Here's a really lovely piece of journalism: Paul and Michael Albert, a writing-and-photography team, went kayaking in the sea of Cortez to witness an enormous school of mobulidae breaching the surface -- and leaping into the air like dolphins. Mobulidae, a family that includes both manta rays and mobulas, grow several feet in width, so their aerial leaps were pretty stunning:

Whoosh! Without warning, a mobula emerges from below the surface, its long flat body glistening in the evening light and whip for a tail trailing behind. Flap, flap, flap, maybe a somersault or two, and then smack! It happened again and again. Single flips. Straight-up belly flops. Double flips. I see a single mobula leap a few times in succession; others leap only once and then disappear. I witness mobulas partially emerging from the water, one third of the wingtip still immersed, and rotate around that tip. Sometimes, I don't even see that. All that is visible is the swirl of water left behind. Notarbartolo di Sciara writes that when he was in the Sea of Cortez some twenty years ago, he even observed triple flips. According to him, some mobulas leap at heights of up to two times their disc width or up to six feet high.

Why precisely do mobulas jump out of the water? No-one's sure, but as the Alberts note, some scientists speculate that the jumps could be accidental -- artifacts of the creatures' feeding patterns, which involve swimming tight circles around their prey. Swim too close to the surface, and boom: Ya wind up in the air. Others suggest that it could be to dislodge other sea creatures that attach to their bodies. Perhaps most intriguing is the speculation that maybe it's just play -- because mobulas have extremely large brains for their bodies, and the ratio is nearly that of most mammals.

(Thanks to Boing Boing for this one!)