One of the most unique features of bats is their ability to hunt through echolocation. This process involves the emitting of high-intensity sound from the bat's mouth, which then bounce back through the bat's ears and allow it to create a landscape of its surroundings through sound. Echolocation involves sounds between 14,000 and 100,000 Hz. Humans can only decipher sounds up to 20,000 Hz, which is why the process of echolocation is inaudible to them. While bats are the primary animal to use echolocation, it is also possessed by shrews as well as toothed whales.
Why bats have echolocation?
Bat in Flight
Not all bats have echolocation. In fact, echolocation is primarily found in microchiroptera bats (microbats), who feed on insects. Echolocation gives bats a significant advantage in feeding, as it allows them to hunt during the night hours. This gives bats access to food that no other predators consume. A few bat species that feed on fish use echolocation as well. They seek out disturbances or ripples in the water and then pounce on the fish that are usually swimming underneath.
Scientific discovery of echolocation
Bats have harnessed the powers of echolocation for over 50 million years, but the scientific discovery of echolocation has been a slow process occurring over the last few centuries. Since time immemorial, the prevailing belief had been that bats were able to fly at night because of magical, devil powers. However, Lazzaro Spallanzani, an 18th century scientist, began looking for other explanations for this phenomenon.
Spallanzani started his research by covering the eyes of bats and observing them attempt to fly across a room full of obstacles; he was surprised by their ability to clear the room without accident. Suspicious that bats were hunting without using their eyes, he blinded a number of bats, released them into the wild--where they returned to their roost on a nearby bell tower--and then located them and examined their stomachs. The bats had consumed several meals, despite being blind, confirming Spallanzani's hypothesis that they were using senses besides their eyes for hunting. When the Swiss zoologist Jurine heard abut this work, he plugged the ears of bats and witnessed that their sense of direction failed.
Despite this early work, scientists were still unsure how bats could navigate; they just knew they weren't using their eyes. In 1920, a British physiologist named Harding hypothesized that bats emit ultra sonic signals. This hypothesis was confirmed by the scientists Pierce and Griffin, who, in 1938, put bats in front of highly-sensitive sound recording equipment and found that they registered sounds of great intensity. Later research would show that bats emit sound pulses through the mouth. These pulses usually occur in the range of 10 to 30 sound pulses per second. However, when bats approach a landing spot or prey, the pulses can increase to between 50 and 100 pulses per second, so the bat can have a continually-updated sonic picture of its surroundings.
Ready to purchase a bat house? Then browse our huge online inventory of bat houses. Want to learn more about bats? Then check out some of the articles below.
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