Man’s next friend? Study finds squid and dog brains are similar

BRISBANE, Australia — If you’re on the lookout for a new animal companion, perhaps you should consider a squid. Before you balk at the notion of a pet squid by your side, consider the results of the first MRI-based mapping of the squid brain and its neural connections in 50 years.

Researchers from Queensland University say that these intelligent cephalopods have incredibly complex brains that are similar to those of dogs.

Reef squidq
UQ researchers have used modern technology to map the connections of the brain of the reef squid Sepioteuthis lessoniana. (Photo credit: Queensland Brain Institute, The University of Queensland)

“This the first time modern technology has been used to explore the brain of this amazing animal, and we proposed 145 new connections and pathways, more than 60 percent of which are linked to the vision and motor systems,” comments Dr. Wen-Sung Chung in a release.

This clearer picture of the squid brain has led the study’s authors to conclude that modern cephalopods, including octopus and cuttlefish besides squids, have deceptively intricate and numerous neural systems that rival that of a dog and far surpass mice or rats.

“For example, some cephalopods have more than 500 million neurons, compared to 200 million for a rat and 20,000 for a normal mollusk,” Dr. Chung explains.

This research will go a long way towards helping scientists explain how squids are able to so effortlessly and instantly camouflage themselves despite being colorblind. Other extremely intelligent abilities seen in cephalopods include counting, recognizing patterns, solving problems, and communicating with one another using signals.

“We can see that a lot of neural circuits are dedicated to camouflage and visual communication. Giving the squid a unique ability to evade predators, hunt and conspecific communicate with dynamic color changes,” Dr. Chung comments.

These findings also lend credence to convergent evolution theories regarding cephalopod nervous systems. Convergent evolution is the idea that otherwise unrelated organisms will evolve the same traits or skills due to living in similar environments or facing the same problems. Since the results illustrate similarities between cephalopod nervous systems and those of vertebrates, like dogs or even humans, it’s plausible to theorize that the two nervous systems evolved in a similar manner.

With these results in mind, the study’s authors say they are now able to make predictions regarding the cephalopod nervous system at the behavioral level based off of the already well known and studied vertebrate nervous system.

“For example, this study proposes several new networks of neurons in charge of visually-guided behaviors such as locomotion and countershading camouflage – when squid display different colors on the top and bottom of their bodies to blend into the background whether they are being viewed from above or below,” Dr. Chung explains.

The research team is still hard at work, and are now currently trying to understand why different types of cephalopods have evolved varying subsections in their brains.

The study is published in iScience.

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