Leopard shark finds electric target ©Ivan Gonzalez.
Sharks and rays use their electric sense to detect prey buried under the sand.This picture is from a high-school project I mentored at Scripps Institution of Oceanography. Conor McClune built this platform over a calibrated electric dipole simulating prey. The concentric rings are to give us an idea of the shark’s detection distance. When the leopard shark turns sharply and attacks the target we record the distance and calculate the value of the electric field strength detected at the onset of the attack. Similar experiments gave the astonishing value of 5 nV/cm. That means that sharks can sense voltage differences of 0.000000005 Volts over a centimeter of their skin!