The giant Pacific octopus (Enteroctopus dofleini) grows bigger and lives longer than any other octopus species. The size record for this species was a specimen measuring 30 feet (9m) across and weighed more than 600 pounds (272 kg). All octopus are mollusks in the Class Cephalopoda, which means “head-feet”, but the body (called mantle) of an octopus is much more than a head; it contains vital organs like the gills, anus, gonads, ink sac, and a mechanism for jet-propulsion called the siphon. One thing the octopus doesn’t have, however, is a brain – at least not the kind we are used to. What we (and most other animals who have a brain) have is a centralized mass of grey matter that controls all other parts of our body. Octopus brains, however, as divided between a smaller central brain and 8 large ganglions at the base of each arm, which allows them move and act independently from the rest of the body. This means octopus arms literally have a “brain of their own” 🐙
Cephalopods are also champions of camouflage. An octopus can change both the colour and texture of their skin in milliseconds, imitate complex patterns, and they do it all while being colorblind! The mechanisms of how cephalopods can sense and match colour are not very well understood, but their amazing colour-changing abilities are made possible by an assembly of specialized components in their skin. These include chromatophores – colored pigment cells that expand and contract to produce colour and pattern. Iridophores are a subcategory of chromatophores that reflect light to generate iridescence. Texture is controlled by dermal muscles in the octopus’s skin that create a heavily textured look through papillation (i.e. wrinkling). Octopus use their skin to communicate, blend into the background, stalk prey, or avoid predators.