Pen-tailed Treeshrew

The pen-tailed treeshrew is the sole living member of Ptilocercidae. It has a pointed snout, large eyes, grey-brown body and a long mostly naked tail ending in two rows of feather-like hairs. Unlike typical treeshrews, it is strongly nocturnal (Mammal Diversity Database; species-level ecological studies).

It inhabits lowland rainforest on the Malay Peninsula, Sumatra and Borneo. An agile climber, it feeds on arthropods and repeatedly visits bertam palms for naturally fermented nectar, tolerating alcohol concentrations that would impair many mammals. Tree hollows provide day refuges (species-level field studies). It is Nationally Data Deficient (Thailand Red Data 2025).