for National Geographic News
Male bats turn up the bass to intimidate rivals and attract females, a new study shows.
The research reveals that greater sac-winged bats react more aggressively to more resonant low-frequency sounds than high-frequency sounds. The 2-inch (5-centimeter) long mammals live in Central and South America.
"We were really surprised to find low-frequency sound playing so big a role in so small a bat," said lead study author Oliver Behr of Friedrich Alexander University in Erlangen, Germany.
"It is going to be exciting further analyzing the behavior in future experiments," added Behr, who led the research this month described in the journal Behavioral Ecology and Sociobiology.
Behr also discovered that male bats that make lower frequency calls sire more offspring than their competitors—suggesting that bats with the deepest voices are most alluring to females.
(Related: "Bats Can Make Calls More Intense Than Rock Concerts" [April 30, 2008].)
A number of other mammals use threat displays to give rivals a sense of their power, experts say. Elk and bison, for instance, do this by bellowing.
Such calls—though loud and energy-intensive—pay off because they usually allow the animals to resolve conflicts without attacking one another.
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