Animals

Cambridge Scientists Crack Secrets of Cuttlefish’s ‘Cloak of Invisibility’

New research reveals the neural circuits that enable cuttlefish to change their appearance. Sunday, 18 February

By Jonathan Manning

As disappearance acts go, it’s faster than Harry Potter! The cuttlefish can transform its appearance in seconds, camouflaging itself against predators or concealing itself to surprise prey.

And now an international team of scientists has identified the neural circuits that enable cuttlefish not simply to change colour, like a number of reptiles and amphibians, but actually to change the physical texture of its skin to match its surroundings.

In the blink of an eye these cephalopods alter the physical texture of their skin to match the coarseness of surrounding rocks, coral or seaweed.

Dr Trevor Wardill from the Department of Physiology, Development and Neuroscience at the University of Cambridge, said, “The sea is full of strange and wondrous creatures, but there are few as bizarre and intelligent as octopuses and cuttlefish.”

How the cuttlefish achieves its invisibility is down to two sets of tiny muscular organs in its skin. The first, called ‘chromatophores’, change colour in response to a signal from the brain. The second set create bumps known as ‘papillae’, which can change the texture of the skin from flat to three dimensional.

Scientists from the University of Cambridge and Marine Biological Laboratory studied the nervous systems of the sea creatures and have just published their research in the journal iScience.

They found that the instruction signal from the cuttlefish’s brain is routed through a peripheral nerve centre called the stellate ganglion. This houses the giant axon system, as well as particular motor neurons that control the papillae on the cuttlefish’s outer surface. The nerve circuitry closely resembles the way a squids controls its skin iridescence.

Dr Paloma Gonzalez-Bellido, from the University of Cambridge, said, “This discovery is really interesting from an evolutionary point of view. It opens up the question of which came first: was the common ancestor to cuttlefish and squid able to camouflage themselves using papillae or express iridescence, or possibly both?”

 

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