Do animals such as crustaceans and molluscs have nervous systems?
Some do; others, like zooplankton, don’t. As with other animals (such as birds, fish, mammals and reptiles), some molluscs (octopi, squid and snails, among others) and crustaceans (like prawns, shrimps, crabs or lobsters) have nervous systems extending all over their bodies (with visceral, pedal and cerebral ganglia – that is, nerve knots). When we consider that having a nervous system is the basis for the capacity to feel, and in accordance with present scientific knowledge of this issue, it seems unreasonable to think these animals are not sentient.
