Ink Cloud Distracts Predators

overhead view of a camouflaged reef octopus as it leaves a trail of ink underwater

Biological Strategy

Octopods

AskNature Team

Image: Ria Tan / Flickr / CC BY - Creative Commons Attribution alone

Protect From Animals

Animals–organisms that range from microscopic to larger than a bus–embody a wide variety of harms to living systems, including other animals. They threaten through predation, herbivory, defense, and parasitism, and they compete for resources such as water, nutrients, and space. Any given living organism commonly faces threats from a variety of animals, requiring strategies that effectively defend from each. Trout and other bony fish, for example, escape predators by having scales made of very thin, flake-like pieces of bone covered with slippery mucus. They also have behavioral strategies such as camouflage, fast swimming, and twisting and turning to achieve release from a predator’s grip.

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Cephalopods

Class Cephalopoda (“head-foot”): Nautilus, squid, octopus, cuttlefish

Cephalopods are unique among mollusks, and even within the animal kingdom. They are lauded for their large brains and complex behaviors and are considered the most intelligent invertebrates. Among 800 species in 45 families, all are carnivorous and live in marine ecosystems. They all have a set of arms or tentacles, but only the nautilus retains an exterior chambered shell. Many species have chromatophores, which allow them to change color for defense, camouflage, or courting. They range from the size of a fingernail to just longer than a city bus (the mysterious giant squid).

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The ink cloud emitted by an octopus when threatened aids escape because it resembles the shape of the octopus.

“When their speed alone is not enough for safety, [cuttlefish] squirt a
cloud of dense, dark coloured ink that is synthesised in their bodies.
This ink surprises their predators for a few seconds, which is usually
enough for them to escape.” (Yahya 2002:104)

“Sometimes the ink cloud itself resembles the blobby shape of an octopus and acts as a decoy, allowing the octopus to escape while the predator eyes the blob.” (Crump 2005:109)

Crump, M. 2005. Headless Males Make Great Lovers & Other Unusual Natural Histories. University of Chicago Press, Chicago, IL. 199 pp.
Yahya, H. 2002. Design in Nature. London: Ta-Ha Publishers Ltd. 180 p.