The Scandentia are a small order of mammals once grouped with the Insectivora. Their common name is tree-shrew but they are not really shrews and many of them do not live in trees. The scandentid tree-shrews were found to be so different enough from true shrews and other Insectivores that they were separated in 1984 into their own order. There are nineteen described species of tree-shrews, all in the same family Tupaiidae, and they are found in the deciduous forests of central and Southeast Asia. Ten of the species are found only in Borneo. Some investigators have suggested that they may be closely related to primates and may represent an evolutionary offshoot from the group that evolved from insectivores into the primitive primates. However the best argument against including the scandentids in the primates is that tree-shrews share no characteristics with the primates that are found in no other group.
Tree-shrews have pointed noses and shrew-like faces, long weasel-like bodies and most have squirrel-like, bushy tails. Some are ground dwellers but most live a semi-arboreal life in trees, although their limbs are not prehensile. The longer snouted varieties tend to live on the ground where their snouts are used to root around in the leaf litter for food items. They are omnivorous, eating a variety of insects and other arthropods along with fruits and other vegetable matter, earthworms and even the occasional fish, frog or small mammal. They are mostly active in daytime although the most primitive species, the pen-tailed tree-shrew is nocturnal. This species also has a naked, more rat-like tail. All tree-shrews have large eyes and excellent hearing. Their behaviour is so much like squirrels that the Malays call them squirrels and in American pet shops. They are often sold as “Asian squirrels”. However they do not have the long whiskers of squirrels and in fact are not closely related to squirrels at all.
Some species are solitary while others are more social and live in small groups. In general they pair off into monogamous relationships. Males are usually highly territorial and mark their territories with musk glands. Nests are built in tree hollows lined with leaves. Gestation is about fifty days and litters are usually one to three babies that are born hairless and helpless. The babies are left alone for long periods so they huddle together for warmth and drink copious quantities of milk when their mother returns from long foraging trips. Their life span is usually about two to three years and their main predators are snakes, small mammalian carnivores and birds of prey. However the greatest threat to tree-shrews is habitat destruction and the clearing of their forests. The majority of tree-shrews are still common but a few are now listed as vulnerable or threatened.
References
http://animaldiversity.ummz.umich.edu/site/accounts/information/Scandentia.html
http://www.americazoo.com/goto/index/mammals/scandentia.htm
http://thewebsiteofeverything.com/animals/mammals/Scandentia/
http://www.theprimata.com/tree_shrews.html
http://animals.jrank.org/pages/2802/Tree-Shrews-Scandentia.html
