Crabs may feel and remember pain

New research suggests that crabs not only suffer pain but that they retain a memory of it. The scientific study applied mild electric shocks to hermit crabs to determine if they could 'feel' pain.

Hermit crabs have no shell of their own so inhabit other structures, usually empty mollusc shells.

In the research, wires were attached to shells to deliver the small shocks to the abdomen of some of the crabs within the shells. The only crabs to get out of their shells were those which had received shocks, indicating that the experience is unpleasant for them.

The research suggests that this response is not just a reflex, but that central neuronal processing takes place.

Hermit crabs are known to prefer some species of shells to others and it was found that that they were more likely to come out of the shells they least preferred.

The main aim of the experiment was to deliver a shock just under the threshold that causes crabs to move out of the shell, to see what happened when a new shell was then offered.

Crabs that had been shocked but had remained in their shell appeared to remember the experience of the shock because they quickly moved towards the new shell, investigated it briefly and were more likely to change to the new shell compared to those that had not been shocked.

Original article here.