Distinct from Asioryctes, the skull of Tupaia was shorter and lacks incisors 1, 2 and 5. The canine is reduced to the size and shape of a premolar. Premolar #2 is absent. The orbit is larger and each eyeball is protected by a ring of bone. The tiny ear bones are protected by the bulla.
The cervicals are shorter. The dorsal ribs were more gracile. The lumbar region was more fully developed with enlarged transverse processes. The caudals are more gracile.
The scapula is broader and provided with a central ridge or spine.
The ilium has a broader anterior process. The tibia is more robust than the fibula.
A pair of feathery extra tongues are found beneath the main tongue. These are also found in lemurs.
Pouncing on prey while perched on a tree branch requires greater skills and a larger brain. To find prey tree shrews rely on their eyes and their hands. Tree shrews gallop, which is basically a series of leaps in which all four feet are in the air at the same time. That's a new way to locomote.
Tree shrews are active during daylight, which sets them apart from more primitive animals. Because of this their internal temperatures are set higher, closer to the 98.6 degrees. To maintain their temperature and their active lifestyle a tree shrew must eat its weight in food each day.
Tree shrews produce a few sounds, from a snarling hiss to a piercing squeal. They also chatter when alarmed. Most have cartilage that shapes the outer ear. Like a dog, tree shrews can draw back their upper lip to expose their teeth, which is their only facial expression.
Males and females are almost identical. Females give birth to between one and three young after 50-day pregnancy. Babies are born naked with ears and eyes closed. Species that give birth to a single baby have a single pair of breasts. Those that give birth to three at a time have three pairs of breasts. Newborns are nestbound. They receive maternal visits every other day for no more than 10 minutes at a time. After 6 weeks they are weaned. They mature in 4 months.