Some investigators have suggested that they might also be related to Primates. Tree shrews are remarkably squirrel-like in external shape and size, and in fact I have seen them in pet stores being sold as Asian squirrels. Even the tail of most species is squirrel-like, long and heavily furred. They lack the long vibrissae of squirrels, however, and their forefeet are also rather different, having a full complement of 5 functional toes rather than 4, as in squirrels. The molars are broad and resemble many Insectivora in having a dilambodont cusp pattern.
Tree shrews are omnivorous.
Their eyes are large and their hearing is excellent. They are often active during the day. They may be found in trees or on the ground. Socially, some species are solitary, others are found in pairs or even small groups. Tree shrews are found in deciduous forests of central and southeastern Asia, but they do not occur on New Guinea or in Australia.