Lobsters lack the brain anatomy needed to feel pain, said Ayers, who builds robots modeled on lobster and sea-lamprey neurobiology. Lobsters and other crustaceans are often swallowed whole by predators, he added, so they never needed to evolve the ability to detect pain from, say, warming water or an electric shock.

A new animal protection law in Switzerland requires that lobsters be stunned before being cooked. Animal rights activists and some scientists argue that lobsters' central nervous systems are complex enough that they can feel pain. There is no conclusive evidence about whether lobsters can feel pain.