If you have never seen the movie Thank You for Smoking, I would highly recommend it. There is a scene between a few of the main characters, which I wrote the dialog out for below (sorry no Youtube clip was available):
Bobby: Did you know that you can fool a breathalyzer test by chewing on activated charcoal tablets?
Polly (Alcohol spokesperson): Well, maybe we should change our slogan to: “If you must drink and drive, suck charcoal.”
Nick: Won’t the police ask about the charcoal in your mouth?
Bobby: There’s no law against charcoal…
Apparently, some fruit bats would do just fine on sobriety tests, no charcoal necessary. This research was actually the Master’s work of one of my graduate school friends, and I thought it would be fun to actually read her article and write a blog about it. Her primary article can be found here (open access), but National Geographic also did a short article about it if you do not want to read the full article.
Fruit bats feed on fruits in varying fermentation stages. Consequently, fruit bats consume the ethanol that was produced within the fruit from sugar conversion during the fermentation process. The researchers basically set up a sobriety test for fruit bats. This test would be comparable to police conducting the “straight line” test on suspicious drivers. To pass the test, the bats needed to flying through an enclosure with obstacles (hanging plastic chains) that were spaced about one wingspan apart. Some bats were fed plain sugar water, while others were given sugar water with ethanol. The researchers thought that the bats would show impaired flying and echolocation abilities. However, despite the fact that several bats had blood alcohol concentrations over 0.3 (0.08 BAC level is the legal limit for all US states), researchers found no significant differences in the bats’ ability to fly or echolocate while under the influence.
I thought the article was interesting because I had never thought about how fruit bats handle the alcohol within fermenting fruits. The article also explains similarities between how humans and bats handle alcohol. I found it interesting that both humans and bats can show differences in their abilities to tolerate alcohol. The authors did mention that not all bats possess a high alcohol tolerance. A study done in Israel showed that “Old World” bats (Megachiroptera) set in a similar test situation to the one mentioned above frequently crashed while under the influence. The ability of “New World” bats (Microchiroptera), such as those in my friend’s study, to better handle their alcohol is thought to be an important step in their evolution. I bet you did not think alcohol tolerance could be such an important part of survival to some animals! Maybe I should work on mine some more… with some nice fermented grape juice. 😉
Just for Fun: Baby Bat Burritos! – Australian Bat Clinic & Wildlife Trauma Center