This doesn’t mean that octopuses do not distinguish ‘self’ from ‘other’. They clearly do – and they need to. For a start, they need to avoid getting tangled up with themselves. The suckers on an octopus arm will reflexively grip onto almost any passing object, yet they will not grip onto other arms from the same octopus, nor onto its central body. This demonstrates that octopuses are able, in some way, to discriminate what is their body from what is not. It turns out that this ability depends on a simple but effective system of taste-based self-recognition. Octopuses secrete a distinctive
...more
