Ampullae of Lorenzini

Ampullae of Lorenzini are specialised electroreceptors found primarily in elasmobranchs (sharks, skates, rays). They appear as small pores on the snout and around the mouth. Each pore leads via a jelly-filled canal to a sensory ampulla (flask-shaped sac) containing hair cells. They detect the extremely weak bioelectric fields (as low as 0.01 μV/cm) generated by the muscle contractions of buried or hidden prey. They can also detect magnetic fields, possibly aiding in navigation. Named after the Italian anatomist Stefano Lorenzini (1678).

A hammerhead shark's wide, T-shaped head increases the baseline between its ampullae, allowing more precise electrolocation of stingrays buried under sand.