Editing Animal echolocation (section)

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{{short description |Method used by several animal species to determine location using sound}}
[[File:Animal echolocation.svg|thumb|upright=1.8|A depiction of the ultrasound signals emitted by a bat, and the echo from a nearby object]]

'''Echolocation''', also called '''bio sonar''', is a biological [[active sonar]] used by several [[animal]] groups, both in the air and underwater. Echolocating animals emit calls and listen to the [[Echo (phenomenon) |echoes]] of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for [[animal navigation |navigation]], [[foraging]], and [[predation|hunting prey]].

Echolocation calls can be [[Frequency modulation|frequency modulated]] (FM, varying in pitch during the call) or constant frequency (CF). FM offers precise range discrimination to localize the prey, at the cost of reduced operational range. CF allows both the prey's velocity and its movements to be detected by means of the [[Doppler effect]]. FM may be best for close, cluttered environments, while CF may be better in open environments or for hunting while perched.

Echolocating animals include [[mammal]]s, especially [[odontocetes]] (toothed whales) and some [[bat]] species, and, using simpler forms, species in other groups such as [[shrew]]s. A few bird species in two cave-dwelling bird groups echolocate, namely [[cave swiftlet]]s and the [[oilbird]]. 

Some prey animals that are hunted by echolocating bats take [[Anti-predator adaptation|active countermeasures]] to avoid capture. These include predator avoidance, attack deflection, and the use of [[Ultrasound|ultrasonic]] clicks, which have evolved multiple functions including [[aposematism]], [[Batesian mimicry|mimicry of chemically defended species]], and echolocation jamming.