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Today, 4th April, is World Rat Day, so what better day to celebrate some of the world’s most diverse and fascinating mammals? 

The first thing that springs to mind with the word “rat” might be the widespread and recognisable Brown Rat (Rattus norvegicus). In actual fact, “rat” is a broad term that has been used to describe hundreds of species of muroid rodents. The name “rat” typically covers the true rats of the Rattini tribe (including, for example, species of the Rattus genus), but has also been used in common names for groups such as the kangaroo, mosaic-tailed, spiny, mole and rabbit rats.  

Native rats play key roles in ecosystems everywhere. They are scatter-hoarders, scavengers, burrowers, predators, and prey. However, lacking the obvious characteristics of larger flagship mammals, most rats are completely overlooked and underrepresented in the media, as well as in funding, conservation and research.  

Below, we are spotlighting some of these remarkable yet at-risk rats. 

Yesterday, we reported on the IUCN Red List’s first update of the year (27th March 2025) and some of the small mammal Red List assessments it included. Today, we are highlighting the four Green Status of Species assessments also included in this latest update. The IUCN Green Status of Species complements the Red List by providing a tool for assessing the recovery of species’ populations and measuring their conservation success. Green Status assessments are published on the Red List website, and provide insight into how current and future actions could contribute to species’ conservation.

Menzbier’s Marmot (Marmota menzbieri) – Critically Depleted 

Restricted to the western part of the Tien Shan Mountains in Kazakhstan, Kyrgyzstan and Uzbekistan, Menzbier’s Marmot was assessed as Vulnerable on the Red List in 2023. The Red List team for this species – comprising species experts Ormon E. Sultangaziev, Elena Bykova and Aleksandr Esipov, and the SMSG’s Programme Officer Abi Gazzard – then decided to embark of the Green Status assessment process. In the assessments, we report that Menzbier’s Marmot is threatened by the rapid loss of alpine and subalpine meadow habitats, livestock herders’ dogs, poaching, mining, quarrying and climate change. Unfortunately, its Green Status assessment shows a low Species Recovery Score of 13% (Critically Depleted). This is because the species is recorded as Critically Endangered and Endangered in two of its distinct populations, and absent in the third unit of its former range. Human population growth, and increased infrastructure and livestock to support it, is expected to soon impact higher elevations, where the species’ range has begun to shift in response to climate change.

Bykova, E., Esipov, A., Gazzard, A., Plakhov, K. & Sultangaziev, O.E. 2024. Marmota menzbieri (Green Status assessment). The IUCN Red List of Threatened Species 2024: e.T12827A1282720251.

Calabrian Black Squirrel (Sciurus meridionalis) – Moderately Depleted

The Calabrian Black Squirrel was assessed as Near Threatened as part of the European Red List Pulse project in 2024. Now, in the latest update, its Green Status assessment shows a score of 52%, placing it in the Moderately Depleted category. In the long-term, reforestation efforts combined with enhanced habitat management, restoration of habitat connectivity, and captive breeding to improve genetic variation have the potential to move the species into the Slightly Depleted category, reflecting a Medium Recovery Potential. This assessment was coordinated by Durrell intern Salomé, who worked closely with Assessors Giovanni Amori and Gaetano Aloise, following Giovanni’s efforts on the 2024 Red List assessment.

Amori, G. & Aloise, G. 2024. Sciurus meridionalis (Green Status assessment). The IUCN Red List of Threatened Species 2024: e.T221730662A22173066220251.

North American Beaver (Castor canadensis) – Slightly Depleted

The SMSG’S Deputy Chair for Eulipotyphla, Alexis Mychajliw, has co-assessed two North American native species in recent months. First up is the North American Beaver which, whilst Least Concern on the Red List, is reported as Slightly Depleted on the Green Status of Species with a species recovery score of 83%. It is considered fully Functional in three of the six spatial units within its indigenous range, and Viable (but not Functional) in the remaining three. Trapping regulations and translocations have helped conserve this species and, without these interventions, it is estimated that the Recovery Score would be as low as 44%. This is a great example of how Green Status assessments can capture the impact that past interventions have had.

Snyderman, L.S., Mychajliw, A. & Hofman, C.A. 2024. Castor canadensis (Green Status assessment). The IUCN Red List of Threatened Species 2024: e.T4003A400320251.

Common Muskrat (Ondatra zibethicus) – Moderately Depleted

Last is the Common Muskrat, prepared by the same team as above. This is a Least Concern species, yet its Green Status assessment highlights how the status of existing populations is somewhat reliant on trapping regulations. The removal of these regulations would be detrimental to the species. Improvements in habitat quality and connectivity could further increase its species recovery score in the long-term, which currently stands at 67%.

Snyderman, L.S., Mychajliw, A. & Hofman, C.A. 2024. Ondatra zibethicus (Green Status assessment). The IUCN Red List of Threatened Species 2024: e.T15324A1532420251

The IUCN Red List of Threatened Species has just published its first update of the year (27th March 2025), including reassessments for many small mammal species submitted by the Small Mammal Specialist Group. This time around, most species stayed in the same category, with a handful moving to less threatened categories. Read about some of these species below.

Dusky Hopping-mouse (Notomys fuscus) – Near Threatened 

First up is this mouse found in Australia, which has been downlisted from Vulnerable to Near Threatened in the latest update. Despite the large historical declines in abundance and distribution, this is a good news story. Increases in the range and populations have been recorded in recent decades, due to effective control of invasive European Rabbit (Oryctolagus cuniculus), which had the knock-on effect of lowering cat (Felis catus) and red fox (Vulpes vulpes) numbers as they were no longer being sustained by high rabbit availability.

Photo credit: Boyd Essex, Wikimedia.

Wimmer’s Shrew (Crocidura wimmeri) – Vulnerable 

Wimmer’s Shrew – previously Critically Endangered – has been moved to Vulnerable status since new records have expanded the known distribution of this species. Found in Côte d’Ivoire and now also recorded in Ghana, this species is still under threat from land use change for agriculture, urbanisation, logging, and mining operations (both legal and illegal). The assessment highlights that research is needed to determine its trends, improve knowledge of its ecology, and measure the impact of threats. 

Photo credit: Dr. Jan Decher. Male and female from pitfall trap in Atewa, Ghana. 

Northern Chinese Flying Squirrel (Aeretes melanopterus) – Least Concern 

This species is endemic to mountainous forests in China between 1,200 and 3,000m above sea level. In the latest update it has been moved from Near Threatened to Least Concern, because there is no evidence that it is facing any severe threats and is considered to have a stable population. Whilst it does have a very large extent of occurrence (EOO), it is thought that it has a relatively low population size. Assessors highlighted that taxonomic research is needed to determine whether the two sub-species are distinct enough to be considered separate species. 

Image from G. Masson, 1868-1874, Recherches pour servir à l’histoire naturelle des mammifères.

Kenneth’s White-toothed Rat (Berylmys mackenziei) – Least Concern and Manipur White-toothed Rat (Berylmys manipulus) –  Least Concern 

In this update we also submitted two Berylmys species, moving them from Data Deficient to Least Concern. Both of these burrowing rodents appear to be widespread across parts of Asia, but likely face threats of habitat loss and possibly even hunting. Berylmys mackenziei  in particular remains under some taxonomic uncertainty, so further research is needed. 

Photo credit: from Dhananjoy, Ch., Ibemhal, A., Brajendra, N., Laishram, J.M. and Singh, C.B. (2011) Biodiversity of rat species in Manipur. NeBIO 2, 23-26. In image, top: B. mackenziei and bottom: B. manipulus.

The Iberian Desman

Desmans are semi-aquatic small mammals that are members of the Talpidae mole family. The Iberian Desman (Galemys pyrenaicus) is endemic to the Iberian Peninsula, where it is restricted to Andorra, France, northern and central Spain, and northern Portugal.

The species is extremely well adapted to a semiaquatic lifestyle, where it mainly lives in fast-flowing mountain streams. The species favours watercourses where the margins offer some shelter, and it requires clean and well oxygenated water, mostly due to the requirements of its main prey, aquatic macroinvertebrates. It is therefore a good indicator species for healthy river systems.

It is listed as Endangered on the IUCN Red List of Threatened Species, due to large declines in its range and populations. The main threat factors identified are the fragmentation and isolation of populations due to the construction of large dams and hydroelectric dams, water pollution, as well as the alteration of riverbanks and natural riparian vegetation. The disappearance of local populations may be due to predation by invasive non-native species such as the American mink (Neogale vison) and the recent range expansion of otters.

Setting the scene for a trans-national action plan 

In November 2023 in Andorra La Vella, a meeting was held to start the process of conservation planning, including by identifying major threats and summarising the evidence behind the declines. In the meeting we came up with a list of all the stakeholders that should be involved in the conservation of the species.

The event was organized by the IUCN Centre for Mediterranean Cooperation (IUCN Med). IUCN Med, as part of its species conservation initiatives in the Mediterranean region, is working on this initiative after receiving a request from some interested parties to lead actions at a trans-national level. This is due to the importance of the cross-border approach in the protection of the remaining populations.

Desman trans-boundary action planning workshop 

In January 2025, more than 40 Iberian Desman experts from Andorra, Spain, France and Portugal met with other interested stakeholders to develop a trans-national conservation plan and define the urgent measures to prevent the extinction of this unique freshwater species.

Iberian Desman workshop group photo 2025

The workshop was held in Madrid and organised by IUCN Med with the support of MITECO. The workshop was facilitated by the IUCN Species Survival Commission’s (SSC) Conservation Planning Specialist Group (CPSG).

Iberian Desman workshop about to kick-off!

Outcomes included: 

• The development of a trans-boundary strategic vision to guide conservation actions for the species.  

• A detailed prioritisation and zoning analysis of specific threats was carried out for each identified population cluster.  

• A fundamental part of the process was to set clear objectives, concrete actions and define the key actors involved in the implementation of the trans-boundary strategy.  

• A multidisciplinary committee was formed to facilitate the coordination and monitoring of conservation activities across countries. Their main role will be the prioritisation, promotion and coordination of conservation actions for the species throughout its range. 

Iberian Desman workshop day 1

The potential role for ex-site measures in the action plan 

Within the workshop, a separate group was set up to talk through the potential roles for ex-situ conservation. This is certainly a challenging species for ex-situ actions because, whilst it has been kept well, it has never been successfully bred in captivity.

The group included representatives from ADEFFA (the only facility where the species is currently kept in captivity), the EAZA Small Mammal TAG, Ros Kennerley representing the SMSG, and other interested parties from each range-country.

We agreed that within-range facilities and a serious investment of resources are required to establish a successful breeding programme at a sufficient scale to provide enough animals for population reinforcement and possibly reintroduction. Further details of requirements and a funding plan will be drafted in the coming months.

One of the break-out groups, considering the potential role for ex-situ conservation efforts

Richard Viduna (EAZA Small Mammal TAG chair), Ros Kennerley (SMSG Co-Chair), and Dijana Beneta (Vice-Chair, EAZA Small Mammal TAG)

Next steps

The finalised conservation action plan will be approved and published later this year. Stay tuned! 

Alpenzoo and the IUCN SSC Small Mammal Specialist Group (SMSG) – who have collaborated to create a Centre for Species Survival – are pleased to welcome Nora Weyer to the team. Nora is based at Alpenzoo in Austria and will be working closely with the SMSG on lots of small mammal Red List work. Hear more from Nora below.

“I am a passionate conservation biologist with over a decade of experience in wildlife research, conservation planning, and international collaboration. I hold a Ph.D. in Biology, specializing in the ecophysiology of large and small mammals, with extensive fieldwork in southern Africa.

As the Conservation Officer at Alpenzoo Innsbruck, I coordinate the 19th IUCN Centre for Species Survival and lead conservation programs focused on small mammals worldwide and alpine species in the region, including the Bavarian pine vole. I work closely with the IUCN SSC Small Mammal Specialist Group, the Conservation Planning Specialist Group (CPSG), governments, and NGOs to drive impactful conservation initiatives.

Before joining Alpenzoo, I worked with the Convention on the Conservation of Migratory Species of Wild Animals (CMS) and the Intergovernmental Panel on Climate Change (IPCC). My background in wildlife conservation physiology includes extensive research on wild animal species in southern Africa. For my Ph.D., I studied the impacts of climate change on free-living aardvarks in the Kalahari semi-desert, while my M.Sc. research focused on torpor patterns in the African woodland dormouse. I have also contributed to research on other wild species, including marine turtles and pangolins.

In addition to my role with the IUCN SSC Small Mammal Specialist Group, I am an active member of the IUCN SSC Afrotheria Specialist Group.

I have played a key role in species conservation action plans and assessments, international policy frameworks, and ecological research. I am dedicated to bridging science, policy, and conservation practice, contributing to species survival through evidence-based strategies and collaboration.”

Last autumn, we — a group of Middlebury College students working with IUCN SMSG deputy chair Dr. Alexis Mychajliw— had the wonderful opportunity to attend BeaverCon in Boulder, CO. BeaverCon is a biennial conference hosted by the Beaver Institute that promotes beaver conservation, restoration ecology, and community engagement. With funding from Middlebury College and the Conservation Paleobiology Network, six of us students were able to attend all three days of the conference.

North American beavers (Castor canadensis) once inhabited wetlands across the entirety of North America. They are keystone critters that provide essential benefits to ecosystems by building their dams and lodges. By blocking up streams, beavers create new wetland habitat to support additional wildlife and store water in the water table. This can build resilience in ecosystems against wildfires and droughts. However, beavers are also considered a nuisance for many communities by interfering with manmade infrastructure, and many states lack comprehensive human-beaver coexistence management programs. Beavers are currently listed as Least Concern on the IUCN Red List because of their wide range, yet little is known about just how ecologically functional they are relative to pre-Fur Trade population sizes and distributions. As a result, researchers are now investigating beavers through time as part of an NSF grant (DISES 2109168) and conducting the first IUCN Green Status assessment for this species, which will better take into account historical baselines.

Welcome to BeaverCon! BeaverCon had a bring-your-own-shirt system that encouraged people to reuse shirts for on-site screenprinting their logo. Photos by Alexis Mychajliw.

At BeaverCon, we had the opportunity to attend dozens of informative talks on a wide range of subjects. We learned about the role of beavers in fire ecology, GIS tools that identify beaver wetlands, human-beaver coexistence projects in urban areas, and more. We had the opportunity to converse with scientists, community leaders, ranchers, policy analysts, and artists from across the country that were passionate about beavers. We even had the privilege of hearing Jared Polis, the governor of Colorado, talk about his efforts to protect beavers and the ecosystems they support!

We were able to add to this conversation and practice our data synthesis and presentation skills to a general audience. We presented a project we completed this spring in Dr. Alexis Mychajliw’s Conservation Biology class of an ArcGIS StoryMap about the conservation of beavers in the southeast. We took data from a variety of open databases to create interactive media, crafting a story about the history and challenges that arise with human-beaver cohabitation in the southeast, as well as the benefits that beaver conservation provides to disadvantaged communities. We then adapted this presentation for BeaverCon to show audience members the applicability of ArcGIS StoryMaps for their organization, as it can be a key tool for science communication and education outreach.

Left: Middlebury College students (left to right: Lucy Day, Haydn Suske-Funk, Kendall Schilling, Helen Vaughn, Claire Ellerbrook, Samuel Medina) at BeaverCon, hosted at the University of Colorado, Boulder in October 2024. Right: the students being interviewed about their experience at BeaverCon for national television. Photos by Alexis Mychajliw.

We are incredibly grateful for the opportunity to have attended BeaverCon 2024. We gained experience in presenting, acquired a breathtaking array of beaver knowledge, and made important connections in the environmental field. Thank you to all our supporters who allowed us to develop foundational skills for conservation scientists!

Authors: Haydn Suske-Funk and Helen Vaughan

See the students’ TV appearance here!

SSC Leaders’ Meeting 2024
Photo credit @Environment Agency – Abu Dhabi (EAD)

Co-chairs Dr Ros Kennerley (based at Durrell) and Dr Tom Lacher (Texas A&M University) attended the 5th IUCN Species Survival Commission (SSC) Leaders’ Meeting in Abu Dhabi. This event brought together more than 300 conservation leaders to address the urgently needed interconnected solutions to protect biodiversity, stabilise climate, and support human well-being.

Together, we drafted an SSC declaration “Saving Species Sustains Life“.

We are thrilled that the SMSG was amongst a few specialist groups that won an ‘Excellence Award’ for our work from 2021-2023.

Dr Jon Paul Rodríguez (Chair of the SSC) presenting the Excellence Award to the SMSG co-chairs

SMSG presentation

Dr Tom Lacher presenting at the SSC Leaders’ Meeting
Photo credit @Environment Agency – Abu Dhabi (EAD)

Tom gave a talk about the SMSG’s achievements within the Assess part of the SSC Assess-Plan-Act cycle. The presentation highlighted work such as our Sulawesi workshop held last year, the Green Status of Species assessments we have produced, and the large European Pulse Project that we contributed to. The pulse project reassessed all mammals in the European region.

New CSS for small mammals

It was great to meet Dr André Stadler, who is the SMSG’s Ex-situ Focal Point and the director of AlpenZoo, Austria, who recently set up a Centre for Species Survival (CSS) to support small mammal conservation. The recruitment process is underway, and we hope to have a Project Officer in post in very early 2025.

Dr André Stadler and Dr Kira Mileham at the SSC Leaders’ Meeting

Dr Ros Kennerley with the SMSG poster at the SSC Leaders’ Meeting

We also had an opportunity to show off some of our projects and successes of our members across the world by having a poster displayed at the event.

The four-day meeting was intense, with lots of plenaries, workshops and networking opportunities.

Amongst the many delegates was Dr Barney Long, Senior Director of Conservation Strategies at re:wild. We have just heard that Re:wild will continue to provide support to the SMSG for 2025, making it the 9^th year that they have championed the SMSG!

The meeting came to a wonderful finale thanks to The Mohamed bin Zayed Species Conservation Fund who hosted a fantastic dinner for us all.

The IUCN Red List of Threatened Species has just published its second update of the year (28th October 2024), including reassessments for hundreds of small mammal species submitted by the Small Mammal Specialist Group (SMSG). Unfortunately, the most significant changes concern a worsening in Red List categories. Read more about some of these assessments below. 

Admiralty Rat (Rattus detentus) – Critically Endangered (Possibly Extinct)

Formally described only as recently as 2016 from Manus Island of Papua New Guinea, this species has only ever been recorded a handful of times. Unfortunately, hope for this species is slim, as multiple surveys undertaken between 1962 and 2014 have failed to record it. Local hunters in 2014 considered it too rare to be worth hunting, and targeted surveys and ethnographic questionnaires since then have failed to find evidence of the species. It is possible that is has already disappeared.

Applying the IUCN’s recommended extinction assessment framework, we estimated the probability that the species is extinct to be 0.76. The Admiralty Rat now joins the 15 other rodent species that are already listed as Possibly Extinct.

Bahaman Hutia (Geocapromys ingrahami) – Critically Endangered

Populations of this hutia have already been extirpated from parts of the Bahamas due to a hunting, predation by dogs and possibly cats, and competition with other invasive mammals. This species is now only thought to occur on three cays, though persistence on one of these is uncertain.

Since this species has such a small, restricted distribution, it is only found in a few locations, and there is ongoing decline, it has reached the status of Critically Endangered. A Species Action Plan which considers future reintroduction options is urgently needed.

Heath Mouse (Pseudomys shortridgei) – Endangered 

The Heath Mouse is found in parts of South and Western Australia, where lack of success in targeted surveying has raised cause for concern. It’s thought that climate change, wildfires, habitat loss and degradation, as well as predation by cats and foxes, have been driving a decline in numbers. Now, based on its small area of occupancy, low number of locations, and continuing decline, this species is Endangered.

Seram Orange Melomys (Melomys fulgens) – Vulnerable 

This species – previously unrecorded since 1920 and assessed as Data Deficient – was recently documented as surviving on the island of Seram in Indonesia, in research led by SMSG Deputy Chair for Conservation Actions, Prof. Sam Turvey.

Whilst this “rediscovery” is incredibly promising for the species, its recent Red List assessment highlights that we must take action to continue survey work. It has been listed as Vulnerable based on its small distribution and threats to its lowland forest habitat (logging and agriculture).

Western European Hedgehog (Erinaceus europaeus) – Near Threatened

A well-recognised and widely-loved small mammal, the Western European Hedgehog is nowadays facing a multitude of threats. Roads, agricultural intensification and urban growth have likely affected populations across its range. With evidence indicating local and national declines thar are approaching, and in some areas, exceeding 30% over a decade, this hedgehog has been moved from the category of Least Concern to Near Threatened.