In the video above, Brandon Moore from Louisiana Tech University is dissecting a freshly dead male alligator. You’re looking at the creature’s underside, near its hip area. As the sequence begins, Moore’s scalpel touches the alligator’s pelvic nerve. The metal makes the nerve fire and… well… just watch the video.

That’s the alligator’s penis—ten centimetres long, ghostly white, and surprisingly quick-moving. It flips out in an instant and just hangs there for a few seconds to greet a startled Moore, before twanging back inside just as quickly. I love that Moore back-steps and freezes. There’s no audio. I wish there was audio.

The video was a revelation to Diane Kelly from the University of Massachusetts, and the key to interpreting the