Thursday, November 20, 2014

Bats Jamming for Food

Mexican free-tailed bat - Wikimedia
In a previous blog we discussed how tiger moths elude bats by jamming their sonar. Bats have poor eyesight and hunt by echo location, sending out high pitched sounds that bounce off objects.  They can judge the size and speed of prey with this.  Tiger moths can produce a series of high speed clicks that confuse the bats.  "Since the attack sequence of a bat lasts less than a second, the moths have to react fast.  Fortunately, the moths can produce up to 450 clicks in one-tenth of a second."*

While studying this phenomenon, this same team of scientists discovered that bats can jam the signals of other bats competing for their prey.  A story from  Livescience.com reports that William Conner, a biologist at Wake Forest University, discovered a strange sound that Mexican free-tailed bats made only when another bat was homing in on a moth they were competing for.
"Competition for food can be fierce, and Mexican free-tailed bats emit a special call that can interfere with the sonar of other bats that are pursuing a meal. "They get into amazing aerial dogfights," said study leader William Conner, a biologist at Wake Forest University in Winston-Salem, North Carolina. "One will jam the other, and the other will jam back."
The bats would produce a "terminal buzz" just as they were about to capture their prey.  When the researchers played the interference sound, the bat was 86% more like to miss the prey.  Do other animal species use similar tricks?  Stay tuned for further research.


Other news from the bat world highlights the danger of wind turbines to bats.  They are apparently drawn to them by confusing them with very tall trees.  Birds face their greatest danger when the blades are turning at high speeds.  Although they look slow as we drive by them, the tips of the blades reach between 138 to 220 mph.  Bats are attracted when they are moving slowly, apparently avoiding the high speeds which create greater air turbulence.  Details at this link.

* More on moth jamming bats at Discovermagazine.com. 

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