Seahorses are Terrible Swimmers but Great Predators
upstart writes:
Seahorses are terrible swimmers but great predators:
Seahorses are fish that possess unique properties such as male pregnancy, square tail vertebrae, and, of course, a unique eating system. For most of the day, seahorses are anchored with their tail to seaweeds or corals with their head tilted downward, close to their body. However, when they detect prey passing over them, they lift their head at incredible speed and catch it. According to Prof. Holzman, while preying, seahorses turn their body into a kind of spring: Using their back muscles, they stretch an elastic tendon, and use their neck bones as a "trigger," just like a crossbow. The result is faster than even the fastest muscle contraction found anywhere in the animal world.
However, until now, it was not clear how the spring-loaded mechanism enabled seahorses to eat. Just [ask] anyone who tries to remove a fly from a cup of tea knows, water is a viscous medium and the fish needs to open its mouth to create a flow that draws the prey in. But how do seahorses coordinate snagging in prey with their head movement?
[...] [The] researchers [...] [photographed] their attack at a speed of 4,000 images per second, and using a laser system for imaging water flows. This measurement showed that the 'crossbow' system serves two purposes: facilitating head movement and generating high velocity suction currents-10 times faster than those of similar-sized fish.
Journal Reference:
Avidan, Corrine, Holzman, Roi. Elastic energy storage in seahorses leads to a unique suction flow dynamics compared with other actinopterygians [open], Journal of Experimental Biology (DOI: 10.1242/jeb.236430)
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