Boozy tree shrews avoid fermented fruit hangovers
28 July 2008 | New Scientist
We have distant cousins who regularly guzzle alcoholic floral nectar without regretting it the morning after.
Pen-tailed tree shrews, which are related to the ancestors of primates, eat giant flower clusters of the stemless bertam palm in the rainforests of Malaysia.
Sugars in the palm's floral nectar ferment in the warm, moist environment, producing alcohol in concentrations up to a beer-like 3.8% with a mean concentration of about 0.6%.
As the nectar is an essential part of the shrews' diet, their taste for alcohol may help us understand the evolutionary forces that drive humans to drink, argues Frank Wiens of the University of Bayreuth, Germany, who carried out the study.
The alcohol content of the nectar is no accident. The flower structure fosters fermentation, apparently to attract mammalian pollinators.
The tree shrews do not seem to get drunk, although they consume enough alcohol to be intoxicated about a third of the time if they had a human-like metabolism. Their fur reveals the key to their sobriety – a metabolic byproduct called ethyl glucuronide (EtG).
Tree shrews seem to convert much of the alcohol they consume into EtG, which ends up in their fur. The compound is seen at levels normally found only in severely alcoholic humans although humans convert only a little alcohol into EtG.
"It's a beautiful example of the natural biology of alcohol consumption, which people have totally neglected in alcohol research," says Robert Dudley of the University of California at Berkeley.
Dudley has previously suggested that our taste for alcohol may be an "evolutionary hangover" from our fruit-eating primate ancestors, who developed a taste for fermented fruit.
Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0801628105)
Tree shrews could drink humans under the table
30 July 2008 | New Scientist
OUR distant cousins' taste for alcohol may help us understand the origins of our own love for it.
Frank Wiens of the University of Bayreuth, Germany, observed tree shrews - which are related to ancestral primates - regularly sipping nectar from bertram palm flower clusters, as an essential part of their diet.
Sugars in the nectar ferment in the warm, moist environment of the clusters, native to south-east Asia, producing alcohol concentrations of up to 3.8 per cent, similar to beer. The mean alcohol content is around 0.6 per cent - still enough to stimulate the shrews' alcohol receptors (Proceedings of the National Academy of Sciences, in press).
If the shrews had a human-like metabolism, at this rate, they would be intoxicated for about a third of their lifetime. Fortunately, shrews rid their bodies of alcohol much faster than humans, dumping a breakdown product of alcohol into their hair.
"It's a beautiful example of the natural biology of alcohol consumption, which people have totally neglected in alcohol research," says Robert Dudley of the University of California at Berkeley. He says further studies could cast light on why people are so fond of alcohol, and possible ways to reduce its impact.