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Originally published March 18 2014

In spite of their seemingly 'simple' nervous systems, squid and octopuses possess complex intelligence

by David Gutierrez, staff writer

(NaturalNews) In general, biologists tend to think of vertebrates as both more complex and more intelligent than invertebrates. However, the class of animals known as cephalopods, which includes squids and octopuses, challenges many of those assumptions. These animals are so intelligent that they call into question many ideas about the biological underpinnings of intelligence.

Because cephalopods are hard to observe in the wild and because their nervous system is organized in a fundamentally different fashion from that of vertebrates, it can be hard to perform empirical tests on their intelligence. However, observational studies have amassed enough evidence of intelligence that these animals are now widely considered to be the most intelligent of all invertebrates (and potentially more intelligent than many vertebrates).

For example, in contrast with most other mollusks (a group of animals that includes not just cephalopods but also snails and shellfish), all cephalopods actively hunt down and capture prey. The Humboldt squid has been shown to exhibit cooperative hunting techniques involving sophisticated communication. Many cephalopods are capable of changing the color and pattern of their skin, an ability that appears to be used not just for camouflage but also for fairly complex communication. For example, the Caribbean reef squid is able to change the color patterns of the skin on two separate sides of its body at the same time, in order to communicate with two separate individuals simultaneously.

The motor and problem solving skills of cephalopods are also highly suggestive of intelligence. For example, various octopuses have been observed gathering coconut shells over large distances, then bringing them together and building shelters out of them. Octopuses have also been known to steal captive lobster from human traps, as well as to climb onto fishing boats and feast on dead and dying crabs.

Sociality, another characteristic that correlates highly with intelligence, appears to be universal in cephalopods. In fact, cephalopods are so highly social that, when cut off from others of their own kind, many of them will actually join schools of fish.

Tests have also shown that cephalopods have well developed senses and excel in spatial and navigational learning. Their brain-to-body-mass ratio is actually higher than that of most cold-blooded vertebrates. Like vertebrates, they protect their brain inside a type of skull, although in cephalopods that cranium is made out of cartilage rather than bone.


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