When they fancy a change of scene, the sea creatures balloon up and hitch a ride on ocean currents, floating and bouncing around like tumbleweeds of the sea.

Sea cucumbers (also dubbed sea slugs, because of their unhurried nature) were thought to be capable of swimming long distances only during their larval stage, like most bottom-dwelling sea creatures. After becoming adults and settling down, they either crawled, or—if a predator was lurking around—crawled slightly faster.

But it seems they've been hiding a far more efficient mode of transport. By flooding their bodies with water, they reduce their density until they’re buoyant, detaching from the floor and opening themselves up to the mercy of the sea. (And at least one, Enypniastes eximia or