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Searching for mammals in the mountains of New Guinea

The New Guinea region is known for being one of the most species-rich places in the world. Located north of Australia and south-east of Asia, New Guinea’s topographical complexity and geographic isolation has given rise to a huge diversity of life, much of it endemic.

The island is home to at least 40 small mammal species found nowhere else on earth. However, small mammals in this region are not extensively monitored and we know little about their ranges, population statuses and threats.

The expeditions

Daniel Solomon Okena, who has recently joined the SMSG, is a Papua New Guinean researcher affiliated with the University of South Bohemia (Czech Republic). Daniel’s PhD project aims to improve knowledge of the island’s mammal life by surveying non-volant mammal communities along an elevational gradient in Huon Peninsula, north-eastern Papua New Guinea.

Daniel has already sampled a range of sites up to an incredible 3,700 m in elevation. Working in a range of habitats including dense lowland forest, montane cloud forest and alpine grasslands, Daniel and his team use survey methods such as Elliott and pitfall trapping, as well as interviews with local hunters. Sometimes, hunters are willing to share skulls and other objects with the team which help to build an understanding of where certain species are found.

Although conducting research in these remote mountain sites comes with the obvious challenges of accessing steep and dangerous bush tracks, Daniel is undeterred. He says:

“Just being out there in the field camp is so amazing. You get to enjoy nature. But when you start to see mammals up close from traps and hunters, the adrenaline reaches another level.”

The findings

So far, the study has documented a range of rodents, marsupials and a monotreme (possibly the first Eastern Long-beaked Echidna Zaglossus bartoni ever recorded via pitfall trapping). Daniel’s rodent results include a number of endemic species such as Shaw Mayer’s Shrew Mouse Pseudohydromys ellermani (Least Concern), the Greater Small-toothed Rat Macruromys major (Least Concern) and Southern Groove-toothed Moss Mouse Microhydromys argenteus (Data Deficient). Gathering new records of Data Deficient rodents such as the latter will be particularly useful when updating their Red List assessments, giving us a better idea of the distributional spread and potential conservation statuses of little-studied taxa.

The next stage of the PhD focuses on increased pitfall trapping to detect species that other methods might fail to find. In addition, Daniel continues to work on identifying any specimens collected. This includes specimens that might look quite similar but are completely different taxa – a common issue when it comes to certain rodent groups! Daniel will make use of genetic sequencing to tackle this. We look forward to hearing more about what these analyses reveal.

Daniel Solomon Okena’s PhD is supported by the Biology Center of the Czech Academy of Science (in collaboration with the New Guinea Binatang Center), the University of South Bohemia and Charles University (in collaboration with the Institute of Vertebrate Biology of the Czech Academy Science).

Author: Abi Gazzard (SMSG Programme Officer)

International Hedgehog Conference

Erinaceus europaeus

On the 13th-14th January 2024, over 200 wildlife rehabilitators, researchers and conservation practitioners gathered at Hartpury University (UK) for the International Conference for Hedgehog Rehabilitators. The meeting presented the perfect opportunity for strengthening collaboration between hedgehog scientists and carers around the world! 

A variety of topics were covered during the two-day conference. Attendees had the chance to hear from UK NGOs about hedgehog conservation plans, from vets presenting talks on medical treatment and intervention, and from researchers discussing projects on pesticides, diet and wildlife rescue. Co-organisers Dr Lucy Bearman-Brown and Dr Sophie Lund Rasmussen hosted workshops on the development of an international hedgehog records database as well as research priorities.  

Whilst most of the attendees’ work focuses on the West European Hedgehog (Erinaceus europaeus), there was also talk of other Erinaceids including the Northern White-breasted Hedgehog (Erinaceus roumanicus), which is found in contact zones with E. europaeus. Dr Barbora Bolfíková has been studying the genetics of hedgehogs in these overlapping areas of distribution. The SMSG’s Programme Officer, Dr Abi Gazzard, spoke about two additional species, the Long-eared (Hemiechinus auritus) and North African Hedgehog (Atelerix algirus), in the presentation “Assessing the Statuses of Hedgehogs in Europe”, giving an overview Red Listing and where the obvious data gaps occur. We also heard about a hedgehog from southern India: SMSG member Dr Brawin Kumar introduced us to his Madras Hedgehog (Paraechinus nudiventris) project. Brawin’s work has done an excellent job of raising the profile of this little-known species. Through school sessions, traditional puppet shows, comic books, and questionnaire surveys, Brawin has engaged with local communities across the Tamil Nadu region. 

Rounding off the conference, the attendees heard about hedgehogs from a different angle – as pests. In Uist, Scotland, the Royal Society for the Protection of Birds (RSPB) is developing a project to conserve ground-nesting birds threatened by introduced West European Hedgehogs, though their plans consider the challenges faced by hedgehogs in their native range.  

It was brilliant to attend a conference with such an open-minded audience from a wide range of disciplines, though one common goal is clear – ensuring the preservation of these prickly, popular small mammals. 

Many thanks to the event’s organisers, supporters, speakers and attendees, and to Hartpury University for hosting us.

Below: Abi Gazzard and Brawin Kumar at the conference, and Brawin presenting on the Madras Hedgehog.

Author: Abi Gazzard (SMSG Programme Officer)

New study: why are some species rediscovered while others remain lost?

One third of remaining lost mammal species are restricted to small areas, such as islands, where they are particularly vulnerable to extinction. The Bramble Cay Melomys (Melomys rubicola) was once considered to be a lost species, but has now been declared extinct. Source: State of Queensland/Wikimedia.

Lost species are those that have been lost to science for at least a decade. Many small mammals haven’t been surveyed since their initial discovery over 100 years ago, remaining unrecorded today. Some potentially go extinct before we have a chance to find them, whilst others are thankfully ‘rediscovered’ through targeted campaigns and fieldwork. Such rediscovered species tend to have restricted ranges and remain highly threatened. Thus, rediscoveries have important conservation implications.

But why is it that some species are rediscovered and others aren’t?

New research, led by Thomas Evans (Freie Universität Berlin) with co-authors including the SMSG’s Co-Chairs, Thomas Lacher Jr and Rosalind Kennerley, has attempted to understand why certain tetrapod species are rediscovered but others not.

Creating a database of lost and rediscovered tetrapods, the researchers examined patterns in distribution and factors influencing rediscovery, such as body mass, habitat requirements and influence of human activities.

What does this mean for small mammals?

Nearly half (49%) of lost mammal species are rodents, and the research suggests that there are more lost and fewer rediscovered rodents than would be expected by chance.

Lost rodents, like other small taxa, might be perceived to be uncharismatic and are thus neglected in terms of conservation effort. They may also be hard to find – some are nocturnal or occupy habitats that are difficult for researchers to access. Whatever the reason, we need to find ways to improve efforts of searching for these neglected lost species, before it’s too late.

Read more in The Conversation article here, and find the full paper linked below:

Lindken, T. et al. (2024) What factors influence the rediscovery of lost tetrapod species? Global Change Biology 30, 1,

Author: Abi Gazzard (SMSG Programme Officer)

SMSG member joins renowned Durrell Wildlife Conservation Trust training programme

The 12-week Durrell Endangered Species Management Graduate Certificate (DESMAN) course is Durrell’s flagship training programme. Open to early-career conservationists, or graduate- or postgraduate-level conservationists working towards employment in the sector, DESMAN equips participants with a broad range of practical skills, knowledge and connections.

Earlier this year, the SMSG supported one of our members – Rifa Nanziba – with her application to the DESMAN course. Rifa had not-long completed her MSc degree in Environment Management during which she focused on human-squirrel conflict in rural areas of Naogaon, Bangladesh. We were thrilled when Rifa’s DESMAN application was successful and, even further, when she was granted a full scholarship to the course. From September-December, she stayed at the Durrell Conservation Academy in Jersey (Channel Islands) for her studies. Here’s what Rifa has to say about it: 

“Attending the DESMAN course at the Durrell Conservation Academy, validated by the University of Kent, was a life-changing experience for me. It opened new doors and felt like a dream come true. I am grateful for the support and recommendations from IUCN SSC SMSG Co-chair Dr Ros Kennerley, Programme Officer Dr Abi Gazzard, and my mentor, Muntasir Akash. 

I found myself drawn to the teachings of DESMAN, a course crafted to set up conservationists with a diverse array of skills, enabling them to achieve peak efficacy in managing and participating in conservation projects. Under the tutelage of the renowned scientist Carl Jones, I was initiated into the intricacies of Species and Population Management. The course imparted valuable knowledge in statistics, IUCN Red List assessments, GIS, project planning and management, research methods, and survey techniques such as camera trapping, radio telemetry, and the use of drones. Additionally, we explored topics such as human-wildlife conflict, community conservation and livelihoods, budgeting, and grant proposal writing. I had an amazing chance to meet Lee Durrell and hear about her and Gerald Durrell’s incredible conservation work and projects around the world, along with how the famous Jersey Zoo and Durrell Wildlife Conservation Trust were established.

What set DESMAN apart was the emphasis on practical work, complementing the theoretical lectures. As part of this, I was privileged to shadow mammal keepers for four days in Jersey Zoo, honing my mammal husbandry skills, helping me to realise that I might want to be a wildlife rehabilitator too as in my country there are not many rehabilitation centres. Furthermore, I had the opportunity to connect with a vast network of wildlife enthusiasts through Durrell, who remain eager to support me in my future endeavours. Besides all the study and technical experience, I had a blast in Jersey as the local volunteers were kind enough to take us to many beautiful and historical places on the island. As well as that, I gained a group of fellow DESMAN participants as my friends who, after staying with each other for a whole 3 months, are without any doubt also part of my knowledge, experience and networking.

After completing the DESMAN course, I feel confident in my ability to work in wildlife conservation, specifically with small mammals in Bangladesh. I am excited to apply my new knowledge and skills in this field.” 

Rifa’s final assessment was a hypothetical project proposal. She chose to write a proposal to questionnaire-survey the Santal community of Naogaon on the drivers and impacts of small mammal hunting and consumption – very little is currently known about the use of small mammals in this region. We look forward to seeing what Rifa gets up to next! 

If you are a small mammal researcher interested in furthering your skills through Durrell’s DESMAN course, or may know of suitable participants, please get in touch. Places are limited. You can find more information about the syllabus here and scholarships here. 

By Rifa Nanziba and Abi Gazzard

My internship experience: Thi Nguyen

Summer intern Thi

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.

Studying Wolffsohn’s Viscacha

Imagine a feathery-tailed, round rabbit-like creature munching on grasses in the mountains of Patagonia. This is Wolffsohn’s Viscacha Lagidium wolffsohni, and despite possessing long, 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 the Sierra 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! 

If you’d like to learn more about the project and Programa Patagonia’s work in general, check out their Instagram page here: 

Sulawesi Small Mammal Workshop

Sulawesi is 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 originsthere’s nowhere else quite like it.

Why Sulawesi?

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, the SMSG set out to address some of these gaps by hosting the Sulawesi Small Mammal Workshop.  

The workshop

The workshop took place in Bogor, Java, and was funded kindly by an IUCN SSC Internal Grant and through the SMSG’s core funder Re:wild. Small mammal specialists and conservationists travelled from Sulawesi (Tadulako University, Universitas Sulawesi Barat, University of Sam Ratulangi, and PROGRES), Java (Museum Zoologicum Bogoriense) and Australia (Museums Victoria). Collectively, the participants offered a wealth of knowledge on small mammals, records, taxonomy and threats, as well as Sulawesi’s geography, habitats, communities and cultures. 

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.

  1. Long-tailed Sulawesian Shrew Rat (Tateomys macrocercus)
  2. Sulawesi White-handed Shrew (Crocidura rhoditis)
  3. Sommer’s Sulawesi Rat (Sommeromys macrorhinos)

In defence of rodents – why healthy ecosystems need them

The following article is authored by Ros Kennerley (SMSG Co-Chair), Abi Gazzard (SMSG Programme Officer), and Connor Panter (PhD candidate), and has been republished from The Conversation under a Creative Commons license. 

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.

A small mouse on a bramble branch with blackberries.

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.

A beaver in water gnawing on a branch.

Even beavers can’t beat the anti-rodent bias. WildMedia/Shutterstock

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.The Conversation

Read the original article on The Conversation here.

Research and awareness programme to begin for the endangered Baer’s Wood Mouse

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. 

Author: Abi Gazzard (SMSG Programme Officer)

Baer’s Wood Mouse image: Wilson, D.E., Mittermeier, R.A. and Lacher, T.E. (2017): Muridae. In: Handbook of the Mammals of the World – Volume 7 Rodents II.

Santa Catarina’s Guinea Pig: the rarest rodent in the world?

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. 

Over time, characteristics of this species have been shaped by island conditions in a phenomenon termed “island syndrome”. Santa Catarina’s Guinea Pigs have high survival rates, small home ranges and slow reproductive processes relative to that of similar continental species. Consequently, their population is small in number; surveys undertaken in 2004-2005 suggested that the island was inhabited by less than 50 individuals which qualified the guinea pigs for Critically Endangered status on the IUCN Red List. The IUCN later cited them in a list of the 100 most threatened species on the planet 

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