[4][5] Raffles described the genus as having an elongated snout, eight to 10 incisors, well-developed limbs, five-toed naked feet, and the sole furnished with projecting pads and sharp claws, with a habit and tail of a squirrel.

[2] Marcus Ward Lyon published a revision of the genus in 1913, and also noted the squirrel-like appearance of Tupaia species, which only lack the long black whiskers and have smaller ears.

They do not have any markings on the face, the naked area of the nose is finely reticulated, an oblique stripe on the shoulder is more or less distinct, and the tail is haired but not tufted.

[9] The following species are in the genus Tupaia:[1] In the past, various authors proposed to place treeshrews in the ordinal rank Insectivora, or considered them close relatives of primates.

Since they are rarely seen crossing wide roads, populations likely are negatively affected by fragmentation of forests caused by logging operations.

[29] Common treeshrews observed in the Bukit Timah Nature Reserve defended diminishing food resources by chasing away residents of adjacent areas.

In contrast to primates, which produce one baby with longer gestation periods, treeshrews generally have litters of two or three young and are only in utero about 45 days.

[37] Since Tupaia species share so many similarities with primates, yet are more abundant and have more plentiful progeny than them, interest is increasing in using them as an alternative model for use in human medical research.

Successful psychosocial studies were carried out, and dramatic behavioral, neuroendocrinal, and physiological changes occurred in subordinate males of Tupaia, similar to depressed human patients.

[38] Tupaia species have been used to overcome the limitations of using rodent models in the study of human biology and disease mechanisms, as well as the development of new drugs and diagnostic tools.

This was advantageous because other possible candidates such as guinea pigs, rats, mice, and other rodents leave gaps in the information, especially regarding clinical symptoms and transmission.