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The pen-tailed treeshrew (''Ptilocercus lowii'') is a treeshrew native to southern Thailand, the Malay Peninsular, Borneo and some Indonesian islands. It is the only species in the genus ''Ptilocercus''. All other treeshrew species are grouped in the Tupaiidae family. It is considered the closest relative of extant primates.〔Janecka, J. E., Miller, Thomas, W., Pringle, H., Wiens, F., Zitzmann, A., Helgen, K. M., Springer, M. S. and Murphy, W. J. (2007). Molecular and Genomic Data Identify the Closest Living Relative of Primates. Science 318: 792.〕 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. == Taxonomy and Evolutionary History == Ptilocercidae is a family within the order Scandentia. Numerous morphological and genetic differences support the classification of Ptilocercidae as a separate family from the rest of the tree shrews which diverged around 63 million years ago. Interestingly, tree shrews were considered a close relative of primates, but recent genetic data has concluded that Dermoptera, not Ptilocercidae is the appropriate out-group for study of primates. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pen-tailed treeshrew」の詳細全文を読む スポンサード リンク
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