To demonstrate how smart an octopus can be, Piero Amodio points to a YouTube video. It shows an octopus pulling two halves of a coconut shell together to hide inside. Later the animal stacks the shells together like nesting bowls and carts them away.“It suggests the octopus is carrying these tools around because it has some understanding they may be useful in the future,” said Mr Amodio, a graduate student studying animal intelligence at the University of Cambridge in Britain.