During my 7-week internship with the IUCN SSC Small Mammal Specialist Group, I acquired invaluable experience and knowledge in the fields of small mammal conservation and research. My primary responsibility was to create a field guide dedicated to Sulawesi’s small mammals, a significant outcome of the Sulawesi workshop held in May 2023. This task involved meticulously compiling resources from red list assessments and articles to develop up-to-date species profiles for Sulawesi’s endemic rodents and shrews. Additionally, I generated range maps for each species, enhancing my proficiency in R programming. I also participated in the review process of an article intended for publication, and was tasked with seeking funding opportunities to support the publication of the field guide. I am grateful for the opportunity to contribute to a resource that will directly benefit researchers and students in Sulawesi.
Prior to this experience, having just completed my undergraduate degree, I held the belief that academia was the sole avenue for pursuing a career in biology. However, this internship has broadened my perspective, revealing that roles involving research and conservation need not be mutually exclusive. Moreover, it has provided me the opportunity to establish valuable connections that will be undoubtedly beneficial for my future career in conservation. Finally, I would like to express my gratitude to Ros and Abi, whose support and warm welcome into the organisation have made this internship a truly enriching experience.
Imagine a feathery-tailed, round rabbit-like creature munching on grasses in the mountains of Patagonia. This is Wolffsohn’s ViscachaLagidiumwolffsohni, and despite possessinglong, rabbity ears, viscachas are actually rodents, most closely related to chinchillas.
Wolffsohn’s Viscacha: Dario Podesta
There are five extant species of viscacha, all native to South America. Wolffsohn’s Viscacha – officially described in 1907 after J.A. Wolffsohn donated several specimens to the British Museum – is known from theSierra de los Baguales mountain range crossing southern Argentina and Chile. Viscachas are found across a variety of elevations, favouring rocky cliffs and outcrops. As zoologist Pearson (1948) once put it: “no rocks, no viscachas”.
Wolffsohn’s Viscachas prefer very steep areas where they have been observed living in colonies and reproducing only once annually (or potentially even less). However, not much else is known about this species. On the IUCN Red List, it remains categorised as Data Deficient.
Between a rock and a hard place
Being listed as Data Deficient does not mean that Wolffsohn’s Viscachas are without threat. This species was historically hunted for fur and food by the first inhabitants of Patagonia, and may still be occasionally hunted today. It could also be vulnerable to climate change and the associated impacts upon habitat availability. Other species of viscacha, such as the Southern Viscacha Lagidium viscacia, are reported to be threatened by disturbance, habitat loss and fragmentation, and some colonies are nowadays restricted to isolated patches.
Quantifying the threats and population trends of Wolffsohn’s Viscachas will be key to updating and understanding the conservation status of this species. This is a knowledge gap that one of the SMSG’s newest members, Morgan Pendaries, is hoping to fill. Morgan is working on a PhD project that will gather ecology, demographic and threat data of Wolffsohn’s Viscacha.
Working with Wolffsohn’s Viscacha. Left: Morgan Pendaries. Middle, right: Gonzalo Pardo.
Conducting the research alongside Programa Patagonia, Morgan has been carrying out viscacha surveys since 2018. “What I really enjoy about the work after 5 years of study is going to the field and observing the viscachas,” Morgan says. “They are such a gorgeous and curious species that I’m always really happy to just observe them.”
The work involves capture-mark-recapture surveys as well as efforts to gather data on the social dynamics of a colony, habitat use and interactions with other wildlife. Interviews with local people are also an important element – Morgan and the team want to learn more about viscachas using local knowledge, but also understand public perceptions of these animals.
Morgan’s work will ultimately help to inform the Red List reassessment of Wolffsohn’s Viscacha and, if needed, drive conservation plans forward for this species. In the meantime, we are looking forward to reading any future research updates on this unusual, rabbity rodent!
Sulawesiis a large mountainous island in Indonesia that lies adjacent to the Wallace Line.It’s a hotspot of diverse and endemic fauna,and unique in the sense that it hosts species of both Asian and Australasian origins – there’s nowhere else quite like it.
In a recent study, the IUCN SSC Small Mammal Specialist Group (SMSG) highlighted Sulawesi as a key region because of its particularly high number of globally threatened and data deficient rodents. However, it’s not just rodents that Sulawesi is particularly rich in. Since that study, at least 14 new shrew species have been formally described from the island. With numerous newly discovered species remaining unassessed on the IUCN Red List, or already-known species lacking up-to-date assessments, the conservation status of Sulawesi’s rodents and shrews is somewhat uncertain.
And so, in May 2023, theSMSG set out to address some of these gaps by hosting the Sulawesi Small Mammal Workshop.
We started off by applying this knowledge to the Red List assessments which, with 76 species to get through, was no easy feat. The workshop then opened up a discussion of important priorities for Sulawesi’s small mammals. Participants highlighted key research and conservation goals, and we began to identify ways in which we can implement these – we’ll be bringing more updates on this later!
The next steps for the SMSG and workshop attendees will be to submit the updated Red List assessments for publication, work on capacity-building for Sulawesi’s scientists and NGOs through, for example, developing projects on the ground, and also to create outputs such as a workshop report and small mammal field guide. It is hoped that through this work we can help to push small mammal priorities forward in Sulawesi. Watch this space!
A selection of Sulawesi’s small mammal taxa. Photos from Kevin C. Rowe, CC BY 4.0.
Long-tailed Sulawesian Shrew Rat (Tateomys macrocercus)
You might think you have the measure of the rodent family. Perhaps just the word “rodent” conjures images of invasive rats, those urban denizens accused of spreading pathogens and parasites, chewing through wires and spoiling food.
Most rodents are, in fact, more elusive and inhabit quiet corners of rainforests, mountains, deserts and rivers. These small mammals have filled a niche in nature for at least the last 56 million years, and from shrew-rats to true rats and hamsters to beavers, rodents play an important role in ecosystems worldwide.
Yet, a huge number of rodent species are on the brink of extinction. Eking out an existence in shrinking habitats and under threat from persecution, pollution and climate change, rodents are overwhelmingly neglected by research and funding that might help to protect them. We are three conservation scientists determined to show that this is a mistake – and change your mind about these misunderstood creatures.
Dormice can hibernate for six months or longer. Slowmotiongli/Shutterstock
More than vermin
Roughly 40% of all mammal species are rodents. There are around 2,375 living species, spanning mice, rats, squirrels, hamsters, voles, porcupines, lemmings, beavers, chinchillas, chipmunks and more. The number of recognised rodent species is still growing and at a seemingly faster rate than other mammal groups including bats, primates and carnivores. Between two comprehensive checklists of global mammal species produced in 2005 and 2018, an additional 371 rodents were officially recognised.
New discoveries are often the result of genetic work that has identified multiple similar-looking species previously described as one. Nonetheless, from the 3g desert-dwelling jerboa to the 50kg semiaquatic capybara, rodents are a remarkably diverse bunch.
This diversity allows rodents to play numerous roles in Earth’s ecosystems. Rodents have a hand (or rather, paw) in determining which plants propagate and where by eating and dispersing their seeds. Beavers engineer entire ecosystems with their dams which help to purify water systems and moderate floods and droughts, while burrowing kangaroo rats create subterranean habitats used by other wildlife. Rodents are also an invaluable link in the food chain, sustaining predators which include birds of prey, wolves, snakes and even spiders.
We shouldn’t forget that humans have long benefited from relationships with rodents. Agoutis in South America are one of the few animal groups capable of cracking open the capsules of the Brazil nut fruit. By hoarding excess seeds, agoutis help disperse their trees throughout the Amazon rainforest and support the global production of Brazil nuts, which is almost entirely dependent on wild harvests. African giant pouched rats can detect tuberculosis in saliva, hidden land mines, survivors trapped under rubble and pangolins smuggled in shipping containers. By studying the resistance of naked mole-rats to cancer, scientists hope to improve our understanding of the disease and its potential treatment. It’s clear that the loss of a rodent species – even the smallest – can have cascading consequences for humans and the environment.
A grizzled giant squirrel, native to Sri Lanka. Martin Mecnarowski/Shutterstock
Underfunded, understudied and disappearing
Worryingly, at least 15% of rodent species are threatened with extinction. More than 100 are among the top 560-ranked Evolutionarily Distinct and Globally Endangered (EDGE) mammals, meaning that while they are threatened, they also have few or no close relatives. If an EDGE species were to disappear, there would be nothing really like them left.
For many more species, scientists simply don’t know enough to understand how they are faring: the population trend (whether they are stable, declining or increasing) of at least a thousand rodents is unknown. Even when it comes to zoonotic disease, there are substantial gaps in our knowledge of viruses in rodents and how outbreaks might be influenced by their ecology or population dynamics. The reality is that rodents receive very little scientific attention beyond their discovery and naming.
Rodents are a hard sell outside science too. Studies on the public perception of wildlife demonstrate that rodents are generally the least favoured group. Compared to larger-bodied mammals, rodents and small mammals are referred to on Twitter substantially less, not considered as interesting by zoo visitors and inspire fewer donations to conservation schemes. Even the bigger rodents such as beavers are outranked by large carnivores, birds, moths and bees in public preference surveys.
It is no surprise then that some species have already fallen through the cracks. The little Swan Island hutia, a rodent once endemic to Caribbean islands of the same name, was driven to extinction in 1960 by introduced cats. The Candango mouse disappeared during a similar period in central Brazil, where its forest habitat was almost entirely paved over. Australia’s Bramble Cay melomys was declared extinct as recently as 2016 after rising sea levels gradually degraded the tiny coral island on which it lived. The loss of this rodent is thought to be the first modern mammal extinction caused by climate change.
Some rodents remain unstudied for so long that it’s not known whether they still exist. Gould’s mouse, a species also native to Australia, was thought to be extinct for 150 years before it was recently rediscovered surviving on islands off of western Australia. Another, the Namdapha flying squirrel, was thought to be extinct in the wild until a single specimen was collected in 1981 from northeast India. The species is now listed as critically endangered and is currently known only from informal sightings dated decades ago. Of the world’s rediscovered species, the data shows that rodents remain missing for the longest time, probably because there are not enough people looking for them.
Even well-monitored or well-known rodents aren’t safe. The common hamster is listed as critically endangered, and could die out in coming decades unless its decline is reversed. Its popular pet cousin, the golden (or Syrian) hamster, is also endangered in the wild, clinging on to its last fragment of habitat.
Many rodents can adapt well to landscapes altered by people, but others cannot adjust to this rat race and exist only in dwindling and deteriorating wildernesses. It is likely that we have already lost many species which we never even knew existed.
The first step towards recovering many threatened yet overlooked species may be to alter our own perceptions and behaviour. For the little guys like rodents, this means appreciating that even though they are perhaps not as glamorous or mighty as many flagship conservation species, we are far more dependent on their biodiversity than we might imagine.
Baer’s Wood Mouse (Hylomyscus baeri) has been scarcely studied. It was officially described in the 1960s but is still only known from a few localities in West Africa. This species is listed as Endangered in the most recent IUCN Red List assessment, given that it has only been found in small area where it is declining in number and losing habitat.
This distinctive, tawny brown mouse is larger than its more common cousin, the West African Wood Mouse (H. simus), with a white underbelly bordered with a yellowish line of fur, long slender tail and comparatively large eyes and ears. It has only been formally recorded a handful of times in Ghana and Côte d’Ivoire, with single records also known from Sierra Leone and Guinea. It has been found in secondary forest, forest edge and plantations and, more recently, swamp forest. We know little more about this species’ ecology or life history.
Baer’s Wood Mouse depicted in Wilson et al. 2017.
We are pleased to report that SMSG member and conservation scientist Prince Adu-Tutu has been awarded a Rufford Foundation grant to study Baer’s Wood Mouse in Ghana and start to fill some of the gaps in knowledge. Prince’s project has 3 primary objectives to:
estimate the population and distribution of the Baer’s Wood Mouse,
identify the major threats and drivers to the Baer’s Wood Mouse and its habitat, and
launch a conservation education and awareness campaign in selected fringe communities to enhance understanding of the Baer’s Wood Mouse, threats to the forest habitat and the value of biodiversity.
From left to right: Researcher Prince Adu-Tutu; survey team with forest guide; setting up a Sherman trap. Source: Prince Adu-Tutu.
From early next year, Prince will be conducting his fieldwork with a team of colleagues from two local NGOs in Ghana:EcoWild Conservation and the Institute of Nature and Environmental Conservation. Once accessible sampling sites have been identified within two southern forest reserves, Prince will be deploying a series of Sherman traps to measure small mammal presence in the area.
Unfortunately, the reserves are under threat of deforestation for agriculture and illegal logging. Many small rodents are further at risk from people where they may be perceived either to be a nuisance, or a source of food. With his awareness campaign, Prince therefore hopes to reinforce the importance of these reserves for rare species such as Baer’s Wood Mouse, and hopefully help to stimulate greater interest in rodent conservation.
Santa Catarina’s Guinea Pig (Cavia intermedia) has the smallest geographical distribution of any known mammal. It occurs on a 10-ha island within the coastal archipelago of Moleques do Sul in Santa Catarina State, Brazil. This small, scrubby island is home to a few handfuls of guinea pigs, and has been for thousands of years.
It is thought most likely that Santa Catarina’s Guinea Pig descended from another guinea pig, C. magna, inhabiting the nearby Santa Catarina coastline. The guinea pigs became isolated on Moleques do Sul probably when rising seas formed the archipelago some 8,000 years ago. Since then, relatively little has changed. The island hosts no significant predators, competitors or humans, and its supply of food for herbivores is plentiful – a perfect scenario for the guinea pigs.
Despite their small numbers, the Santa Catarina’s Guinea Pig population might in fact be considered stable – it is highly possible that numbers have remained unchanged for centuries. Such a small population, nevertheless, is extremely vulnerable to chance events that could have a critical impact on the species. Insular rodent populations in the past have fallen victim to pathogen introduction or rising sea levels. For the guinea pigs, additional threats include fire, poaching and general human disturbance; the island is sometimes accessed illegally by fishermen who station themselves there overnight.
Surveying and safeguarding island guinea pigs
Camera on Moleques do Sul
Santa Catarina’s Guinea Pigs have scarcely been studied. They were discovered only a few decades ago and, since then, any effort to monitor them has been made difficult by the limited accessibility to the archipelago. One researcher, however, is committed to conserving this species.
Brazilian biologist Dr Carlos Henrique Salvador is the Small Mammal Specialist Group’s Key Species Champion for Santa Catarina’s Guinea Pig. Carlos led the initial project to survey the guinea pigs in 2004-2005 and is today working on monitoring the current population using a network of trail and security cameras, which were kindly funded by a Greensboro Science Center (GSC)grant. After testing the sampling design, the data gathered will ultimately be used to investigate things such as population size and feeding areas.
Captured by a Greensboro Science Center-funded camera trap
“The general goals are to monitor the species remotely, its habitat, and illegal use of the island by humans,” explained Carlos. “We have over 1 terabyte of images to process from the first sampling period. However, the island conditions make it difficult for deploying and running electronic devices, and adjustments will need to be made for future sampling rounds.”
In recent years, Carlos and his colleagues have also published a species action plan for Santa Catarina’s Guinea Pigs. The action plan focuses on increasing monitoring efforts – which have of course been initiated – and also deals with how to protect the island from illegal use whilst raising more awareness of this species.
It is hoped that such conservation and monitoring efforts will be enough to keep the population safe and stable. Although it may be the rarest rodent in the world, Carlos says “I am optimist, and I believe we can mitigate the risks posed to Santa Catarina’s Guinea Pigs.”
Check out some of the footage captured on one of Carlos’ GSC camera traps below!
Author: Abi Gazzard (SMSG Programme Officer)
Images & video: Carlos Henrique Salvador & Tabuleiro Institute
The Small Mammal Specialist Group (SMSG) is happy to report the recent publication of a paper in the open-access journal Diversity detailing the process, and results, of species prioritization exercises for conservation planning and action. The exercises were carried out by the SMSG as well as a second IUCN SSC specialist group, the Antelope Specialist Group(ASG).
Given the limited resources and finances available in conservation, strategically determining which species to focus on can be the most fair and effective way to guide conservation efforts. But how do we do this? Simply selecting species based on the level of threat they face, for example, ignores the importance of functional and phylogenetic diversity.
It can therefore be helpful to use systematic prioritization methods that incorporate multiple criteria. Previous examples have included the ranking of species based on e.g., the cost and logistics of a project, the likelihood of conservation success, and/or metrics of species value, such as their status as an umbrella species, evolutionary distinctness, or cultural significance. Sometimes, these criteria are assigned different weightings depending on their relative importance. There exists no universal method for selecting and using such criteria, however.
Selecting small mammals
For large taxonomic groups such as small mammals (encompassing over 2,800 rodents, eulipotyphlans and tree shrews), prioritization approaches are invaluable in identifying how to best allocate already-stretched conservation resources. As such, in 2018, the SMSG developed and undertook a species prioritization exercise in Mexico. Mexico had been previously highlighted as a region with high aggregations of both globally threatened and data deficient small mammals.
Mexico species prioritization workshop
Experts in Mexico first undertook a high level review of the Red List status of each of the 76 small mammal species found in the country. Those identified as Critically Endangered were then assessed against variables such as threat status, the proportion of a population falling within protected areas, and extent of existing captive breeding or conservation management efforts. Species were then scored based on urgency of conservation action, feasibility (i.e., the capacity to implement conservation action and research), and the number of other threatened small mammals that would also benefit from conservation action for said species.
The top six species identified were those with the highest scores – all were rodents with highly restricted ranges, three of which are found only on islands (Cozumel Harvest, Catalina Deer and Angel Island mice). Based on these scores, draft action plans have since been developed and channeled into attempts to secure conservation funds. Proposals for the Cozumel Harvest Mouse and Angel Island Mouse have, however, been unsuccessful, something which the authors describe as “a recurring difficulty in supporting rodent conservation”.
Nevertheless, the Diversity paper sets out a framework that proved to be effective in selecting species to prioritize. It also underlines the importance of participation from regional experts; without local expertise, the feasibility of working on particular fauna can be misjudged. Some species, for example, might occur in regions where local experts know that opportunities to conduct field research or conservation activities are limited by economic or safety considerations.
One of the top 6 species: Magdalena Rat
Overall, the framework jointly developed by the ASG and SMSG was successfully fed into prioritization exercises for the respective groups, with the results leading to new proposals and increased interest in certain species of conservation concern. The framework will be applied again in future workshops; for small mammals, there are plans to conduct a similar assessment in Sulawesi later this year.
The chinchilla, a small,nocturnalSouth American rodent, has previously been pushed to the brink of extinction for its prize fur.It is now protected from hunting but remains at risk as demand increases for another high-value product – gold.
The two species of chinchilla (the long-tailed Chinchilla lanigera and the short-tailed Chinchilla chinchilla) were once widespread across the coastal regions and foothills of the Andes in Chile, Peru, Argentina and Bolivia. Commercial hunting for fur drove their numbers down dramatically from the 19th century, and at one point, half a million skins were being exported per year. A ban on hunting in 1929 increased the value of their fur even more and intensified demand. By the mid-1900s, it was thought that chinchillas had been hunted to extinction.
Fortunately, C. lanigera and C. chinchilla populations were rediscovered in northern Chile by the turn of the century, and a colony of C. chinchilla was additionally found in Bolivia in 2017. However, the rediscovered chinchilla populations are small and isolated – chinchillas live in colonies made of modest family groups, hundreds of kilometres away from the next. Numbers continue to decline and, currently, they are listed as Endangered on the IUCN Red List.
Sitting on a gold mine
Camera trap images of long-tailed chinchillas. Source: Amy Deane.
In addition to poaching and habitat loss associated with agricultural and grazing activities, mining has become a substantial threat to chinchillas. Multiple colonies in Chile are known to be living on top of huge quantities of extractable gold.
According to the Chilean government’s national chinchilla conservation plan, mining activities lead to the loss and degradation of habitat, and directly impact individuals or colonies through noise or vibration disturbance, death or displacement of individuals, and loss of food resources.
Amy Deane, who is a member of the Small Mammal Specialist Group and founder of Save The Wild Chinchillas, has stressed that gold mines pose a grave threat, particularly given the slow reproductive rate of this species (one or two young are produced per litter, once or twice a year).
“Both species of wild chinchillas are paper protected, meaning that they are protected by laws and treaties,” says Amy. “However, the reality is that their protection in disputed areas, such as mining concessions, is continually under threat, and there is growing pressure to ease some of the restrictions safeguarding those populations.”
Challenges for chinchilla mitigation
Effort has been made to mitigate the impact of mining developments on chinchillas by translocating individuals out of sites earmarked for gold extraction. However, these attempts have not yet been successful: in northern Chile, at a site owned by the company Gold Fields, translocation plans were halted in 2020 after two of four relocated chinchillas died in a soft-release enclosure and a third was found injured. This might have been down to acute stress caused by a disruption to the chinchillas’ social structure, handling procedures and movement to a new site.
Such negative outcomes are not unusual in small mammal translocation attempts (e.g. Matějů et al. 2010; Tennant and Germano 2017, Rayner et al. 2021). Some rodents, for example, have shown high levels of homing behaviour when relocated short distances from their original range, and increased mortality when translocated over larger distances. Strong justification is therefore needed for translocation projects and, at the very least, there should be sufficient species knowledge to inform such projects.
Case studies of chinchilla translocations are unfortunately lacking. In fact, relatively little is known about the basic biology of these animals. Without this fundamental information, it’s not clear how mining developments will move forward, only that they are indeed expected to move forward: Gold Fields intends to commence gold production when construction is completed later this year.
It is not yet known whether the government will be allowing further translocation attempts or pushing for alternative mitigation measures. In the meantime, Amy and her colleagues at Save The Wild Chinchillas are working hard to spread awareness of the plight of the chinchillas, and to find a way to ensure the protection of the dwindling colonies that live atop unmined gold.
The annual British and Irish Association of Zoos and Aquariums (BIAZA) awards celebrate the achievements of zoo associations in fields such as Education, Conservation and Research. This year, Durrell Wildlife Conservation Trust has received a silver BIAZA award for research exploring global hotspots of, and research priorities for, the world’s Rodentia and Eulipotyphla.Theproject titled “Scaling up small-mammal conservation: setting global priorities for understudied and overlooked species”, was led by the Small Mammal Specialist Group (SMSG) with partners at Durrell – who host the SMSG Co-Chair and Programme Officer roles – as well as Texas A&M University, the Zoological Society of London and Re:wild.
Small mammals exhibit remarkable functional, morphological and phylogenetic diversity. They include some of the world’s most primitive mammal taxa and can be found in virtually every terrestrial ecosystem. Yet, despite this, they are frequently overlooked in conservation science: research confirms that the poorly studied and largely ignored mammal species are those present in countries with limited scientific capacity, those that have been described only recently, or those that are small in size.
The SMSG’s award-winning project has therefore been an important step forward for the small mammal field. Using information gathered from the IUCN Red List, the aim of this project was to identify small mammal hotspots across the globe where conservation actions could have the greatest impact. The work focuses on the orders Eulipotyphla (e.g. hedgehogs, shrews, moles and solenodons) and Rodentia (e.g. rats, mice, squirrels, beavers and porcupines) which, together, make up nearly half of all living mammal species.
In total, 76 of 454 known eulipotyphlan species and 324 of 2,231 known rodent species are classified as globally threatened on the IUCN Red List. By analysing the distribution and richness of these groups, multiple hotspots were identified: for eulipotyphlans, three regions (Sri Lanka, Western Ghats and Cameroonian Highlands) were found to contain disproportionately more at-risk species than expected. For rodents, six regions (in Mexico, Cameroonian Highlands, Southwestern Ghats, Sri Lanka, Malaysia and Indonesia) are inhabited by disproportionately more at-risk species than would be expected.
The researchers further reported that much of the globe’s small mammal diversity does not fall within protected areas. Protected areas are considered “the single most important conservation tool” yet are very rarely set up with small mammals in mind. In fact, five eulipotyphlans and 44 rodents were found to occur in regions completely outside of any protected site.
The study additionally highlighted regions with the highest numbers of ‘data deficient’ small mammals, i.e. species for which insufficient population or distribution information is available to make a Red List assessment. These areas – within Central and South America – require urgent research attention.
Moving forward, the SMSG have used these results to inform action on the ground. The SMSG recently hosted a small mammal workshop in one of the identified priority regions, Mexico, with plans to replicate this in more key regions in the future. Such workshops bring together experts from government, academia, NGOs and other stakeholders, facilitating the development of prioritisation methods and species action plans.
The recognition of this work in the BIAZA annual awards is a great achievement for the SMSG and shines a light on the group’s contributions to raising the profile of, researching and conserving small mammals – congratulations to everyone involved!