This is a video from BBC Earth about the mating rituals of hammerhead sharks, which, unsurprisingly, does involve a fair amount of nailing. Some more info while I outwardly pat myself on the back for that but inwardly just get the a deep case of the sads:
The hammerheads come from all different directions and gather, swim around each other in big circles in a wonderful sort of balletic association. At the very centre of this big mass of hammerheads are the oldest, most mature females. The younger sharks swim around them. When the males come in to mate, they've got to weave and wind their way through this mass of hammerheads, so only the strongest, fittest males will get to mate with the females in the centre.
We are only just beginning to understand the purpose of this mass congregation, so the more scientists dive down there, the more they're understanding its importance. It's a very special place, and a very important behaviour, that needs to be protected. The Galapagos is one of the last jewels of this blue planet of ours. It really needs extra protection of ours oceans to make sure that that doesn't disappear for ever. It was extraordinary.
Fascinating. Obviously, if I was a young hammerhead shark there is an approximately zero percent chance I would ever make it to the middle of the circle to mate with a mature female. And I'm not just saying that because I recently passed out playing Red Rover before I even made it halfway to the other line, but it was a bad idea playing on asphalt instead of grass.
Keep going for the video.
Thanks to Christina D, who wants to know how many merpeople died to get us this footage.