In collaboration with the University of Chicago, UCLA and others, the genome sequence was solved. Apart from the some 33.000 genes, a remarkable finding are the octopus’s half a billion neurons — six times the number in a mouse — two-thirds spill out from its head through its arms, without the involvement of long-range fibres such as those in vertebrate spinal cords.

Nature doi:10.1038/nature.2015.18177