Recently PLoS ONE featured a fascinating new study on bat echolocation. The authors (one of which is named Annemarie . . . we are a rare breed, you know!) analyzed the intensity and frequency of search signal calls during foraging, and they discovered that bats emit surprisingly loud sounds, reaching over 140 decibels in some cases! (For some context, frequent exposure to music louder than only 85 decibels puts humans at risk for premature hearing loss). That is some powerful sound output from very tiny creatures.An important feature of bat calls is that intensity and frequency correlate with each other. This is important, because higher frequency calls are also more highly attenuated. Controlling intensity, and thus frequency, of their calls allows bats to adjust their search strategy for ideal detection distances for their prey. To put it another way, the type of prey they are seeking constrains the effective range of intensities for their calls. Head over and read the paper yourself for the full details!
Surlykke, A., Kalko, E.K., Giurfa, M. (2008). Echolocating Bats Cry Out Loud to Detect Their Prey. PLoS ONE, 3(4), e2036. DOI: 10.1371/journal.pone.0002036
3 comments:
Very cool paper, isn't it?
Another cool thing: bat ears have a special adaptation so that when they're making that super loud sound, they can sort of "plug" their ear for that split second to avoid deafening themselves. Then as soon as they make the noise they unplug to listen for echos.
That's one of my favorite facts about bats! There is a mechanism that lets them disconnect the bones in their ear for the split second that they are emitting their calls, it's a physical link between the two actions, not exactly a plug, but it's pretty cool!
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