Tree shrews might well be one of the most fascinating creatures you’ve never heard of!
These small mammals – who, despite resembling squirrels and “‘true’ shrews”, are neither rodents nor true shrews – are most closely related to primates! In fact, tree shrews used to be included in the order Primates and were “classified as ‘primitive prosimian’ before being moved into their own cade”. Still, molecular phylogenetic studies suggest that these mammals “should be given the same rank (order) as primates”.
The 23 species of tree shrews are the “only members of the order Scandentia”, named from the Latin word “scandere”, which means “to climb”. This order is made up of two families, which scientists believe “separated 60 million years ago”: (1) the Tupaiidae, which includes 22 species, and (2) the Ptilocercidae, which includes only one species (the pen-tailed treeshrew).
You should also know that these fascinating creatures, who have “large eyes, conspicuous ears”, “long muzzle[s]”, and “greyish to reddish-brown fur”:
- Count their “[b]rains” and “agility” among their “[s]uper powers”!
- Have the “highest brain-to-mass ratio among all mammals”, including humans!
- Enjoy “acute senses of hearing and smell, along with good vision” and good memories!
- Are the only mammals – other than humans! – who seek out spicy foods! A single genetic mutation reduces their pain response to capsaicinoids, and this mutation is believed to represent an “evolutionary adaptation to be able to consume spicy foods in their natural habitats”.
- Count fruit among their favorite foods! Their “small body size, high heart rate, and short digestive tract” result in a “high metabolic rate” that requires them “to eat frequently”, and they “can spend as many as 11 hours per day foraging” for food.
- Are diurnal, with the exception of the pen-tailed tree shrew, who is nocturnal!
- Are native to the tropical forests of South and Southeast Asia!
- Are either “terrestrial, scurrying rapidly over the forest floor . . . and rarely climbing trees” or “arboreal but occasionally go to the ground.” They “nest in tree cavities and on the ground, using hollow tree trunks, rock crevices, and ground cavities.”
- Live in “small family groups” within defined territories! Tree shrews mark their territories with “urine or secretions from scent glands” and “actively defend them from intruders”.
- “[S]hare an unusual nutritional relationship with pitcher-plants”: tree shrews feed on the plants’ “‘nectar’ produced by glands on the inner surface of the plant[s’] lid and in return almost immediately defecate into the pitcher, supplying the plant with a nitrogen fix.”
- They are threatened by habitat loss (resulting from farming, ranching, and logging), as well as hunting and trapping.