Natures wonders: bat hunting navigation (Introduction)

by David Turell @, Friday, June 19, 2015, 15:38 (1554 days ago) @ David Turell

Bats are night time hunters and use radar (echolocation) to find insects flying at high speed:

http://www.sciencedaily.com/releases/2015/06/150619084612.htm

"Every night a bat puts in 600-700 kilometres of airtime. Flying low, the animals catch insects at speeds of around 40 metres per second. At night the bat uses its hearing to navigate its way to prey. Bats catch insects continuously using echolocation, an advanced navigation system.

"The bat emits ultrasonic waves with very high frequencies. Its calls are pitched at 20-100 kilohertz, a frequency that is too high-pitched for humans to hear naturally. Their sounds are reflected in the environment, hitting various objects and returning to the bat as echoes. The echo signals enable the bat to form a mental map of its surroundings.

"Different daytime flying pattern When bats on rare occasions fly during the day, they use their vision to navigate and fly in a straight line to their destination.

"Night-time flights are more elaborate than daytime ones. Bats continuously rise and dip in curved flight trajectories, using large movements to propel themselves.

"Noise from rain, wind and snow disrupts echo signals, making it harder for the bat to form a picture of its surroundings. The bat's big night-time movements also generate sound that disturbs the echo signals.

"But bats manage to catch their targeted prey despite poor weather conditions. Bar has recently researched how this is possible.

"'Bats are able to filter out the ambient noise around them using low-pass filtering. Useless sounds are cleared out, which makes conditions more transparent. The bat also has a highly developed sensorimotor system, which controls the mammal's movements. These characteristics enable the bat to move quickly and with incredible precision," says Bar."


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