The pen-tailed tree-shrews have a taste for "bud"
A tiny tree-shrew that lives on alcoholic nectar could - pound for pound - drink the average human under the table, scientists have discovered.
Malaysia's pen-tailed tree-shrew waits until nightfall to binge on fermented nectar from the bertam palm.
The animal could give insights into how humans' alcohol tolerance first evolved, the scientists say.
The team has published details of its work in the journal Proceedings of the National Academy of Sciences.
Despite the shrews' small size, they are no lightweights when it comes to their alcohol intake.
Nectar from the flower buds of the bertam palm is fermented to a maximum alcohol content of up to 3.8%.
Each bud is a miniature brewery, containing a yeast community that turns the nectar into a frothy beer-like beverage.
Yet the animals, which are about the size of a small rat, do not seem to get drunk at all, researchers say.
Tree-shrew 'boozes' on nectar
Frank Wiens, from the University of Bayreuth in Germany, and colleagues confirmed the animals' high alcohol consumption by analysing their hair.
Chemicals in the hair samples showed that on any given night, a tree-shrew had a 36% chance of being drunk by human standards.
The shrew's resistance to intoxication suggests its body must have an effective mechanism for breaking down alcohol.
This should not come as too much of a surprise: scientists believe the animals - which are distant relatives of humans - have had 55 million years of evolution to adapt to their boozy lifestyle.
The researchers used radio tags to track the creatures on their crawls and recorded video of their feeding sessions.
Humans may even preserve a relic of the shrews' love of alcohol that has lasted through millions of years of evolution.
In their PNAS paper, the scientists wrote that the pen-tailed tree-shrew is "a living model for extinct mammals, representing the stock from all extinct and living tree-shrews and primates radiated".
They added: "Therefore, we hypothesise that moderate to high alcohol intake was present early on in the evolution of these closely related lineages."
The researchers also filmed a primate known as a slow loris feeding from the bertam palm.
The palm produces nectar year-round on a complex schedule that appears to maximize pollination by small mammals.
Slow loris fancies a tipple