“You’re blind as a bat!” We’ve all heard it. Myself particularly, while missing the most visible of objects. Naturally, as a biologist, I mused to myself: are bats really blind?
Most bats, especially the larger species, can see up to three times better than humans. Their optimal visual spectra is what humans would consider ‘pitch black,’ while their true tact lies in their ability to echolocate.
Ecolocation works by emitting a series of clicks, allowing bats to detect desired objects (such as prey) from the time and frequency of the reflected sound wave. This is aided by a number of morphological adaptions including their oversized ears, which funnel sound to be heard correctly. This adaptation continues to the inner each where the middle ear muscle (the stapedius) contracts to deafen the bat to its own ultrasonic call, which can range from 50-120dB. Luckily, we aren’t privy to these frequencies as they fall below the human hearing range; humans can detect sound waves to an upper boundary of 20kHz, while bat calls range from 20-200kHz.
Whilst the whistles and clicks of most bats originate from their mouths, a few species such as the Horseshoe Bat produce them from their nostrils, which have specially shaped structures to act as amplifier for their calls.
So, the next time a companion brands me as “blind as a bat,” I’ll stick my nose up at them, and thank them for comparing me to such a marvellous creature.
Featured Image: Wikimedia Commons
Last modified: 28th October 2020