Don't Get Your Octopus in a Twist

The octopus is certainly amongst the most intelligent of invertebrates but its 8 arms have an apparently simple way of controlling the suckers. Hochner et al  at the Hebrew University of Jerusalem have discovered that a substance in the skin prevents the suckers fixing on another part of the animal's own body (including another tentacle). These molluscs will sometimes treat amputed arms (that can be regrown) as food but are less likely to gobble one of their own severed limbs unless the skin is removed. It appears that a chemical (or chemicals?) in the skin prevents activation of the suckers (it must be an individual characteristic).