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Today on Animal Fact Files we’re discussing tree shrews. Although their common name is tree shrew, they aren't actually shrews. They may also look like squirrels, but tree shrews aren’t even rodents. Genetically speaking, tree shrews are closer to humans than squirrels on the tree of life! These small mammals live throughout Southeast Asia, inhabiting forested regions. Their common name implies that they spend a lot of their time in trees, however tree shrews are not strictly arboreal. They’ll scurry along the ground through the damp leaf litter in search of food.

Something noteworthy about tree shrews is that they are some of the only known mammals to voluntarily eat spicy meals. In fact, humans are just about the only other species that do this! It’s believed tree shrews have developed the ability to eat capsaicin-rich food over time in order to increase their potential food. If no other nearby mammals are eating anything spicy, then the tree shrews have less competition for this resource! Other meals for these squirrel-like creatures include insects, such as beetles, as well as fruit. Tree shrews also eat the nectar of pitcher plants. This is a mutual relationship. The tree shrew gets nutrients from the plant’s tasty nectar, and the plant gets nutrients from the tree shrew’s poop! Before leaving, the generous tree shrew leaves a little present behind in the pitcher plant’s cup which will feed the plant over time.

Tree shrews are the only living members of their Order and there are about 20 described species, although, as always, more research will lead to changes in this number. They’re about squirrel-sized, ranging in body length from 5 to 10 inches (12-25 cm). Their tail is typically the same length as their body. Tree shrews weigh just over half a pound (230 g) at their largest, although in some species the adults barely reach the weight of a golf ball! These mammals are gray, brown, tan, or even olive toned with a lighter underside and bare ears. No really, they’re hairless. It’s like someone took some human ears, shrunk them down, and glued them to the sides of a tree shrew’s head.

Mammals are pretty well known for their parental investment in their offspring. Tree shrews, however, didn’t get the memo. After a 50 day gestation, mother tree shrews give birth to 2 to 4 young in a nest that she specifically builds separate from her own nest. The babies are hairless and helpless, but they only get attention from Mom every couple of days when she shows up to nurse them. Outside of this, she essentially ignores them. No snuggling like polar bears, grooming like cats, or cleaning out the nest like rabbits– tree shrew mothers leave their babies to defend themselves, and won’t even intervene when they’re under duress! This is similar to a deer mother who gives birth and only visits her offspring periodically so the babies are less conspicuous to predators such as wild cats and birds of prey. Young tree shrews stay in their parent’s territory for about four months until they reach reproductive maturity. In the wild, these animals typically only live to be about 2 years old, but they can live for more than a decade in captivity!

Tree shrews are important animals in scientific research. Their close relationship to primates makes them helpful for determining how certain factors may affect humans. Since the 1960s, these quick breeding, small mammals have been used in studies to help broaden our understanding of cancer, depression, liver disease, and more! Plus, tree shrews have some of the largest brains in the animal kingdom in relation to body size– when scaled up for body mass, a tree shrew’s brain is even larger than a human’s!

For more facts on tree shrews, check out the links below. Give a thumbs up if you learned something new today. Thank you to our Patrons SpikeSpiegel93, Dad, and everyone else for their support of this channel! And thank you for watching Animal Fact Files!