|Range||southern Thailand, the Malay Peninsular, Borneo and some Indonesian islands.|
Pen-tailed treeshrews are the only known wild mammals that consume alcohol every night. According to a study of treeshrews in Malaysia they spend several hours per night consuming the equivalent of 10 to 12 glasses of wine with an alcohol content of up to 3.8% drinking naturally fermented nectar of the bertam palm. This nectar contains one of the highest alcohol concentrations of all natural foods. Pen-tailed treeshrews frequently consume large amounts of this nectar while showing no signs of intoxication. 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. Their ability to ingest high amounts of alcohol is hypothesized to have been an evolutionary adaptation in the phylogenic tree. However, it is unclear how pen-tailed treeshrews benefit from this alcohol ingestion or what consequences of consistent high blood alcohol content might factor into their physiology.