The more I learn about bats, the more I am impressed at the abilities of these mammals. I had taken the phrase ‘blind as a bat’ literally and thought that bats depended entirely on echolocation to navigate. Christie Wilcox sets me straight and says that bats use both vision and echolocation to get around, using each for specific purposes.
Many bats are active at night and use a sonar-like sense (echolocation) to find their prey, which is probably where the myth that they are blind came from. But all 1,100 bat species can see just fine, and in many cases, their vision is quite good.
Rather than rely entirely on their hearing, a fascinating study published in Frontiers in Physiology in 2013 showed that even nocturnal microbats likely use a combination of vision and echolocation to “see.” The scientists from Tel Aviv University studied two bat species which, like many bats, awaken and begin to hunt just after the sun goes down. By glueing special recorders to bats, they were able to determine that the bats use echolocation regardless of light levels, dismissing the notion that they switch to sound as darkness sets in. Instead, they use it all the time, because it’s better at detecting small, moving objects. “Imagine driving down the highway: Everything is clear in the distance, but objects are a blur when you pass them,” lead author Arjan Boonman told Popular Science. “Echolocation gives bats the unique ability to home in on small objects–mostly insects–while flying at high speeds.” Their eyes, on the other hand, are key for general orientation. “We find that echolocation is better than vision for detecting small insects even in intermediate light levels,” write the authors, “while vision is advantageous for monitoring far-away landscape elements in both species.”
But in addition to setting the record straight on bat navigation systems, Wilcox also takes Neil deGrasse Tyson to task for glibly tweeting stuff about biology in general and bat vision in particular that is wrong, saying that this is not the first time that the popularizer of science has gone astray.
Many know Neil deGrasse Tyson for his pithy, humorous science tweets, which are a part of his greater science communication strategy. As of late, though, scientists have become quite vexed with NDT’s 140-character stylings, as he’s been foraying outside his planetary expertise and into biological phenomena, getting the facts wrong every time. First, there was his mistaken evaluation of evolutionary drivers and how sex works, excellently torn apart by Emily Willingham (a Ph.D. scientist whom Tyson then condescendingly called “a woman who has a blog”, prompting some to suggest he be referred to as just a “man with a twitter”). Then came his misunderstanding of genetics and deleterious alleles, which was ripped apart by Jeremy Yoder (another Ph.D. scientist).
When scientists step outside their area of expertise, they should exercise caution, especially if a lot of people listen to them. Tyson should take heed.