Drinking you under the table

Bats could drink us under the table according to new research from Canada which tested how the creatures reacted to having their drinks spiked.

Fruit and nectar eating bats often eat fermented fruit and researchers from the University of Western Ontario and the University of Regina wondered how this affected their flight and echolocation. They believed that – considering the low body weight and amount of energy needed to keep the bat going – the fruit’s low alcohol content would cause the bats to become intoxicated.

Researchers first compared a group of control bats with a group who’d had their sugar water drinks spiked with 1.5% alcohol. The bats were made to drink the same amount per gram of body weight before being let loose to fly through an obstacle course. The researchers also recorded the bat’s echolocation calls.

However, rather than the alcohol-fed bats bumping into obstacles and taking longer to complete the course, they manoeuvred through the course with the same speed as the control group, and missed all obstacles in their path. Their echolocation calls were also unchanged.

The researchers said: “We found no significant differences in flight performance of echolocation behaviour between bats fed sugar water and bats fed ethanol, suggesting that wild frugivorous and nectarivorous phyllostomids (bats) tolerate ethanol at the concentrations we studied.”

Researchers also took saliva swabs from the bats before and after the test to determine their blood alcohol concentration. A large proportion of bats had concentrations over 100mg per 100ml of blood – enough to make most humans drunk.

Researchers believe there is a combination at factors at work: the bats are resistant to intoxication, they process the alcohol effectively and quickly or they recognise the smell of fermented fruit and only eat fruit that is not too far gone. The researchers think it’s likely that the bats are just hardcore drinkers.