Scalloped hammerhead shark

Photo: Kris Mikael Krister · CC BY

Scalloped hammerheads are one of the few shark species that form large daytime aggregations: schools of hundreds form around seamounts and islands for social interaction, cleaning, and possibly thermoregulation. The cephalofoil (hammer) contains an exceptionally dense array of electroreceptors that allows the shark to detect the minute electrical fields of prey buried in sand. El Bajo is one of 4 or 5 sites globally where consistent summer aggregations still occur; numbers have declined significantly since the 1980s due to targeted shark finning.