for National Geographic News
A taste for naturally fermented palm "beer" has turned a tiny Malaysian mammal into a chronic boozer, a new study shows.
The pen-tailed tree shrew is the first non-human mammal known to display alcoholic behavior.
What's more, the rat-size animal never gets drunk during its nonstop jungle jamborees.
(Read: "Elephants Drunk in the Wild? Scientists Put the Myth to Rest" [December 19, 2005].)
Because the species is considered similar to the ancient ancestors of all primates, its 55-million-year bender suggests that our own taste for alcohol might predate the known advent of brewing some 9,000 years ago.
"The circumstances in which these tree shrews consume alcohol could be similar to past scenarios of human evolution in pre-primate or early primate stages [and] could somehow be a link to human alcohol consumption," said study lead author Frank Wiens, a biologist at the University of Bayreuth, Germany.
Wiens and colleagues' findings were published in Proceedings of the National Academy of Sciences.
The flowers of the bertam palm produce nectar which naturally ferments—with the aid of several yeast species—to a 3.8 percent alcohol strength, similar to that of many beers.
Because the plant flowers nearly year-round, its rain forest bar is always open, and the pen-tailed tree shrew—along with several other local mammal species—are regulars.
The animals spend an average of two hours per night sipping the nectar, which appears to be their primary food source. To test the animals' alcohol consumption, Wiens and colleagues tested the animals' hair samples for ethyl glucuronide and found that the tree shrews consume alcohol at rates that would be dangerous to most mammals.
The tree shrews appear to have more efficient ways of metabolizing alcohol than humans, so they avoid getting drunk. Inebriation would be dangerous for small, potentially tasty mammals, Wiens said.
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