They’re one of our ocean’s most enigmatic creatures, famed for their ability to change colour, shape and size.Cephalopods are remarkably adaptable, capable of living in the coldest depths, warmest shallows and some species can even "fly".

However, the characteristic they’re probably best known for is their almost unique ability to squirt ink when sensing an attack, creating a sort of smokescreen, which allows them to make their quick getaway.

squid
Left: 'Jewel squid’. Right top: ‘Blue-ringed octopus’. Right middle: ‘Giant Pacific Octopus’. Right bottom: ‘Football octopus’.

'Jewel squid' (Histioteuthis). These hang out in mesopelagic depths and are covered in light-emitting photophores. Photo: Nature Picture Library/Alamy Stock Photo

'Blue-ringed octopus’ (Hapalochlaena maculosa). Deadly! The most venomous octopus in the world. Image credit: WaterFrame/Alamy Stock Photo.

‘Giant Pacific Octopus’ (Octopus dofleini).  Found off the West coast of Canada, this is the largest octopus species in the world.  Photo: Alexander Semenov9.

‘Football octopus’ (Ocythoe tuberculata). This is an argonautoid octopus. It has a detachable hectocotylus and the male is dwarf compared to the female. Photo: Steve O’Shea AR.

While there are around seven hundred living Cephalopod species, with octopuses, squids and cuttlefish among the best known, modern science is still only beginning to grasp their array of adaptations. 

Octopus, Squid And Cuttlefish: A Visual Scientific Guide
Octopus, Squid And Cuttlefish: A Visual Scientific Guide

One scientist who’s currently at the forefront of trying to unlock the secret world of these fascinating marine animals is Professor Louise Allcock, who’s head of Zoology at NUI Galway. 

Louise is the co-author of a new book, called Octopus, Squid And Cuttlefish: A Visual Scientific Guide and she describes this trio as the most spectacular group of invertebrates on earth.

She joined Derek, Richard Collins and Eanna ni Lamhna in RTÉ's Galway studio. Listen back above.

- Words by Sinead Renshaw

Octopus, Squid And Cuttlefish: A Visual Scientific Guide, by Roger Hanlon, Louise Allcock and Mike Vecchione, is published by Ivy Press. 


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