gundis are able to start breeding at seven to nine months and have a gestation period of around two months. An average litter includes two babies, and they are born fully furred and with open eyes. The breeding behavior varies by species. Male Common Gundis live with several females, while female Desert and Mzab Gundi are solitaire. 

The Common and Mzab Gundi are hunted and eaten by local tribes, however most gundis do not live around villages. These species plus the Speke’s Gundi are listed as Least Concern under the IUCN Red List. The Felou Gundi was originally listed as Vulnerable, but in 2004 was relisted as Data Deficient. It is believed that they were affected by droughts, which will only worsen with climate change. However, the populations are expected to stay at a healthy threshold, even with decreasing habitat conditions.  

Author: Sidney Sanchez

This family includes eight species of chinchilla rats and two species of Inca rats. While once thought to be in the same superfamily as chinchillas, DNA evidence shows that chinchilla rats are actually more related to degus than chinchillas. Both chinchilla rats and Inca rats have nearly parallel maxillary tooth rows and are hypeselodont. The ceca of both species are long and wide due to their herbivorous diets. Charles Darwin collected the first described specimen of this family, which was the Bennett’s chinchilla rat.

Chinchilla rats have thick and long silky fur, with bristles on their claws used for grooming. Their ears are large and almost naked, and their whiskers are long and reach the shoulder when pressed back. Due to their small claws and narrow incisor teeth, these animals are not adapted for digging. They are distinguished by a line of white hairs on their chest that acts as a sternal gland and stands out from the rest of their dark fur. Inca rats have a larger head and a longer body length than chinchilla rats, and have stronger curved claws. They also have some white markings on their face and tail.

Every species of chinchilla rat lives in elevations above 1800 m on the eastern slopes of the Andes, except for Bennett’s chinchilla rat, which lives from sea level to 4000 m elevation on the western slopes of the Andes. The rest of the species live at elevations ranging from 2000-5000 m from southern Peru to Chile. They live in shrublands, montane grasslands, moist forest, and arid deserts. Inca rats only live in the upper montane and in wet forests at elevations of 2650-3000 m, where bamboo and sessile ferns grow. The species of Abrocomidae are browsers and grazers, with some exhibition of granivory and frugivory. Some chinchilla rats can eat plants high in resins and toxins. 

Chinchilla rats climb rocks and small trees and rest under rocks or in burrows. They live in rock fissures which contain tunnels. Bennett’s chinchilla rats share these burrows with degus, but these burrows may be dug by other species, since their claws are so small. To avoid being attacked, this species of chinchilla rat has an alarm call, and Ashy chinchilla rats emit grunts. Chinchilla rats live in small colonies, and populations are usually low, due to few individuals being captured during multi-year studies. Chinchilla rats take dust baths, which may aid in olfactory communication and in the grooming of their fur. The litters of chinchilla rats range from 1-6 young, while Ashy chinchilla rats’ average 2.2 young per litter. They have a long gestation period of 115-118 days, compared to the degu, which has a gestation period of 90 days. This suggests that there may be a relationship between the slow gestation period and the low-productivity and high-elevation climates of where they live. 

Human activities have largely contributed to the decline of chinchilla rats’ habitats, through livestock grazing and deforestation. Some parts of the Andes where chinchilla rats are endemic only have 1-10% of original habitat remaining. Chinchilla rat skins were found sold in local markets as a counterfeit of the Short-tailed chinchilla. The Incas of Machu Picchu are believed to have used chinchilla rats as food and as pets, since they have been found to be buried alongside humans. There are currently ten protected areas in the distribution of Bennett’s chinchilla rat, and there are 20 protected areas in the range of the Ashy chinchilla rat in Peru, Argentina, Bolivia and Chile. Both of these species are listed as Least Concern on the IUCN Red List. The rest of the species in Abrocomidae have population extents that are unknown but unlikely to be extinct. The Machu Picchu Inca rat used to be listed as Extinct, but a living specimen was recently found near Machu Picchu.

Author: Sidney Sanchez

The family Bathyergidae contains African mole rats and is within the suborder Hystricomorpha of the order Rodentia. Evidence shows that members of this family belong to the Old World Hystricognathi lineage and are closely related to Petromuridae, Thyronomyidae, and Hystricidae. The divergence of the Old World and New World lineages occurred during the Eocene in Africa. Bathyergids originate in sub-Saharan Africa and are small to medium sized. Bathyergidae consists of 5 genera and 16 species. The genera are Georychus, Heterocephalus, Heliophobius, and Bathyergus. These five genera are further separated into two subfamilies. The first subfamily, Bathyerginae, includes the genus Bathyergus and its two species. This subfamily is characterized by large front claws and a groove in their upper incisors. The second subfamily, Heterocephalinae, includes the genera Georychus, Heliophobius, Cryptomys, and Heterocephalus. This subfamily lacks the large claws and groove in their upper incisors. Species within this family include the naked mole-rat and the silvery mole-rat.

All members of the family live fossorial lifestyles and have physical characteristics to accommodate such a living. These characteristics include short legs, a tapered body, small ears and eyes, and large incisors. In order to burrow, bathyergids utilize their powerful incisors to loosen dirt and then move said dirt away from their path with their short arms. This is true for all members of the family apart from the genus Bathyergus, which uses its arms to burrow. Due to the presence of small eyes, bathyergids do not use sight frequently, if at all, when underground. The sense of touch, however, is vital to the family. When underground, bathyergids feel for their surroundings by using their short tails and long hairs made specifically for such purpose. Members also have hypsodont dentition, which reflects their herbivorous diet. Compared to other rodents, bathyergids have a much longer lifespan, which is often between 12 and 26 years. The genera Heterocephalus and Cryptomys are unique based on their social systems, which can include one mating female along with several males and non-mating female helpers.

Work Cited
Kingdon et al. (2013). Mammals of Africa, Volumes 1-6. Retrieved from https://www.books.google.com/
Myers, P. 2000. “Bathyergidae blesmoles and mole rats.” (Online). Animal Diversity Web. Accessed April 15, 2015 at https://animaldiversity.org/accounts/Bathyergidae/

Author: Anna Cole

The family Caviidae contains six genera and 20 species, plus one domesticated species. There are three subfamilies: Caviinae (Guinea pigs, Cavia; yellow-toothed cavies, Galea; mountain cavies, Microcavia), Hydrochoerinae (capybaras, Hydrochoerus; rock cavies, Kerodon), and Dolichotinae (maras, Dolichotis). Caviids are medium to large-sized rodents with compact bodies, short limbs, and big heads, with the Greater capybara being the largest rodent in the world. The earliest caviid fossil comes from the Miocene in South America, and the emergence of the clade Cavioidea appeared 26-28 million years ago.

All species in the subfamilies of Caviinae and Hydrochoerine are tailless and have large heads, with three toes on the hind feet and four toes on the forefeet. In Caviinae, the digits are clawed, but the digits in Hydrochoerine are smoothed nails. There is great variability in the subfamily Dolichotinae. The heads of these species are large when compared to their bodies, and they have three large hoof-like toes on the hind feet and four toes with sharp claws on the forefeet. All caviids have the same dental formula, with teeth that never stop growing, and all possess enlarged infraorbital foramen. Galea species have distinctive yellow incisors and less complex cusp patterns than Cavia. The teeth of Microcavia are similar to Galea, and have the largest bullae compared to the cranium out of the three genera. Dolichotis skulls are more compressed with broad frontal bones and specialized nasals that do not reach the premaxillae.

Caviids mostly live in arid and semiarid open habitats, but when in forested areas, live near rivers and open patches. The Patagonian mara lives in grasslands and steppe formations in Southern Argentina, while the Chacoan mara inhabits thorn-scrub areas of the Argentine, Bolivian and Paraguayan Chaco. Microcavia mountain cavies also live in arid and semiarid open formations and favor high-elevated regions of Bolivia, Chile, and Argentina. Cavia species have a broad distribution, with the Brazilian guinea pig living in high-elevation grasslands of western South America to the Llanos grasslands in Venezuela. Other guinea pigs live in grassy, open regions in eastern Brazil. In the Hydrochoerines, the Rock cavy occurs in rock outcrops in semiarid caatinga, and the Acrobatic cavy is restricted to the dry cerrado forest limestone outcrops. Both the Greater capybara and the Lesser capybara inhabit semi-aquatic regions near bodies of water. The locomotion of Caviidae is highly terrestrial in guinea pigs and yellow-toothed cavies, cursorial in maras, scansorial in mountain cavies, semiarboreal in cavies, and semi-aquatic in capybaras. All caviids are active throughout the year, but peak during twilight. Predators include the Tayra, the Lesser grison, the Greater grison, small cats, and foxes. Pumas and jaguars also prey on capybaras.

Caviids are social creatures that have many forms of communication relating to their social organization, including vocal sounds and specialized scent glands used by dragging the anus on the ground. When threatened, the Southern mountain cavy makes a short “tsit” sound before running away, and the capybara barks when scared. The Rock cavy begins its alarm call as a low sound that increases into a piercing whistle. Some other noises include the capybara’s purr, the cavy’s and mara’s whistle, the yellow-toothed cavy’s chirp, and the mountain cavy’s shriek. 

All species of Caviidae are herbivores and eat grasses, with some browsing. Guinea pigs and yellow-toothed cavies also consume small forbs, while mountain cavies rely on desert shrubs since they live in arid climates. Both species of mara also consume the fruits of shrubs, and capybaras eat the green vegetation along wetlands and riverbanks. Rock cavies have the most varied diet because they forage on leaves, flowers, fruits, bark, and branches of shrubs and trees. Since grasses contain indigestible cellulose, all caviids exhibit coprophagy, which is the re-ingestion of fecal matter to absorb all of the nutrients. 

Caviids give birth to precocial young, who are born with open eyes and the ability to walk right after birth. Litter sizes are usually smaller in species living in arid regions, while larger species have longer gestation periods. Smaller species like mountain cavies reach sexual maturity at 40-50 days, and larger species like capybaras reach sexual maturity at around 18 months. Data on the life spans of caviids is sparse, but the species living in captivity live longer than the wild species. Tropical species, like capybaras, breed throughout the year, but species living in arid zones show some seasonal variation in reproduction. Their mating system is classified as promiscuous, but the Brazilian guinea pig has been described as harem-based with little promiscuity. The males are heavier than the females, and young males wait for the chance to replace the dominant male. The Highland and Lowland yellow-toothed cavies are solitary and most likely promiscuous, with the home ranges of males being five times larger than the females’ home ranges. The males and females of Spix’s yellow-toothed cavy are both aggressive and do not exhibit social grooming or contact. Mountain cavies have been described as promiscuous and polygynous. The males and females of the Patagonian mara form pair bonds and defend their burrows. Species of Hydrochoerinae exhibit a form of polygyny based on defending limited resources by a dominant male, which allows males to gain mates that aggregate around the resource. In Kerodon species, this limited resource is boulder piles found in northeastern Brazil. Male rock cavies defend clusters of rock and alert the harem of females when there is a threat. Capybaras defend temporary pools and bodies of water, with males maintaining a strong dominance hierarchy. 

In general, caviids are not significant crop pests. They are hunted for food and for leather, even though hunting is illegal in most of Brazil, except for subsistence by the indigenous population. Kerodon are highly prized as a protein source in northeastern Brazil, and capybaras are hunted for their leather, which is used in the manufacturing of gloves, slippers, and jackets in Argentina. The domestic guinea pig was derived from the Montane guinea pig from the Andean highlands and is considered an important source of protein in Peru and Bolivia, as 65 million domestic guinea pigs are eaten annually in Peru alone. Most caviids are tolerant to some habitat disturbance since they can live in a mosaic of landscapes. Shipton’s mountain cavy is classified as Near Threatened on the IUCN Red List and the Santa Catarina’s guinea pig is Critically Endangered and is one of the rarest mammals in the world since it only lives in an area of less than 10-hectares on Moleques do Sul Island off the Brazilian coast, with a population of only 42 individuals. The Patagonian mara is Near Threatened because of habitat degradation and competition with livestock, but the rest of the caviid species are Least Concern or Data Deficient.

Author: Sidney Sanchez

Chinchillidae is a family of medium to large-sized chinchillas and viscachas in the order Rodentia, the suborder Hystricomorpha, and the Infraorder Hystricognathi. Little research has been conducted regarding the family’s phylogenetic history. However, recent studies have shown that the family is a monophyletic clade that is related to Dinomyidae, another small mammalian family from South America. The family Chinchillidae includes three extinct genera and three extant genera: Chinchilla, consisting of the species Chinchilla chinchilla and Chinchilla lanigera, Lagidium with the species Laguidium peruanum, Lagidium viscacia, Lagidium wolffsohni, and Lagidium ahuacaense, and Lagostomus with the species Lagostomus maximus. The family Chinchillidae first appeared in South America during the Oligocene. Members of the family commonly live in areas with rocky terrain, open areas, and shrub lands. Animals habituating in higher elevations protect themselves by burrowing, but are not known for their speed or adept digging capabilities. Animals habituating in the plains, however, live in subterranean colonies and are able to navigate efficiently enough to evade predators.

Members of Chinchillidae originated in Southern South America, specifically in the Andes mountains. Adaptations to fit this rough and rocky terrain include fleshy foot pads, called pallipes, strong hind legs, and long bushy tails. Chinchillids are herbivorous and have cheek teeth that continue to grow throughout the individual’s life. The chinchillid jaw is also hystricognathous based on the absence of an infraorbital plate and the partial passage of muscles through the infraorbital foramen. Additional adaptations include short front legs and long back legs. This reflects the occassional locomotion of bipedal jumping exhibited by chinchillids. The number of digits varies between chinchillas and viscachas, with the former have four and the latter having three. Chinchillas are a popular commodity in the pet trade and clothing industry due to their cute appearance and soft fur. Because of this, the wild population is decreasing dramatically, and is considered to be critically endangered.

Work Cited
Myers, P. 2000. “Chinchillidae chinchillas and viscachas” (Online). Animal Diversity Web. Accessed February 24, 2015 at https://animaldiversity.org/accounts/Chinchillidae/
Spotorno, A. et al. (2004). “Molecular divergence and phylogenetic relationships of chinchillids.” Journal of Mammalogy 85.3 (2004). Web. 24 February 2015.
Vaughn, T. et al. (2013). Mammalogy. Pg. 227-228. Retrieved from: https://www.books.google.com

Author: Anna Cole

The family Ctenomyidae, known as tuco-tucos, includes one genus, Ctenomys with 65 species; all are found in central and southern South America up to 4,000 m in elevation. The fossil record show that the family extends to the early Pliocene and that they are closely related to the family Octodontidae. Ctenomys are fossorial species with small ears and eyes and powerful bodies. They inhabit mostly areas with sandy and loamy soil with a few species living in dry grasslands. They dig using their forefeet which are equipped with extremely long and strong claws to loosen the packed earth to build complex, branched burrow systems. Ctenomys urinate on the compacted soil in order to soften the ground for them to dig with their claws, as well as their incisors. These burrow systems are built with different chambers that are used for nesting and storing food, such as roots, stems and grasses that they store to feed on.

In a few of the Ctenomys species there is a complex social system and the burrows are used by many individuals, but in most other species the burrows in the colonies are used by single individuals or mothers with young. The species use vocalization to communicate various signals, such as establishing territories, in mating rituals or as a fear response. When some species are threaten and confronted by an intruder they will attack; other species when threatened will back into their burrows and use their tail as a sensing organ. The complex burrows systems that Ctenomys build are used by other mammals, lizards, toads, invertebrates and sometimes birds as shelter. Although tucos-tucos can damage crops and the root systems of the fruit trees, and the burrows create problems for livestock, they also aerate and fertilize the soil helping with the maintenance of soil fertility for other plants benefiting herbivores, as well growth of crops.

Work Cited
Myers, P. 2000. “Ctenomyidae” (Online), Animal Diversity Web. Accessed January 23, 2015 at https://animaldiversity.org/accounts/Ctenomyidae/

Author: Rebeca Mendez

The two species are Cuniculus paca, the lowland paca and Cuniculus taczanowskii, the mountain paca. The pacas’ fossil records began in the Oligocene. They are found in Central and South America ranging from east central Mexico to Paraguay. Overall, their biogeographic region consists of the southern portion of the new world, the neotropics. Their preferred habitat is near rivers and streams in tropical forests. Near these water sources, the pacas are found at sea level to about 300 m elevation. This family consists of plant-eating rodents who compete with other species for food sources due to overlapping diets and habitats. Also, the pacas’ economic importance for humans is both positive and negative because they are considered a tender and mild-flavored food source as well as a crop pest in some areas.

Cuniculids are known to be terrestrial, nocturnal, and solitary mammals that prefer to be alongside bodies of water for the construction of burrows in banks, slopes, or between rocks and tree roots. The water sources provide an efficient escape from predators; however, they usually do not dive or forage in the water. Although they are solitary rodents, pacas communicate by use of vocalizations, foot thumping, and tooth grinding. An interesting characteristic of cuniculids is their morphology. They have chunky bodies with short, stout legs; however, their hind limbs are longer than their forelimbs. They have large heads with large eyes. They are nearly tailless. The cuniculids have coarse pelage without under fur. Their skulls are also unmistakable because they are broad and massive with short nasals and long frontals. The pacas’ zygomatic arches are inflated to form a hollow, resonating chamber that is used to amplify sound.

Work Cited
Myers, P. 2000. “Cuniculidae” (On-line), Animal Diversity Web. Accessed November 22, 2014 at https://animaldiversity.ummz.umich.edu/accounts/Cuniculidae/#behavior

Author: Stacie Garcia

Dasyproctidae is split into 2 genera, the agoutis and acouchys, and 15 species. Their earliest fossil records date back to the early Oligocene, however they do not fit within the Dasyproctid genera currently recognized. This taxonomic incertitude has bled into the organization of the genus Dasyprocta, as species/subspecies numbers and ranges are poorly understood. 

Although their history and taxonomic standing are murky, all species within Dasyproctidae have large heads, bulging jaw muscles, large eyes, short ears, a slender body, large hindquarters, a hunched back, and thin, elongated limbs. They inhabit tropical forests, brush lands, dry forests, and savannas of the Neotropical Region. Some species of Dasyprocta are particularly effective in adapting to human disturbance, making them somewhat common in agricultural areas and gardens. Dasyproctids are largely herbivorous and undergo a “scatter-hoarding” behavior of caching intact seeds for storage. This behavior greatly aids in seed dispersal and, therefore, a healthy forest composition that would be otherwise less diverse in their absence. That said, the Red acouchy has been known to manipulate a rapidly germinating seed hoard by removing radicles and epicotyls to stunt seed growth. 

Agoutis and acouchys are important food sources for humans throughout their range. Although some can be seen as agricultural pests, their effect on crops is not relatively significant, and excessive hunting in this regard is a worry for endemic species. Another growing threat is Amazonian forest fragmentation, and although a majority of dasyproctids are listed as Least Concern on the IUCN Red List, further monitoring is recommended. 

Author: Carson Hood

This family is represented by a single living specimen, the Kha-nyou or Laotian Rock Rat (Laonastes aenigmamus) and was first described in 2005. Originally, this species was in its own family, Laonasatidae due to the combination of having characteristics of both hystricognathous and sciurognathous suborders. However, it was found that four fossil genera are also part of the family Diatomyidae but which went extinct over 11 million years ago. These fossils were found around Pakistan, India, Thailand and China. 

The Kha-nyou has an elongated head and a rat-like body with a long, densely furred tail. They live in limestone karst in forests and are only found in two provinces in Laos and were recently found in a national park in Vietnam. According to the accounts of local people, these animals are nocturnal or crepuscular and live in rock crevices during the day and forage on the forest floor at night. Based on tooth morphology, it is assumed that they are herbivorous and partially folivorous. The local people claim that these rodents also eat leaves, fruits, seeds, roots and some insects. Captured Kha-nyou have been observed eating the sap of euphorbias, which contains toxic terpenes, implying they have a specialized digestive system. It is believed that females give birth to one or two young, as noted by the local villagers. 

Captive Kha-nyou easily climb into narrow crevices in the karst, but do not jump, run, or climb steep slopes. Instead, they are slow on the ground and move awkwardly on flat surfaces. It is assumed that these animals are unable to disperse far from the limestone karst, leading to fragmented populations. Locals have stated that they stay in groups of around ten individuals, composed mostly of females. The Kha-nyou are hunted by local villagers for food, which may lead to overhunting, since this species is already threatened by forest clearing and quarrying for limestone. They are listed as Endangered and are protected under Laos authorities. The Vietnamese population has not been assessed yet, as it has been recently discovered.  

Author: Sidney Sanchez

This family includes one extant species: the Pacarana, which is a black and white spotted, heavy-bodied rodent that inhabits the tropical forests of the Neotropical region. Dinomyids appeared in the fossil record 29-21 million years ago in present-day Bolivia, but at least 50 species and 22 genera that once belonged to this family are now extinct. The two largest known rodents belonged to Dinomyidae, with Phoberomys weighing 700 kg and Josephoartigasia weighing 1000 kg. The placement of this family has been debated, but recent molecular data shows a relationship with Chinchillidae. However, morphological and parasite data supports a relationship with Erethizontidae, but this could just be an example of convergent evolution. 

The Pacarana’s black body and white patches are thought to be defense against predators by camouflaging it with the dark rainforest. The males are black, while the females are brown, but both sexes have short and rounded ears placed on a large head. Characterized by claws and webbing between the toes, the Pacarana has plantigrade locomotion. It will raise its hind feet when walking, resulting in a waddling gait. When running, the hindfeet do not touch the ground, which shows a semi-digitigrade walk. Although the Pacarana has claws, it is not known to dig. The tail allows it to use bipedal locomotion, as seen in social encounters. 

Pacaranas live in thick, humid, and undisturbed forests of the Andes, which includes Columbia, Venezuela, Ecuador, Peru, Brazil and Bolivia, at elevations of 240 m to 3400 m. They prefer rocky slopes near rivers and streams. The dens are found at the base of slopes and are created with large piles of rocks. The burrows, latrines, and foraging areas are connected via tunnels in the understory vegetation. Groups will leave the dens at dusk, with the largest individual leading first, and return individually to the den at midnight, tail first. 

In captivity, Pacaranas prefer to eat corn, beans, squash, and bananas. In the wild, Pacaranas eat a wide variety of plants that are high in fiber, low in fat, and have an important concentration of ash. They also eat fruits, herbs, shrubs, leaves, stems, and nuts. Pacaranas play a significant role in seed dispersal since they eat the pulp of fruits but do not digest the seeds, which are dispersed through feces. Up to 31% of their time is spent eating, since they gnaw and chew slowly. 

This species of rodent is nocturnal, crepuscular, and terrestrial. They spend the day in their dens and venture out at dusk. They are either solitary or occur as a male-female pair and have an average of 2-4 young. Males produce a white secretion from glands around their eyes that drain into their nasal cavities, which are then deposited onto branches through the rubbing of their cheeks. This form of marking also happens during grooming and may keep their pelage maintained. In captivity, sexual maturity is reached in 24 months for males and in 18 months for females, but Pacaranas do not have a designated breeding period. Male courtship rituals include grooming, trembling the forefeet, and frisky hops. Females give birth to precocial young in burrows. The babies will be able to groom only days after birth, eat solid foods at two weeks, and will stay in close contact with the mother for an extended period. 

The Pacarana is not abundant anywhere in its range, and locals rarely report seeing the animals. However, they are still hunted as bushmeat and as a trophy animal, with domestic dogs trained to locate them. Their large size and slow movements make them an easy target for hunters. Pacaranas face a high risk of extinction due to deforestation and livestock grazing. Some farmers consider them to be crop pests, and will kill them when spotted. The Pacarana plays an important part in forest succession, so there have been efforts to preserve the forest patches and burrows they inhabit.

Author: Sidney Sanchez

Echimyidae is a large family split into 3 subfamilies, 4 tribes, 27 genera, 99 species, and roughly 130 taxa. These hutias, South-American spiny-rats, and coypu inhabit lowland and highland forested habitats, lowland open dry habitats, and wetlands of the Neotropical Region. Echimyids resemble rats, yet they can range from small to large in size and vary significantly in pelage texture and coloration. The family originated in the late Oligocene/early Miocene, and has recently seen a reshuffling in classification relating to overall expansion and the redefinition of generic limits of traditionally placed taxa. The subfamily Capromyinae was previously considered a separate family, Capromyidae, but has since been absorbed into Echimyidae. 

Echimyids have developed significant ecomorphological adaptations as a result of their remarkably diverse niche colonization. Many Echimyid species’ movement from a terrestrial origin to arboreal, semi-fossorial, and amphibious niches has made them an interesting group to study structural, functional, and behavioral convergences in relation to locomotion. Communication for this family is scent-based, and their diet is largely made up of fruit. Although around half of this family is considered Least Concern on the IUCN Red List, 21 species are considered at-risk due to human-induced habitat loss. Other threats include hunting, pathogens, and invasive species competition. The remaining species of echimyids are Data Deficient, and would benefit from more detailed research. 

Author: Carson Hood

Erethizontidae includes 3 genera, 17 species, and 23 taxa of New World porcupines. These porcupines are arboreal, herbivorous, and found in Nearctic and Neotropical regions of North, Central, and South America. Although their small to medium-sized bodies are covered with the telltale ‘quills’ or ‘spines’ well known for the animal, this family is not closely related to the Old World species of the same common name. The divergence between Old and New World species of porcupines began around 36 million years ago during the late Eocene, but the status of familial and intrafamilial taxonomic organization is not well established. Within Erethizontidae are 2 subfamilies: Chaetomyinae and Erethizontinae. Chaetomyinae is monotypic, comprising the Broomstraw-spined Porcupine. Erethizontinae is made up of the remaining 16 species, 2 of which have been discovered since 2013. 

Erethizontids have 3 types of specially modified hairs, or quills, exclusive to this family. Defensive quills can easily detach upon contact with a predator, and are distinct from Old World species in that the tips of these quills have microscopic barbs that anchor them into the skin of the aggressor. Bristle-quills are the second modified hair type of Erethizontids, marked by their flexibility and length, and their purpose is unknown. The last type is only found in the Broomstraw-spined Porcupine, and are dry and wavy like bristles on a broom. These quills are not only a visual deterrent to predators, but in the case of the North American Porcupine, they serve as odor diffusers. During a warning display, glands are expressed with the raising of their quills, releasing an odorant that halts predators. Although these factors have made the porcupine of interest to humans, they have also been hunted for meat and to control damage to trees in their habitat. More information on the taxonomic status of many Erethizontid species is necessary to establish their conservation status, as most are Data Deficient. 

Author: Carson Hood

This family only contains the Naked mole-rat, a small and cylindrical rodent best known for its loose and wrinkly skin, long front incisors, and tiny eyes and ears. Although this animal is not covered in hair, the Naked mole-rat instead has coarse, sensory vibrissae, which helps in navigating the underground tunnel systems they live in. Naked mole-rats live solely underground, favoring soils that are hard and consolidated. They live in arid bushland, thicket, and semi-desert habitats that have high temperatures and low rainfall.   

The Naked mole-rat used to be placed in the African mole-rat family Bathyergidae but is now in its own family. Both Heterocephalidae and Bathyergidae species have laryngeal and pharyngeal skeletal systems modified for digging underground, indicating that they are distant relatives, and diverged around 32 million years ago. The biggest difference between the Naked mole-rat and African mole-rat is that the Naked mole-rat has no hair, while the African mole-rat is covered in fur. 

The underground environment is rich in carbon and low in oxygen, making the metabolic rates of Naked mole-rats low. An average of 40-80 individuals live in these below ground colonies. As social animals, they will huddle together for warmth, since temperatures can be around 12-37 degrees Celsius. Occasionally, they will also bask in shallow tunnels during the day. To escape the heat, they will dig into deeper burrows. These tunnel systems are carved by their incisors and will burrow after rain, so the soil is softer. Naked mole-rats work together to dig these tunnels, with a line of mole-rats gnawing at the soil and kicking it behind them, until reaching a worker that is stationed near the opening of the tunnel. Naked mole-rats use a wide variety of high-pitched vocalizations to communicate size, dominance, and even individual identity. 

The diet of Naked mole-rats include bulbs, roots, and tubers, which are deposited in nest chambers in the colony. They do not drink water; instead, they obtain their water from ingesting succulent plants. Like other rodents, they rely on coprophagy, which means they eat their fecal pellets to extract all dietary nutrients. Predators include snakes, raptors, and owls.

Naked mole-rats become sexually mature at 7-9 months, but only a few individuals breed. There is a single breeding female, and she is the most aggressive individual in the colony. She chooses which males to breed with, who are often the older and heavier males. When pregnant, she is taken care of by subordinates, who also care for her offspring. Wild Naked mole-rats may produce more than 50 young in 4-5 litters annually. Non-breeding Naked mole-rats defend the colony, dig tunnels, harvest food, and take care of young. 

Some remarkable features of Naked mole-rats include their long lifespan of up to 30 years, their tolerance to hypoxia, and resistance to cancer. They are classified as Least Concern on the IUCN Red List, since they live in areas too dry for agriculture, and because they live underground and away from human activities. 

Author: Sidney Sanchez

Hystricidae is the family of Old World porcupines, which are medium to large sized rodents, recognized by the long and sharp spines that cover their bodies and used for defense. This family contains three genera and eleven species, from the Afrotropical, Palearctic and Indo-Malayan regions. Hystricid porcupines can live in coastal shrubland, savanna grasslands, semi-deserts, tropical forests, and even urbanized areas. They are more closely related to cane rats, classic rats, and African mole rats than they are related to New World porcupines. The New World porcupines are more related to chinchillas and spiny rats. 

Hystricid porcupines are nocturnal and are able to travel for long periods of time in search of food at nighttime. During the day, they rest in burrows or in cavities under forest trees. Inside of these dens, a nest is constructed with plant materials. Old World porcupines are herbivores and consume a wide variety of fruits, berries, bark, and roots. They can be considered ecosystem engineers, as the Crested porcupine digs conical holes into the surface when looking for food, which allows water to infiltrate the crust. Bark feeding also controls plant succession. 

The size and length of the spines on Old World porcupines differ by species, but all have a black or brown body with white bands on the quills. The spines are circular in cross section with a spongy interior, surrounded by stiff keratin. Both ends of the spikes are pointed and can easily penetrate the skin of predators. Old World porcupines also have tactile bristles, which are flexible, modified hairs used in sensory functions. The contrasting whites and blacks on the quills serve as aposematic or “warning” coloration. When threatened, the Old World porcupines rattle their spines, stomp their feet, grunt, and may even attack by pushing their quills into the predator’s skin. New World porcupines do not attack predators, and they also have shorter quills. 

The Cape, Crested, and Indian porcupines are social and live in family groups, while the African Brush-tailed porcupine feeds alone at night. However, they have been known to share dens and exhibit mutual grooming in captivity. Both males and females use scent marking to claim their territory via secretions from their perianal glands. The gestation period lasts between 90-120 days, and reproductive maturity occurs around one year of age. Litter sizes are typically between one to three precocial young, which means they are born fully furred and with open eyes. The quills do not harden until one week of age, and the average lifespan in captivity is over 20 years. Three species of Old World porcupines are monogamous, which is usually rare in mammals. The male provides the same amount of parental care as the female (besides the suckling and licking of the anogential areas on the young). The males and females of Cape and Indian crested porcupines participate in sexual activities regularly throughout the year, even outside of the breeding season, which strengthens the pair bond.

Old World porcupines are hunted and eaten as food by humans, and the quills are used for apparel. The African brush-tailed porcupine is hunted as bushmeat in Nigeria, causing its population numbers to decline. The Indian crested porcupine is hunted for food and poached due to its role as an agricultural pest. However, populations of the Cape porcupine have increased in South Africa due to the rise of agricultural activity. The porcupine is listed as Vulnerable, and its population is projected to decline by 30% due to forest loss, hunting as bushmeat, and from the pet trade. Since Old World porcupines act as ecosystem engineers, it is important to conserve these species to better protect entire animal communities. 

Author: Sidney Sanchez

The family Octodontidae is made up of 8 genera, 14 species, and 16 taxa of herbivorous viscacha rats, degus, rock rats, and the coruro. They have a particularly restricted range with a rather diverse habitat preference of coastal areas in central Chile, pre-Andean and Andean regions, desert and semi-desert scrublands, rainforests, and Mediterranean habitats of the southern Neotropical Region. These small to medium-sized rodents are marked by dense and soft pelage, large heads, pointed noses with long vibrissae, and short feet. The family’s name refers to the figure-eight shape of the molars. 

Octodontidae is split into 2 macro-niches based on geographic division; the Argentinian clade and the Chilean clade. The Chilean clade is made up of more social species, and with this comes interestingly complex vocal repertoires. The Argentinian clade is more solitary, suited for arid regions. Because of this difference, burrow systems vary wildly between clades. Some burrow systems house one individual, while others have communal nest sites. 

While most species are neutral in terms of human impact, degus within this family can be both significant agricultural pests and crucially important laboratory research subjects for issues regarding Alzheimer’s, diabetes, and even cataracts. Deforestation, livestock production, and mining are the most serious threats facing octodontids, and many species currently are Data Deficient. On the IUCN Red List, 3 species are currently Critically Endangered and 1 is Vulnerable. Further research on habitat preference and population status and trends is recommended. 

Author: Carson Hood

Petromuridae consists of 1 genus, 1 species, and 1 extant taxon: Petromus typicus. This species should be known as the Noki, yet it is more commonly known as the Dassie rat even though it is neither of those animals. The Noki is found in arid, rocky habitats of south-western Angola, western Namibia, and north-western South Africa. Although their range is currently limited, their fossil record suggests a history of a more widespread African distribution. 

The body of the Noki is aptly equipped for their preferred desert habitats with flexible ribs, a flattened skull, large eyes, and a pointed muzzle for squeezing into crevices. They look like a cross between a rat and squirrel in their pelage coloration, round ears, and tail length. They are herbivorous, and tend to live in small family groups that aid in predator evasion during foraging. In fact, while the Noki has its own alarm call to warn for predators, it has also been seen to respond to the predator call of rock hyraxes. The Noki has no common human interaction and is classified as Least Concern on the IUCN Red List. 

Author: Carson Hood

The family Thryonomyidae, also called cane rats, has one genus, Thryonomys, which includes two species: T. gregorianus (the Lesser cane rat) and T. swimderianus (the Greater cane rat). The family dates to the Eocene with fossils distributed in Asia, Europe and Africa. The family can now be found south of the Sahara in Africa. Thryonomyids are mostly found in wet or swampy areas that have abundant grass, and they sometimes extend into agricultural areas. T. gregorianus uses tall grass for shelter and they sometimes dig shallow burrows or use rock crevices, termite mounds and abandoned aardvark or porcupine holes as shelter. On other occasions this species was observed inhabiting edges along swamps. T. swimderiamus are the more fully aquatic of the two species and they occur near marshes and river banks occasionally expanding into habitats near farmlands.

Thryonomys are large (4 to 6 kg) and have stocky bodies and limbs that are short and powerful with thick, strong claws that are adapted for digging. Thryonomys males initiate courtship by wagging their tails and treading their hind legs. Males duel by pushing each other nose to nose to establish dominance within their social group hierarchy. These nocturnal herbivores make well defined paths that go from feeding areas to water by pounding down dense grass. This family is sometimes found in small groups, but are usually solitary. Thryonomys hold an important significance as wild animals for humans in that in some areas they are hunted for their high protein meat. Due to their value as a source of protein humans have started to domesticate them, which helps to relieve the pressure placed on the wild populations.

Work Cited
Myers, P. 2000. “Thryonomyidae” (Online), Animal Diversity Web. Accessed January 23, 2015 at https://animaldiversity.org/accounts/Thryonomyidae/
Antonanza, R.L., Sen, S. and Mein, P. 2004. Systematics and phylogeny of the cane rats (Rodentia: Thryonomyidae). Zoological Journal of the Linnean Society. 142: 423–444

Author: Rebeca Mendez

Dipodidae is made up of 13 genera of 35 species known as Jerboas located within the superfamily Dipodoidea under the suborder Myomorpha. Their period of origin has been reason for debate, as has their general taxonomy and phylogeny, but the leading theory suggests this family began in the late Paleocene as a divergence from Muroidea. Dipodidae is commonly organized into 4 subfamilies: Cardiocraniinae (pygmy jerboas), Euchoreutinae (long-eared jerboas), Allactaginae (five-toed jerboas), and Dipodinae (three-toed jerboas); however, the systematics of Dipodidae as a whole has proven controversial.

Jerboas are characterized by their short forelimbs and strong hindlimbs. They are small to medium-sized and bipedal, adapted to running in desert habitats of Palearctic and Afrotropical regions. They are also known for their distinctive tails, often ending with tufts of long black and white hairs, that aid in balance. Some pygmy jerboas instead have dense, untufted tails for fat storage. Jerboas are nocturnal, sleeping in shaded burrow networks underground. When active, they move in zig-zag patterns and can run long distances to evade predators. They are omnivorous and typically solitary. Although only 4 of 35 species are currently listed under special status on the IUCN Red List, habitat encroachment due to agriculture has caused population declines in multiple species.

Author: Carson Hood

Sminthidae is comprised entirely of birch mice and classified in the suborder Myomorpha, within the superfamily Dipodoidea. This family is made up of 1 extant genus, Sicista, containing 14 species and is notably one of the oldest rodent genera. Sminthidae’s origin is said to be during the geologic instability of the middle Eocene, where environmental change to more open habitats promoted varying methods of rapid locomotion in small mammals, leading to Sminthidae’s unique quality of having no distinct hindlimb specialization. They do, however, have a pseudo-opposable toe that aids in their apt climbing ability.  

Birch mice are a small omnivorous rodent species, often having signature dark brown stripes stretching from their head to the base of their long prehensile tail. They occur solely in the Palearctic region, and reside in grasslands, shrublands, steppes, semi-deserts, and forests. These mice are crepuscular, nocturnal, and undergo hibernation in the winter. Their nest sites are often comprised of an above-ground structure, such as tree stumps or decaying logs, with attached underground burrows. Habitat loss is a driving factor in population declines, especially in European species.

Author: Carson Hood

The family Zapodidae is met with some controversy, as there are varied opinions about the status as a distinct family or as a subfamily of the Old World Family Dipodidae. They were described as being separated from the Old World by Coues in 1875. We treat it as a distinct family for this website. The group currently recognizes three genera and five species. This family is collectively known as jumping mice, and they are mostly restricted to the middle and northern parts of North America. Their habitat generally consists of moist meadows and the edge of woodlands, although some species prefer deep forests near streams.

Only one non-American species, Eozapus setchuanus, is known. It is native to China, and is the only representative of the genus Eozapus. The other two genera, Zapus and Napaeozapus, are native to North America. The main difference between the two American genera is the absence of a minute upper premolar in Napaeozapus. As a family, the members closely resemble each other, especially in size and color. They are slightly larger than the common house mouse, and have long limbs. Their coloration is yellowish brown on top, with a white underside and a broad line of yellowish orange separating the two sides. Napaeozapus also has a characteristic white tip on the tail.

Members of Zapodidae serve an important ecological role through seed dispersal. Napaeozapus insignis, or the western jumping mouse, is thought to benefit trees of economic importance through their dispersal of mycorrhizal fungi. They also are of some importance as a prey species for a variety of animals, including gray wolves and bobcats. Many species of Zapodidae are primarily nocturnal, although they are known to forage during daytime hours as well. Members of this group burrow and build underground nests, where they then spend winters in hibernation. They are active for only a short time each year. The normal mode of locomotion is a quadrupedal walk, although a quadrupedal hop is also used. This hop can be as long as 1.8 m, although the average is around 0.9 m, and can be as high as 0.6 m. Jumping mice are omnivorous generalists, with primary food sources including fruits, seeds, fungi and insects. All members of Zapodidae are listed as being of Least Concern on the IUCN RedList.

Work Cited
Allen, J.A. “The North-American Jumping Mice.” The American Naturalist 34.399 (1900): 199-202. Jstor. Web. 1 Mar. 2015. .
Harrington, E. 2004. “Napaeozapus insignis” (On-line), Animal Diversity Web. Accessed March 02, 2015 at https://animaldiversity.org/accounts/Napaeozapus_insignis/
Mockler, R. 2002. “Zapus princeps” (On-line), Animal Diversity Web. Accessed March 02, 2015 at https://animaldiversity.org/accounts/Zapus_princeps/

Author: Lauren Naylor

Calomyscidae is a relatively small family of brush-tailed mice containing 1 genus, Calomyscus, that includes 8 species and 11 taxa. These brush-tailed mice originated in the late Miocene and early Pliocene and were found throughout the Mediterranean into the Middle East. Now, they are found in rock piles and crevices on dry, rocky mountains, hillsides, and canyons of Iran, Afghanistan, and Pakistan. Morphological similarities suggested that Calomyscidae was closely related to the hamsters of Cricetidae and the New World mice of Neotominae, but recent studies including chromosomal analyses have placed brush-tailed mice as a distinct family of muroid rodents sister to the Muridae-Cricetidae-Nesomyidae clade. 

Brush-tailed mice are known for their large ears, small bodies, and tufted tails. Morphologically, each of the 8 species closely resemble each other, so much so that it took genetic investigation to disprove them as conspecific. They feed primarily on seeds, and very little is known of their communication patterns, breeding habits, or general behavior in the wild. While 6 of the 8 species are classified as Least Concern on the IUCN Red List, 2 species are notably Data Deficient. 1 of these 2, the Syrian Brush-tailed mouse, is possibly extinct. 

Author: Carson Hood

The Cricetidae family is the 2nd largest family of living mammals, consisting of 142 genera, 765 species, and 1505 extant taxa including true hamsters, voles, lemmings, and new world rats and mice. Fossil records and modern-day distributions on Laurasian continents and South America roughly date these rodents back to the Miocene-Pliocene boundary. Cricetid history is complexly interwoven with that of the Murids, so much so that previous phylogenetic classifications mixed the two families into a larger clade. This was a result of considerable morphological similarities, and molar design became an important distinguishing factor for the 2 families. The morphological characteristics of Cricetidae do vary, however they are typically small-bodied (although larger than murids) with most species uniformly colored on their darker dorsal and lighter ventral sides. Cricetids posess a large range of communication strategies, but the most notable are vocalization, stamping feet, and scent marking. Most cricetids are generalist omnivores, however their nearly global distribution and wide disparity provide ample exceptions. They are well known to be prolific breeders with short life spans and large litters. These rodents are terrestrial, although their habitats can range from belowground to the tops of trees with most living in shrubs and small trees. 

Within Cricetidae are 5 subfamilies: Cricetinae, Arvicolinae, Neotominae, Sigmodontinae, and Tylomyinae. Cricetinae includes 18 species of hamsters with significant popularity as both household pets and laboratory animals. Arvicolinae comprises 162 species of voles, muskrats, and lemmings with 10 tribes, and are famous for their particularly prolific population cycles. Neotominae makes up 4 tribes of 140 species of New World rats and mice, inhabiting mid-latitudes in North America. Sigmodontinae is the largest cricetid subfamily with 438 species primarily found in South America, with a few exceptions. Lastly, Tylomyinae contains 10 species of rats ranging from Southern North America to Northern South America. Human-cricetid interaction is typically negative, as many are vectors for disease and sources of crop damage, although their use in research studies have positively contributed to the well-being of humans. Most cricetids are considered species of Least Concern according to the IUCN Red List, however more data is needed to accurately assess their threats and necessary conservation measures.

Author: Carson Hood

The family Muridae consists of rats, mice, and their relatives from the Old World, and currently includes 5 subfamilies. These subfamilies further diversified into 150 genera and 730 species from multiple radiations that occurred in Asia during the Miocene, making it the largest mammal group. Genetic evidence indicates that these radiations resulted in the five lineages of murids. The first subfamily is Deomyinae, an African and Asian group that includes the spiny mice. The subfamily Gerbillinae, gerbils and relatives, is found in arid regions of Africa through the Middle East and into Asia. These small mice share many arid-adaptations with other mammals like kangaroo rats and jerboas. The subfamily Leimacomyinae contains only a single species, the grooved toothed forest mouse, from tropical Africa. The Otomyinae contains the whistling rats and vlei rats restricted to sub-Saharan Africa. Finally, the subfamily Murinae contains 561 species of which are generically called Old World rats and mice. Though current evidence supports these subfamilies, relations within Muridae continue to be evaluated. Members of Muridae are native to Australia, Europe, Africa and Asia, including parts of Micronesia, but are found worldwide, except for Antarctica, as commensals. Murids ,therefore, occupy a great diversity of habitats such as tropical forests, wetlands, and deserts and can be semi-aquatic, fossorial, or terrestrial. Diets also vary, as species can be herbivorous, omnivorous, or carnivorous.

Characteristics of murid skulls include an enlarged infraorbital foramen with a keyhole shape, a broad zygomatic plate, the lack of a postorbital process, and a sciurognathus lower jaw. In a sciurognathous jaw, the angular process and incisors begin at the same area. Each side of the jaw also includes one incisor each on the top and bottom rows, and does not include premolars. Most murids have three ever-growing molars. Shared physical characteristics include four claws on each front foot and five claws on the back feet. Other characteristics vary due to the different habitats populated by murids. Certain species of Muridae have historically carried diseases that devastate human and animal populations alike. Other species, however, maintain both insect populations and the quality of forests.

Work Cited
Myers, P. 2001. “Muridae Old World mice and rats, gerbils, whistling rats, and relatives” (Online). Animal Diversity Web. Accessed April 15, 2015 at https://animaldiversity.org/accounts/Muridae/
Michaux, J. et al. “Evolutionary History of the Most Speciose Mammals: Molecular Phylogeny of Muroid Rodents.” Mol Biol Evol 18.11 (2001): 2017-2031. Web. April 15, 2015. https://mbe.oxfordjournals.org/citmgr?gca=molbiolevol%3B18%2F11%2F2017
Vaughan, T.A., Ryan, J.M. and Czaplewski, N.J. 2015.Mammalogy, 6th edition. Jones and Bartlett Learning, Burlington, MA.

Author: xxx

Nesomyidae is a family of rodents nested in the superfamily of Muroidea and the suborder of Myomorpha. This family is composed of pouched rats, climbing mice, and fat mice all located in forests and savannas of sub-Saharan Africa and Madagascar. There are 21 genera, 68 species, and 76 taxa, including one species listed as critically endangered and seven listed as endangered. Since this family lacks unique morphological features, there has been debate about which families the subfamilies belong in. The first member of Nesomyidae discovered was Brant’s African Climbing Mouse, found in Africa in 1827. The last three genera were described in 1978 not from taxonomic changes, but rather from the recognition of new taxa. The first fossils came from the early Miocene of Kenya, Uganda, and Namibia. 

Although the morphological characteristics such as body form, locomotion, and dental characteristics widely differ in Nesomyidae, these species all share the same tooth enamel and tongue structure. The largest living animal in this family is the Southern Giant Pouched Rat, with males weighing from 1-2.8kg, and are characterized by a tail longer than the head and body length. The smallest living animal in this family is the Southern African Pouched Mouse, with an average weight of 50g and a tail one-third the length of its head and body. Both these species share large cheek pouches, as do all the members in Nesomyidae. 

Nesomyid rodents are nocturnal or crepuscular, and sleep during the day in underground burrows made of several chambers. These burrows consist of nesting areas, food storage, and escape holes and may be several meters in length. Studies of the burrows of Nesomyidae have found seeds, fruits, bulbs and tubers. While the communication of Nesomyidae has not been formally studied, there have been observations of vocal and olfactory communication in the wild. It is also speculated that members of Nesomyidae breed during the wet season, when food is abundantly available. Litter sizes are relatively small, with only around two or four young born at a time but can be as big as eight young. 

Most of the species of Nesomyids living in Africa are not threatened, but almost all the species living in Madagascar are listed as threatened. This is because these rodents live in forests, and Madagascar has lost over 40% of its natural forest cover. The Malagasy Government has taken action to increase protection of these habitats, and fortunately no native Malagasy rodent is known to be consumed as bushmeat by native people.

Author: Sidney Sanchez

The family Platacanthomyidae is comprised of small rodents. This family includes two species with two genera, Platacanthomys and Typhlomys. The two species are Platacanthomys lasiurus, Malabar Spiny Dormice, and Typhlomys cinereus, Pygmy Dormice. This family is found in southern India, southern China, and northern Vietnam. Overall, they have a discontinuous Old World distribution. Their preferred habitat is moist, rocky, tropical, and subtropical forests at an elevation of 600 to 2100 meters. Since Platacanthomyids are herbivores, they are primary consumers in their ecosystems. Their positive economic importance for humans is unknown at this time, but unfortunately this family does have a negative economic impact for humans. In India, the species Platacanthomys lasiurus is abundant and known as the pepper rat since it destroys pepper crops.

This family is known to be arboreal, scansorial, nocturnal, and motile. Commonly located near a stream, the Platacanthomyids occupy burrows, tree cavities, and clefts between rocks. The genus Platacanthomys uses their large, tufted tails to balance when hopping between branches. Overall, the platacanthomyids are mouse like in their appearance with a body length ranging from 70 to 212 mm. Their feet are slim and small with five medium long digits. They have naked feet that have six pads each. Skulls have a small and delicate dentary bone. Lastly, the species Typhlomys cinereus is critically endangered and listed on the IUCN Red List due to habitat destruction.

Work Cited
Poor, Allison. 2005. ” Platacanthomyidae ” (Online), Animal Diversity Web. Accessed January 26, 2015 at https://animaldiversity.org/accounts/Platacanthomyidae/ Updated September1, 2005

Author: Stacie Garcia

The family Spalacidae is part of the superfamily Muroidea, which contains five other rodent families including Muridae and Cricetidae. Ancestors of Spalacidae first appeared in Asia during the Oligocene, with the family later appearing in the Miocene. During this time, the spalacids spread out underground, where they developed into the three modern subfamilies. These subfamilies then further radiated to their current locations. Spalacidae includes 3 subfamilies and 6 genera, which together include 36 species. The subfamilies are Myospalacinae including the genera Myospalax and Eospalax, Rhizomyinae including the genera Cannomys and Rhizomys, and Spalacinae including the genera Spalax. Species within the Spalacidae family include such animals as the zokors. Previously, Tachyoryctinae was a fourth subfamily, but recent molecular research has shown that the genus Tachyoryctes is in fact a sister group of Rhizomys, and has thus been incorporated into the subfamily Rhizomyinae.

Members of Spalacidae are found all throughout the Old World. Specifically, spalacids are found from Western to Eastern Europe, East Africa, the Middle East, and from China to Sumatra in Asia. Spalacids are either fossorial or semi-fossorial, and burrow in areas with damp soil, typically in grasslands or savannah. Members of Spalacidae are small to medium-sized rodents and have robust bodies, small eyes and limbs, and enlarged incisors. Though some species are naked, most members have a think coat of fur. The large front teeth serve as the primary mechanism for burrowing in all members except those belonging to Myospalacinae, which utilize limbs to dig underground. In addition to large incisors, spalacids also have hypsodont dentition, which indicates an herbivorous diet. Sexual dimorphism is not seen in most species. However, some species such as Tachyoryctes splendens exhibit larger males than females. In addition to large incisors, certain Spalacids have developed other adaptations to a subterranean lifestyle. Members of the genus Spalax have tumor suppressors that counteract cell death, which can occur when the body receives little oxygen. These tumor suppressants have been found to prevent and halt cancer development in organisms. Research is currently being conducted to find possible drug applications of these suppressants.

Work Cited
Honeycutt, R. et al. “The phylogenetic position of the zokors (Myospalacinae) and comments on the families of muroids (Rodentia).” Molecular Phylogenetics and Evolution 31.3 (2004): 972-978.
Poor, A. 2005. “Spalacidae blind mole rats, African mole rats, zokors, and bamboo rats” (Online). Animal Diversity Web. Accessed March 29, 2015 at https://animaldiversity.org/accounts/Spalacidae/.
Lin et al. “Transcriptome sequencing and phylogenetic resolution within Spalacidae (Rodentia).” BMC Genomics 15.32 (2014).
Manov et al. “Pronounced cancer resistance in a subterranean rodent, the blind mole-rat, Spalax: in vivo and in vitro evidence.” BMC Biology 11.91 (2013).

Author: Anna Cole

The Aplondontiidae family consists of one species Aplodontia rufa, the mountain beaver. Mountain beavers have no close relation to the North American beaver. This family extends back to the Miocene, with the genus Myagaulidae being an extinct member. The family can be found in the Nearctic Region, from central California to southern British Columbia. They are found from sea level to the tree line in high mountain peaks within the deciduous and coniferous forest, primarily in moist habitats. Aplodontia are large rodents that weigh approximately 1.5 kg with short tails and coarse dull, fur. This family vocalizes with booming and whistling sounds; when fighting they squeal and grind their teeth to make noise.

They live in complex burrows with openings that are covered with vegetation or sticks. The burrows have interconnecting tunnels that lead to chambers used for denning, feeding, and storage of food, fecal pellets and refuse. They spend around 75 % of their time inside the burrows only moving around to areas of close proximity to their burrows (Zielinski et. al 2010). Although they are not a social species they often build their nests in concentrated colonies with overlapping territories; there they defend their burrows from other individuals. From the close proximity of their burrows, these herbivores feed on forbs, grasses and ferns; while feeding the mountain beaver re-ingests their soft fecal pellets by catching the excreted pellets into their mouths, a process known as coprophagy.

Work Cited
Myers, P. 2000. “Aplondontiidae” (Online), Animal Diversity Web. Accessed November 23, 2014 at https://animaldiversity.ummz.umich.edu/accounts/Aplodontiidae/
Zielinski, W.J., J.E. Hunter, R. Hamlin, K.M. Slauson, and M. J. Mazurek. 2010. Habitat Characteristics at Den Sites of the Point Arena Mountain Beaver (Aplodontia rufa nigra). Northwest Science 84:119-130.

Author: Rebecca Mendez

Gliridae branches into 3 subfamilies that contain 9 genera and 29 species of dormice. Originating in the early Eocene around 50 million years ago, glirids are some of the oldest living rodents. Although this family has survived multiple extinction events, they weren’t unaffected. Where they were once rich in taxonomic diversity, the few remaining extant species are now seen as ‘living fossils’ due to the dramatic reduction in number of species. The largest subfamily, Graphiurinae, is made up of 1 genus and 15 species of African dormice that are thought to have colonized Africa in the late Miocene. Glirinae only contains 2 species and are considered relics of past adaptive radiations. Lastly, Leithiinae contains 12 species of Palearctic dormice marked by an early divergence from the other subfamilies 24-33 million years ago. 

With a common name derived from the Latin word ‘dormire’ meaning ‘to sleep’, these rodents use their ability to hibernate to survive a range of diverse habitats in Palearctic and Afrotropical regions. They are small to medium-sized, all with non-prehensile tails, large eyes, and rounded ears. All extant species are omnivorous, and, interestingly, dormice are the only rodents that lack a cecum. Glirids communicate via common methods of rodent communication, such as vocalizations or scent marking, however their meaning has not been entirely understood despite many attempts. The greatest threats to dormice are deforestation and a reduction in habitat due to human influence.

Author: Carson Hood

The Sciuridae family comprises 60 genera, 292 species, and 1040 taxa of herbivorous tree, flying, and ground squirrels, chipmunks, marmots, and prairie dogs. These rodents have a period of origin of roughly 36 million years ago, and a natural distribution across all continents except Australia and Antarctica. Molecular evidence suggests 5 subfamilies within Sciuridae: Ratufinae, Sciurillinae, Sciurinae, Callosciurinae, and Xerinae. Ratufinae, the largest living squirrels, contains 4 extant species of giant tree squirrels. Sciurillinae is comprised of a single extant species, the small, yet loud and conspicuous Neotropical Pygmy Squirrel. 89 species of tree and flying squirrels are included in Sciurinae, the only subfamily of Sciuridae with species that exhibits nocturnal behavior. Callosciurinae has had some minor taxonomic controversy but updated molecular genetic data has proven its 67 species of south-eastern Asian tree and striped squirrels are aptly placed. The last subfamilty, Xerinae, includes all 131 species of ground-dwelling squirrels of Africa. 

Morphologically, this family sees substantial variety in both pelage color and body size. Prominent ever-growing incisors and a well-developed jaw, in addition to the widely known bushy tail on most, are common physical markers for Sciuridae. These rodents have proven to be a model clade for genetic studies due to their large distribution, historical and species diversity, and behavior. Communication-wise, sciurids have well-understood methods of vocalization that are more descriptive than many known rodents, such as the case of Prairie Dogs encoding elaborate details of nearby predators in their calls. The biggest threat to members of Sciuridae is, short-term, habitat loss, and, long-term, climate change. Although this diverse family has been able to keep up with a changing environment for millions of years, a quarter of all members of Sciuridae are facing population declines. Collecting more data on these species is crucial for their conservation. 

Author: Carson Hood