Tufted Ground Squirrel Facts: Size, Teeth and Tail

Tufted Ground Squirrel Rheithrosciurus macrotis

Red list status: Vulnerable

Locations: Malaysia, Brunei, Indonesia (Borneo).

Appearance and behaviour

The tufted ground squirrel, or groove-toothed squirrel, is a striking nut-cracking rodent native to the island of Borneo. Weighing in at around 2 kg their bodies are overshadowed by a fluffy, charcoal-and-white frosted tail that’s 130% the volume of their body. Their head-and-body length is around 34 cm with a tail almost as long, bringing their total length to nearly 70 cm! They have the largest tail-to-body ratio of any animal on the planet.

Tufted ground squirrel teeth are saw-like for cracking nuts

Their sharp incisors feature 7-10 saw-like grooves that are perfect for cracking hard nuts. Their fur is primarily brown with a reddish tint, and they sport dramatic tufts of dark fur on their ears, giving them a striking appearance. They’re agile climbers and forage both on the forest floor and in the lower canopy.

Their “vampire squirrel” reputation is an urban myth

Although local folklore suggests that these squirrels attack deer from above to feast on their organs – there is no evidence! Researchers have yet to find scientific proof. Instead, these resilient ground-dwelling squirrels mostly munch on incredibly hard seeds, especially those from the Canarium tree.

Threats to the tufted ground squirrel

Palm oil deforestation: Conversion of their habitat into monoculture plantations like palm oil is a major threat.

Timber deforestation: Out of control logging practices impact their primary forest habitat.

Illegal hunting and trapping: Although not specifically targeted, these squirrels can become victims to poachers due to their ground-foraging habits.

You can help spread awareness about impacts of palm oil on these squirrels and 1000’s of other species. By using your wallet as a weapon every time you shop. Additionally, being a part of the #BoycottPalmOil #Boycott4Wildlife movement online will empower you to help them.

Habitat

Glimpsing Tufted Ground Squirrels in their natural home is exceedingly rate. They are found only on the island of Borneo and prefer dense lowland primary forests up to 1,100 meters in elevation. However, they will sometimes venture into secondary forests, orchards or smallholdings. They are elusive and not often seen, sometimes their fluffy tailed forms are captured by camera traps or chance sightings.

Diet

The tufted ground squirrel’s diet includes mostly hard seeds, particularly those of the Canarium tree. They also eat fruits, nuts, and insects, adapting to the available food sources in their forest habitat. Despite their sharp teeth, tales of their carnivorous nature have led to them being dubbed “vampire squirrels”, however these claims were subsequently discovered to be lacking in evidence. Their ultra sharp teeth give them the ability crack open even the toughest nuts.

Mating and reproduction

Much remains unknown about the mating and reproduction of the tufted ground squirrel due to their elusive nature. Researchers hope that future studies using motion-activated cameras will uncover more details about their behaviour, including how their elaborate tail might play a role in courtship.

Tufted ground squirrels facts

Why is Rheithrosciurus macrotis mistakenly known as the ‘vampire squirrel’?

Rheithrosciurus macrotis earned the sensational nickname “vampire squirrel” purely from local folklore and the virality of internet memes. Viral stories circulated across Borneo claiming that these rodents actively hunted large prey like deer by ripping out their throats. While it makes for a colourful story, it is a myth. Tufted ground squirrel teeth are sharp, yet are used only to crack hard nuts. The real story and many would say is far more shocking. The very lives of these squirrels is under threat from the endless growth of palm oil ecocide across Tufted ground squirrel range in Borneo.

Why is the Tufted ground squirrel tail so large?

The Tufted ground squirrel tail is an extreme physical adaptation that designed to foil attack from would-be predators. Their fluffy, charcoal-and-white frosted tail holds the largest tail-to-body volume ratio of any known mammal, measuring an incredible 130% the volume of their actual body. Researchers theorise this massive tail serves to confuse predators like clouded leopards during a chase by acting as a distracting decoy. Furthermore, when they forage on the forest floor, they curl this voluminous tail completely over their head to obscure their silhouette from aerial predators.

Are Tufted ground squirrels killing deer?

The story of the Tufted ground squirrel killing deer is a persistent local myth, not a scientific fact. According to Dayak folklore in Borneo, these squirrels drop from low branches onto unsuspecting muntjac deer, using their sharp teeth to sever the jugular vein and feast on the organs. However, scientists and camera traps have never recorded any evidence of this bloodthirsty behaviour. The “vampire squirrel” moniker is entirely legendary, arising likely from the squirrel’s bizarre, saw-like teeth and striking physical appearance.

What are Tufted ground squirrel teeth used for?

Tufted ground squirrel teeth are highly specialised tools for accessing vital plant nutrients, not weapons for hunting deer. Their large incisors feature 7 to 10 deep, longitudinal grooves that function exactly like a saw. Because their primary diet consists of incredibly hard seeds—particularly those from the Canarium tree, which defy even human hammering skills—they require these heavily ridged teeth to crack through the tough exterior shells. Consequently, their bizarre dentition is a masterpiece of evolutionary adaptation for a frugivorous diet in the rainforest.

What is the Tufted ground squirrel size and weight?

The Tufted ground squirrel is a remarkably large and heavily built rodent. Rheithrosciurus macrotis measures roughly 33 to 35 centimetres in head and body length, but their spectacular, voluminous tail adds another 30 to 34 centimetres, bringing their total length to almost 70 centimetres. Furthermore, mature adults typically weigh between 1 and 2 kilograms. This large body mass and extraordinary fluffy tail make them highly visible and entirely distinct from any other squirrel species found across Southeast Asia.

What is the Tufted ground squirrel location?

The Tufted ground squirrel location is restricted exclusively to the island of Borneo. They are an endemic species living in the primary rainforests of the Malaysian states of Sabah and Sarawak, the Indonesian province of Kalimantan, and the nation of Brunei. Rheithrosciurus macrotis absolutely requires dense, primary lowland and lower montane forests to survive, typically living at elevations below 1,100 metres. However, aggressive corporate palm oil deforestation is rapidly annihilating these specific locations across the entire island.

Support Tufted Ground Squirrel by going vegan and boycotting palm oil in the supermarket, it’s the #Boycott4Wildlife

Support the conservation of this species

This animal has no protections in place. Read about other forgotten species here. Create art to support this forgotten animal or raise awareness about them by sharing this post and using the #Boycottpalmoil #Boycott4Wildlife hashtags on social media. Also you can boycott palm oil in the supermarket.

Further Information

Meijaard, E. 2016. Rheithrosciurus macrotis. The IUCN Red List of Threatened Species 2016: e.T19474A22248783. https://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T19474A22248783.en. Accessed on 08 May 2024.

Pare, S. (2023, December 24). Tufted ground squirrel: The Borneo rodent once believed to disembowel deer and feast on their organs. https://www.livescience.com/animals/land-mammals/tufted-ground-squirrel-the-rodent-once-believed-to-disembowel-deer-and-feast-on-their-organs

Stokstad, E. (2015, September 2). ‘Vampire’ squirrel caught on film: Researchers in Borneo get first video of mammal with fluffiest tail. https://www.science.org/content/article/vampire-squirrel-caught-film-rev2

Wikipedia. (n.d.). Tufted ground squirrel. https://en.wikipedia.org/wiki/Tufted_ground_squirrel

---

---