Dr Stein, who is a neurophysiologist at Illinois State University, told the BBC that they compared 11 marbled crayfish, spread through the pet trade to four locations on three continents.

We apparently have some new residents on the island, as several freshwater crayfish were found in the Devonshire Marsh area.

Each time, the owner panics, mistaking the freshly molted shell for a lifeless pet—only to find the crawfish alive, bigger, and with claws intact in the tank. The filmer jokingly said ...