The Amazing Archer Fish

The archerfish (or archer fish) are a family (Toxotidae) of fish known for their habit of preying on land based insects and other small animals by literally shooting them down with water droplets from their specialized mouths. Archerfish are remarkably accurate in their shooting; adult fish almost always hit the target on the first shot. They can bring down an insect that includes grasshoppers, More..[3] spiders and butterflies on a branch of an overhanging tree,[4] 3 m above the water’s surface.[5] This is partially due to their good eyesight, but also having ability to compensate for light refraction when aiming for their prey.[6] They do this by swimming directly, hovering under the prey, where the distortion is the least. However, experimentation has shown that the Archerfish can hit prey at greater angles than a perpendicular angle without losing accuracy. When an archerfish selects its prey, eyes are focussed on it and sticks its snout just above the surface, squirting a jet of water at its victim. It does this using the narrow groove that is formed in the roof of its mouth. It presses its tongue against this groove to form a narrow channel, then contracts its gill covers to force a powerful jet of water through the channel. The resulting jet of water can be up to 2-5 m long, but their accuracy only allows them to shoot insects 1-1.5 m away. The fish can alter the power of the shot for prey of different sizes. If the first shot does not knock the victim into the water, the archerfish will keep trying. Young archerfish start shooting when they are about 2.5 cm long, but are inaccurate at first and must learn from experience. During this learning period, they hunt in small schools. This way, the probability is enhanced that at least one jet will hit its target. However, archerfish prefer to leap out of the water and grab the insect in their mouth if it happens to be within reach. Individuals typically prefer to remain close to the surface of the...

Channel: LiveLeak Video Length: 0s Date Found: Wed, Jul 28 2010 2:41 AM Category: Educational Date Produced: Wed, Sep 16 2009 12:00 AM View Count: 0