Roaring bats

Apr 30, 2008

Annemarie Surlykke from the Institute of Biology, SDU, Denmark, and her colleague, Elisabeth Kalko, from the University of Ulm, Germany, studied the echolocation behavior in 11 species of insect-eating tropical bats from Panamá, the findings of which are reported in this weeks’ PLoS ONE.

The researchers used microphone arrays and photographic methods to reconstruct flight paths of the bats in the field when these nocturnal hunters find and capture their insect prey in air using their sonar system. Surlykke and Kalko took this information as a base to estimate the emitted sound intensity and found that bats emit exceptionally loud sounds exceeding 140 dB SPL (at 10 cm from the bat's mouth), which is the highest level reported so far for any animal in air. For comparison, the level at a loud rock concert is 115-120 dB and for humans, the threshold of pain is around 120 dB.

Bats emit their echolocation calls at ultrasonic frequencies, i.e. above the human hearing range. This is necessary to get echoes from small insects, but the draw-back of high frequencies is that they do not carry far in air as they are attenuated faster than low frequencies. By estimating detection range for typical insect prey, Surlykke and Kalko conclude that these extreme intensities are essential for the bats as they serve to counteract attenuation.

This is the first comparative field study of bat echolocation sounds focusing on intensity and the results revealed, very interestingly, that although signal intensities (and frequencies) of bats vary widely, they appear to converge on similar detection ranges, because the bats emitting the highest frequencies were also the bats emitting the highest intensities. Thus, the study illustrates the value of an interdisciplinary approach combining bat biology, ecology, behavioral biology and acoustics.

Citation: Surlykke A, Kalko EKV (2008) Echolocating Bats Cry Out Loud to Detect Their Prey. PLoS ONE 3(4): e2036. doi:10.1371/journal.pone.0002036

Source: Public Library of Science

Explore further: Healthy humans make nice homes for viruses

add to favorites email to friend print save as pdf

Related Stories

Index ranks Japan Asia's most efficient innovator (Update)

20 minutes ago

A new index ranks Japan as the most efficient among Asian countries in turning the building blocks of creativity into tangible innovations that benefit their economies and people while Myanmar, Pakistan and Cambodia are least ...

Nevada governor enacts Tesla tax break package

10 minutes ago

Calling it one of the most important pieces of legislation in Nevada history, Gov. Brian Sandoval has signed into law an unprecedented package of incentives to bring Tesla Motors' $5 billion battery factory ...

Recommended for you

Transparent larvae hide opaque eyes behind reflections

7 hours ago

Becoming invisible is probably the ultimate form of camouflage: you don't just blend in, the background shows through you. And this strategy is not as uncommon as you might think. Kathryn Feller, from the University of Maryland ...

Peacock's train is not such a drag

8 hours ago

The magnificent plumage of the peacock may not be quite the sacrifice to love that it appears to be, University of Leeds researchers have discovered.

Iberian pig genome remains unchanged after five centuries

14 hours ago

A team of Spanish researchers have obtained the first partial genome sequence of an ancient pig. Extracted from a sixteenth century pig found at the site of the Montsoriu Castle in Girona, the data obtained indicates that ...

User comments : 0