Q: Do live lobsters really scream or screech when they hit hot water? AskFN: They don't. Lobsters do not have vocal cords and they communicate via pheromone. However, they do emit a squealing noise, which is the sound of the trapped seawater between the shell and the body escaping from the body as it heats up.
Though it's a little more hands-on than boiling, here's the best way to make sure a lobster feels as little pain as possible: put the lobster belly-up on a cutting board, then insert a sharp, heavy knife into its midsection, between the legs. Immediately push down on the knife to split the lobster's head in half, then cook as planned.
- Food Network Kitchens