Everything You Always Wanted to Know About the Octopus

Kathleen Harmon Courage’s 2013 book, Octopus!, subtitled The Most Mysterious Creature in the Sea, is no relation to the 2025 documentary of the same name. It touches on some of the same themes, but it goes in a somewhat different direction. As a work of prose nonfiction, it can delve deeper into the facts and the science, and it does exactly that. It’s extensively researched and compulsively readable.

Courage begins with an expedition to one of the hubs of octopus fishing in the world, Vigo in Galicia, Spain. She calls it “the epicenter of octopuses.” It’s not only a major fishery in its own right but also a major processing center for octopus fisheries elsewhere—and a center for the scientific study of cephalopods. There is, she makes sure to tell us (with photo), a statue of Jules Verne there, though the cephalopods in Twenty Thousand Leagues Under the Seas are squid.

She focuses on the octopus as food for humans, in its historical context and as it’s happening around about the year 2012. We’re treated to a recipe for the local delicacy, Pulpo a Feira, a festival dish of octopus, potatoes, paprika, and salt. It’s delicious, she says.

No qualms here about eating a sentient creature. We’ll see more recipes and more discussion of the culinary uses of the octopus as she travels around the coasts of Europe and the Americas, with references to Japanese and Korean specialties. She’s particularly fascinated by Korean-style octopus, Sannakji, aka “live” octopus, as prepared by Sik Gaek restaurant in New York. It’s an illustration of a point, that the octopus has a notable amount of brain power in each of its arms as well as in its main brain.

Sannakji consists of freshly killed octopus arms cut up a la sashimi, on lettuce with sliced raw garlic, green onions, jalapenos, and a couple of dipping sauces. Eating it involves wrestling with the actively wiggling segments and the very sticky suckers. Again, she says, it’s delicious. She obsesses over it for days after.

She is in fact obsessed with the octopus in all of its manifestations. She hunts it, eats it, talks to people who study it both for its own sake, as biologists, and for its uses to the military and to the science of robotics. The octopus for her is more than a scientific curiosity. She’s particularly interested in what it can do for humans.

Humans have a tendency to make everything about them. We see it in the documentary, too. The marine biologist gets an octopus tattoo and makes an octopus quilt. The writer sees in the female octopus’ breeding cycle a reflection of their relationship with their own mother.

Courage wants to learn everything she can about this fascinating and mysterious creature. Mysterious for many reasons. Its weird anatomy and physiology by human standards. Its short life and, in human terms, tragic reproductive cycle. And above all, the difficulty of studying it.

It’s not just that an animal with blue blood, three hearts, eight semi-autonomous arms lined with suckers that can each act individually and smell and taste, a superpower-level gift of disguise, and no apparent social life or parental nurture, is pretty much the opposite of everything a human is. We can’t truly imagine how it lives in its world or how it thinks. We also face serious challenges in getting it to cooperate.

First we have to find it, and then we have to identify that we find. That means mounting lengthy and expensive expeditions to the oceans of the world. Once we get there, we have to track down an animal that can disguise itself as anything from a rock to a sea snake. That hides in spaces inaccessible to humans, though we might find evidence of it in the “garden” of its cast-off prey. That may look completely different in its larval form, and that may be so sexually dimorphic that, as with the blanket octopus, the female is huge and blanket-like and the male is a tiny little nubbin of a thing that doesn’t even look like the same species.

Once we find it, we have to keep it. An octopus can not only ooze through minuscule gaps in any trap we may build, its arms are strong enough to lift a locked lid or pull the trap apart. (Though that being said, Galician fishermen catch octopuses in baited creels that rely on the animal’s tropism toward dark enclosed spaces. Once they’re in, as long as they have something to eat, they’re not interested in leaving—no need to block their exit.) It can easily escape an aquarium and either go hunting in another nearby or find its way outside. This often is fatal for the octopus, since they can’t survive out of water for very long. But that doesn’t stop them from trying.

Once that obstacle has been overcome, we still have to deal with the fact that the octopus is a fantastically uncooperative research subject. Anything you put on it, it can and will pull off. It’s extremely difficult to immobilize without killing it. Everything is wiggly and wriggly and at the same time, as far as we can tell, insatiably curious. It wants to check you out. And pull you apart. And eat you.

It’s also very difficult to breed in captivity. You can get a male and a female together and she may produce eggs, but once those eggs hatch, they need far more space than a lab or even a commercial farming operation can offer. The hatchlings need live food, which will as likely be each other as whatever you try to feed them, and they grow at a phenomenal rate. The only really effective way to obtain them is to capture them in the wild. Which circles back around to the problem of how to find and keep them (either for research or for eating).

It also presents a problem for taxonomy—for identifying and studying the many species of octopus. Not only the difficulty of finding students willing or able to devote time to classifying the hundreds of known species, but also the nature of the animal itself.

Big-time understatement there.

Still, in Courage’s view, octopuses are worth it for what they can do for us. She lists some of the options. Engineering and robotics—a whole new concept of the robot, soft rather than hard, infinitely flexible, with semi-autonomous limbs. Pharmacology, especially the composition of its venom and its possible use in painkillers. Neurochemistry. Design and control of an artificial brain. The art and science of disguise, from color-changing fabrics to cloaking devices. Explorations of cognition, the nature of consciousness, the range of perception in an animal that lives in a truly alien environment by human standards.

We may never truly or completely understand the octopus. And that’s what makes it so fascinating. She describes it at both the beginning and the end of the book, in the words of filmmaker Jean Painlevé, as “a joyous confusion of the mysterious, the unknown, and the miraculous.”