Pen-Tailed Tree Shrew (Ptilocercus lowii)


The Pen-Tailed Tree-Shrew (Ptilocercus lowii) is a species of tree shrew in the Ptilocercidae family. It is found in Indonesia, Malaysia, and Thailand. It is the only species in the genus Ptilocercus and the family Ptilocercidae. All other tree-shrews are in the family Tupaiidae.

The Pen-Tailed Tree-Shrew is the only known wild mammal that chronically (i.e., not just occasionally) consumes alcohol. A study of the Tree-Shrew in Malaysia found that it spends several hours consuming the equivalent of 10 to 12 glasses of wine with an alcohol content of up to 3.8% every night drinking naturally fermented nectar of the bertam palm. Despite consuming relatively large amounts of alcohol, the Pen-Tailed Tree-shrew does not become intoxicated. Measurements of a biomarker of ethanol breakdown suggest that they may be metabolizing it by a pathway that is not used as heavily by humans, a fellow member of the grand order of mammals Euarchonta. The species in Thailand is P.I continentus (Thomas1910)


Pen-Tailed Tree Shrews have a slender build and a long tail. They have well developed senses of hearing, smell and vision. The fur is short and velvety, dark greyish brown above and yellow grey below; the feet are brown, the toes whitish. There is a distinct white patch on either side of the muzzle and in some specimens the patch may almost be a stripe, extending more than halfway to the base of the ears. In contrast with other tree shrews, the ears are large and thin, standing away from the head; they are quite mobile, reflecting the greater reliance on hearing in a nocturnal animal. The whiskers are also more longer and rigid than in other tree shrews, and seem to be a more developed tactile organ. The eyes are larger and face more forward than in other Tree Shrews, and the retina of the eye is composed entirely of rods which is an adaptation for night vision. Locomotion on the ground is with a series of hops, with the tale inclined upwards and the tail almost vertical. In sleep the body is curled up in a ball with the tail curled around the body so that the feather of the tail covers the face. If they are disturbed they make a horse snarling hiss with the moth open, rather like the moon rat (Echinosorex). They are not at all shy


Pen-Tailed Tree Shrews can be found in the forests of Indonesia, Malaysia and Thailand. They are nocturnal and arboreal, inhabiting primary or secondary forest and rubber plantations, from sea level to 1000 meters. They usually seen in pairs, although as many as 5 have been seen in a single nest (Muul and Lim1971) . They sometimes nest in epiphytes in tall trees or in hollow branches 15 to 20 meters high, in a nest made of twigs, leaves and fibrous material and roughly lined with green leaves.


Pen-Tailed Tree Shrews are omnivores and they feed on a variety of insects, small vertebrates, fruit, nectar and seeds.

They are one of only seven wild animals that are known to consume alcohol. Each night they spend up to 2 hours drinking naturally fermented nectar from the bertam palm. Despite this consumption of alcohol, the Pen-Tailed Tree Shrew does not become intoxicated which suggests that the alcohol is metabolized in a different way than that used by humans.


After a gestation period of approximately 50 days, a litter of 3 - 4 young are born. At birth the young are blind and hairless, but they are able to leave the nest when they are a month old.

Tree Shrews reach sexual maturity at around 4 months old and they generally breed throughout the year with no defined breeding season.

Life Cycle

The Pen-Tailed Shrew is rare and difficult to capture so very little is known about its reproductive habits. It is known that they have two pairs of teats or nipples which suggest a litter size of one to four young. Other species of this order have gestations or pregnancies that last forty five to fifty five days. They also nurse their young, letting the young get stuffed then leaving them for up to forty eight hours before repeating the process. The mothers have a scent the spray on the nest that drives other shrews away. The young are ready to leave the nest when they are four weeks old. Whether these habits that are prevalent in other species of the pen-tailed shrew's order are the same in the pen-tailed shrew has not been confirmed.


Subspecies of the Pen-Tailed Tree Shrew are:

Ptilocercus lowii continentis
Ptilocercus lowii lowii

Interesting Facts

Tree Shrews have the highest brain to body mass ratio of any animal, even higher than humans


The Pen-Tailed Tree shrew is classified as least concern on the IUCN (International Union of Conservation of Nature and Natural Resources) red list of threatened species. This classification is the lowest and means the species has a large widespread, population and no current threats that would likely decrease its population in the foreseeable future.