[1] The pen-tailed treeshrew occurs from southern Thailand and the Malay Peninsula to northern Sumatra, Siberut, Bangka Island and northwestern Borneo.

[2] Pen-tailed treeshrews studied in Malaysia spent several hours per night consuming naturally fermented nectar of the bertam palm.

The pen-tailed treeshrews did not show any signs of intoxication, although they frequently consumed large amounts of this nectar, equivalent of 10–12 glasses of wine adjusted to body weight with an alcohol content up to 3.8%.

Measurements of a biomarker of alcohol dehydrogenase suggest that they may be metabolizing it by a pathway that is not used as heavily by humans.

Numerous morphological and genetic differences support the classification of the Ptilocercidae as a separate family from the rest of the treeshrews which diverged around 60 million years ago.