What Are You Doing In There, Fish?

Remoras evolved to be clingy. The suction cup on their foreheads allows them to attach to larger animals like fridge magnets. Remoras hitch free rides on creatures of their choosing: sharks, rays, whales, dugongs, turtles, even parrotfish. But it has been traditionally assumed that the remora's approach to such symbiosis was mutually beneficial to both parties: The fish eat parasites off their hos