According to an article in the Montreal Gazette, bats are steady flyers — even while intoxicated. Reporting on an article from the journal PLoS One, the Gazette delves into Central American bats that eat fermented fruit and nectar with a high alcohol content, and their ability to fly a straight line, so to speak.
Scientists expected that the creatures' flight would be impaired by the boozy berries, but they were surprised to discover "none of the bats showed any trouble maneuvering through an obstacle course — even with blood-alcohol levels that far exceed the legal limit for humans." To conduct the research, University of Western Ontario biology professor Brock Fenton and his team gave 106 bats spiked fruit juice or regular fruit juice. They then gave the bats mini breathalyzers (actually saliva swipes) before putting them through an obstacle course.
The Gazette quotes Fenton, saying, "Drunk or sober, big or small, the bats flew through the obstacle course without a problem." In addition to not having impaired flying, the bats were able to use a built-in sonar system to get around in the dark and interpret sound waves. This research indicates that bats could have an "evolutionary advantage" over other species, and Fenton theorizes that unimpaired species would have access to more types of foods because of this advantage.
Earlier research on bats showed different species were more sensitive to alcohol than the six species Fenton studied, which indicates that different bats have different tolerance for alcohol — much like humans. Next up for Fenton is an application for a Discovery grant from the Natural Sciences and Engineering Research Council of Canada. He hopes to use the funds to travel to Africa and study different bat species' tolerance for the hard stuff.