Thursday, November 28, 2013

Seahorses Get No Respect

These fragile creatures (Hippocampus. s) get no respect.  Yes, they are admired for their surreal beauty, and the males make great mothers, but when it comes to "street cred" seahorses are not on the A list. Even crabs seem more dangerous than a seahorse. A new study may change the human perception of seahorses as slow, awkward swimmers frozen stiff in an upright position. But as predators they are ferocious and ingenious. The elongated snouts make few ripples in the water to alert their tiny copepod prey. If a copepod detects water disturbances from a preditor it can jet away at speeds equivalent to a six foot human swimming 2,000 mph. Yet seahorses which are the slowest fish in the sea can regularly overcome the copepods speed advantage.

Seahorses catch their intended prey 90% of the time in calm water, an incredible success rate for a predator.  Dr. Brad Gemmell, of the University of Texas, Austin who authored the study, wanted to know how they did it. Syngnathid fish which include seahorses use a stealth technique termed pivot feeding that involves rapid movements at short range. A seahorse's arched neck acts as a spring allowing it to move its snout rapidly. The snout is shaped to minimize hydrodynamic disturbances so the strike [video] can be made over a distance of about 1mm without alerting the prey. This fact was discovered using 3D holography. Get close and don't hesitate works well for seahorses too.