Octopus & Squid

Cuddly creatures with more than two arms

The Common Octopus, Octopus vulgaris.

All cephalopods are venomous

A broad study of cephalopods - more commonly known as octopuses, cuttlefish and squid - has shown that they all possessed toxic proteins that performed functions such as paralysing the nervous system of prey.

The scientists analysed tissue samples from cephalopods from Hong Kong, the Coral Sea, the Great Barrier Reef and Antarctica.

The different species' genes were then studied for venom protection and it was found that a venomous ancestor produced one set of venom proteins, but over time additional proteins had added to the chemical arsenal.

Underview of octopus arms featuring the suckers attached to the aquarium glass
Underview of octopus arms featuring the suckers attached to the aquarium glass

Arms all over

Don't compare them to the simple rubber suction cups on kids' toy dart guns; these have their own elaborate muscular regulatory mechanisms. This diagram illustrates the internal structure of a single octopus sucker.

There are two main regions, an infundibulum (IN) on the attachment face of the sucker, and a deeper chamber called the acetabulum (A) (if you don't recall any Latin, "infundibulum" just means "funnel", while "acetabulum" is "vinegar cup"â anatomy is littered with funnels and cup-shaped structures, so these are actually very generic names).