Odd head of seahorse cloaks its sneak attacks

A dwarf seahorse can sneak unnoticed remarkably close to prey — less than a penny’s thickness away — thanks to the way the horsey head shape moves through water.

If they had just two or three milliseconds of warning, some of the seahorse’s prime prey, tiny crustaceans called copepods, would scoot away, says Brad Gemmell of the University of Texas at Austin. But a dwarf seahorse (Hippocampus zosterae) can strike even faster, within one millisecond. To succeed with its speedy strike, the seahorse somehow has to get within about a millimeter of its prey.

New imaging reveals a seahorse trick. As its head nears the prey, a zone of water above the front of the tip of its snout stays calm, Gemmell and his colleagues report November 26 in Nature Communications.  The trick fools copepods, which rely on antenna hairs to pick up the incoming whoosh