Octopus Play and Squid Eyeballs—And What They Can Teach Us About Brains

For cannibals, octopuses seem to be surprisingly fun loving. Some have been observed using their funnels to repeatedly blow objects around in their tanks.

Join Our Community of Science Lovers!

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


For cannibals, octopuses seem to be surprisingly fun loving.

Some have been observed using their funnels to repeatedly blow objects around in their tanks. Others, such as one common octopus named Dorian, have spent a countless minutes passing Lego blocks around among their many arms or towing them back and forth across the surface of the tank.

After careful study and deliberation, researchers decided there was really no good reason—food, safety or reproduction—for octopuses to be doing these things. The octopuses were instead doing something rather surprising.


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


They were playing.

Such complex behavior might seem impressive for a mere mollusk. But, as we are learning, the octopus nervous system is a masterful—if still partially mysterious—solution to life in the fast-moving ocean. Especially when you don't have a shell or a carapace to hide inside of (clams and lobsters, I'm looking at you).

These investigations and many others are described in the new book Cephalopod Cognition (Cambridge University Press, edited by Anne-Sophie Darmaillacq, Ludovic Dickel and Jennifer Mather). In it nearly two dozen of the world's leading experts on octopuses, squid, cuttlefish and nautiluses come together to share fascinating tales of surprising behavior—and what we are learning about the detailed physiology behind it.

After swimming with the octopuses—literally, although mostly figuratively—for more than four years now, as a non-expert, I feel relatively well versed in their oddities. But this book has opened my humble human eyes (blemished, unlike those of an octopus, with a blind spot) to many new astounding facts—and exciting avenues for future study.

Not to mention many questions I had never before pondered. Such as: Why do squid eyeballs get bigger and then smaller with ocean depth?

If you're the slightest bit intrigued by these weird invertebrates, you can hardly do better than to be in the capable hands of this volume's contributors.

And you might just learn something about the evolution of our own brains in the process.

Learn more about the inner world of surprisingly smart cephalopods in Octopus! The Most Mysterious Creature In the Sea, which is out now in hardcover and available for pre-order in paperback (ships November 25th).

Illustration courtesy of Ivan Phillipsen

Katherine Harmon Courage is an independent science journalist and contributing editor for Scientific American. She is author of Octopus! The Most Mysterious Creature in the Sea (Current, 2013) and Cultured: How Ancient Foods Feed Our Microbiome (Avery, 2019).

More by Katherine Harmon Courage

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe