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Posts Tagged ‘sharks’

Last week, an article that featured in Current Biology was covered broadly in the media – by the  BBC and bloggers alike – which I am thrilled to see as it involves an animal I think is awesome. The Veined Octopus (Amphioctopus marginatus), from the same group (Mollusca) as snails, has blown existing theory on intelligence in invertebrates clean out of the water.

Octopuses are considered as intelligent as dogs

In a study spanning nine years from 1999  to 2008, researchers Julian Finn and Mark Newman from Museum Victoria in Australia spent 500 hours diving in Indonesian waters. They filmed the shenanigans of the soft-sediment dwelling octopus, and realised something unique was going on. The octopus was seen digging empty coconut shells out of the sand, emptying them with jets of water, stacking them and carrying them with a cumbersome gait now known as ‘stilt-walking’:

The shells are used as an instant shelter for the octopus – and are only used when required, often being carried as far as 20 meters across the sea floor. Stilt-walking is a novel method of transporting the shells, and leaves the octopus open to attack by predators. This deployment of the shell is a clear example of tool use.

Ants carry leaves - but they are not as canny with them

Where various ant species will collect and carry leaves, this is only in reponse to specific stimuli and not deployed – meaning this is the first-ever recorded case of tool use in invertebrates.

The use of tools is a benchmark of higher intelligence, previously only observed in mammals and birds.  Professor Jerry Coyne from the University of Chicago discussed this in his informative blog, Why evolution is true.  Although the greater intelligence of the octopus is well-known and debated over in biological circles, the actions of acquiring the coconut shells are the most complex ever recorded – and there have been a few.

It seems the Beatles were a fan of the octopus, too –

Observational learning is considered a sign of higher intelligence. In 1992, an experiment in Naples proved octopuses displayed key characteristic behaviours of this type of learning, when a group of captive octopuses were trained to grab a red ball over a white ball – after having watching previously trained octopuses do the same.

In 1997, an article by Doug Stewart for America’s National Wildlife Federation cites how a night biologist at the Seattle Acquarium heard a commotion and caught a 40-pound octopus slithering around on the floor, having smashed the quarter-inch-thick lid of its tank.

Octopuses can be pesky beasts

The article also notes: ‘Octopus literature is filled with tales of naturalists briefly leaving animals in open tanks and returning to find them scaling a bookcase, hiding in a teapot or expired on the carpet.’ There have been reports of octopuses boarding fishing boats, opening holds and stealing fish, and playing with bottles, by releasing them into currents of water and catching them.

The biology of the octopus is just as neat. If in danger, they can expel black ink, change colour in less than a second and, if they do get nipped by a predator and loose an arm,  they can grow a new one back. Expert in animal behaviour from Marine Biology Laboratory in Massachusetts, Roger Hanlon, told Stewart: “When it comes to camouflage, it’s the most capable organism on the planet without question.”

The blue ringed octopus - master of deception

Octopuses have a retractable beak like a parrot’s to kill their prey. They can even eat sharks:

But the intelligence of the Veined Octopus as represented by their canny use of coconut shells is still baffling. How has their cognitive ability evolved to this extent in the marine environment, where selective pressures are completely different to those influencing the evolution of terrestrial beings? How does a species known for being solitary know to mimic the actions of its contempories – what is the advantage of this?

I shall keep an eye on the way this debate shapes up. Meanwhile, here’s Jean Geary Boal, one of the scientists who worked on the Naples experiment. She’s got a bit of a soft spot for the soft things:  “It’s extremely easy to anthropomorphise octopuses. They make eye contact with you. They respond to you. They reach toward you. There’s just something mesmerising for people about octopuses.”

*nb – in researching this article, I found Octopi is not the plural preferred by the majority of  scientists.

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