Cephalopods are arguably the weirdest of all marine invertebrates. The name cephalopod literally translates to ‘head-footed’ in Greek, indicating just how strange members of this taxonomic class are, but nothing in their name indicates how incredibly intelligent they are. Their alien-like features are truly fascinating and cephalopods are commonly regarded as the most advanced of all invertebrates!
The weirdest one – nautilus (Nautilus pompilius)
Kicking off our list is the bizarre-looking nautilus, whose appearance resembles a cross between a snail and a shrimp. They are the only species of cephalopod to have retained their external shell, which means they cannot alter their appearance as well as their counterparts.
The invisible one – common cuttlefish (Sepia officinalis)
The deadly one – southern blue-ringed octopus (Hapalochlaena maculosa)
This species has one of the most potent venoms on the planet, 1000 times more powerful than cyanide, and there is no known antidote. The blue rings after which this species is named will only appear when an individual is disturbed and serve as a warning before it attacks. The helpless crab in this video finds this out the hard way!
The strangely familiar one – opalescent squid (Loligo opalescens)
You may have come into contact with this cephalopod more than any other – the opalescent squid is more commonly known to us as ‘calamari’. These small squids live in extremely large shoals and hunt by striking their prey with their tentacles.
The one-size-fits-all one – curled octopus (Eledone cirrhosa)
The ability of the curled octopus to transform and camouflage its body is truly fascinating – there is no gap too small or seaweed too colourful for this species! The curled octopus is also equipped with an ink jet they can utilise as a distraction when a predator is nearby. On top of all that, it also has an extremely toxic venom that it uses to paralyse its prey!
The colourful one – Carribean reef squid (Sepioteuthis sepioidea)
Commonly found in shallow reef waters, this intriguing species has enormous eyes and is known to have the largest eye-to-body ratio of the whole animal kingdom! Carribean reef squid communicate with each other by changing the colour of their skin.
The huge one – giant Australian cuttlefish (Sepia apama)
The giant Australian cuttlefish is largest cuttlefish species, reaching lengths of up to a metre. Despite its large size, this species it is a master of disguise and can easily blend in with its surroundings due to special pigment cells called chromatophores which allow it to change colour in an instant.
The even huger one – Humboldt squid (Dosidicus gigas)
A close relative of the giant squid, this species, also known as the ‘jumbo squid’, is a monster capable of growing up to 2 metres long and weighing over 50 kilograms! They can move at considerable speeds (up to 24km/h) and have been known to propel themselves out of the water and soar through the air to evade their predators which include whales, sharks, seals and swordfish.
The bright one – firefly squid (Watasenia scintillans)
This bioluminescent species is definitely deserving of a top 10 spot as it is responsible for one of the most spectacular light shows on the planet! Between March and June millions of firefly squid gather off of the coast of Japan, as well as hundreds of tourists, producing a natural spectacle like no other. The firefly squid also uses its bioluminescence to attract prey and select mates.
The strong one – North Pacific giant octopus (Enteroctopus dofleini)
Reaching lengths of up to 5 metres and weighing in at up to 50 kilograms, this monster octopus had to make the top 10! The photograph below is not photoshopped, this species does eat sharks! Its raw strength makes it capable of ripping apart shells and flesh with its tentacles or using its powerful ‘beak’ to make easy work of its prey. This, in tandem with its camouflaging talent, makes it a truly ferocious predator.
Have we missed out your favourite cephalopod? Let us know!
Will Powell, Arkive guest blogger