The Soul of an Octopus: A Surprising Exploration into the Wonder of Consciousness

by Sy Montgomery

MIT researchers now know not only that rats dream, but what they dream about. Neurons in the brain fire in distinctive patterns while a rat in a maze performs particular tasks. The researchers repeatedly saw the exact same patterns reproduced while the rats slept—so clearly that they could tell what point in the maze the rat was dreaming about, and whether the animal was running or walking in the dream.

A 2012 study showed that if fruit flies’ sleep is interrupted repeatedly, they have trouble flying the next day—just as a person would have trouble concentrating after a sleepless night.

Hatching from an egg the size of a grain of rice weighing three-tenths of a gram, a baby giant Pacific octopus doubles its weight every eight days until it reaches about 44 pounds, then doubles its weight every four months until maturity.

Octopuses and their relatives put chameleons to shame. Most animals gifted with the ability to camouflage can assume only a tiny handful of fixed patterns. The cephalopods have a command of thirty to fifty different patterns per individual animal. They can change color, pattern, and texture in seven tenths of a second. On a Pacific coral reef, a researcher once counted an octopus changing 177 times in a single hour.

An octopus brain, depending on the species and how you count them, has as many as 50 to 75 different lobes. And most of an octopus’s neurons aren’t even in the brain but are in the arms. These may be adaptations for the sort of extreme multitasking an octopus must undertake: to coordinate all those arms; to change color and shape; to learn, think, decide, and remember—while at the same time processing the flood of taste and touch information pouring in from every inch of skin, as well as making sense of the cacophony of visual images offered by the well-developed, almost humanlike eyes.

There is another important difference as well. Human eyes have three visual pigments, allowing us to see color. Octopuses have only one—which would make these masters of camouflage, commanding a glittering rainbow of colors, technically color-blind. How, then, does the octopus decide what colors to turn? New evidence suggests cephalopods might be able to see with their skin.

If the arm has suckers all the way to the tip, you have a female. If not, the appendage is referred to as the hectocotylized arm, and the animal is male. The reason it takes a while to tell is that octopuses won’t always let you examine this arm, especially the males. They tend to keep the tip—the ligula—balled up and protected, and for good reason: This is the specialized organ for placing the spermatophore inside the female. (But he doesn’t put it between her “legs,” or arms, because that’s where her beak is. He puts it in her mantle opening—or, as Aristotle explained it, he “has a sort of penis on one of his tentacles . . . which it admits into the nostril of a female.”)

Each sleeps in its own private mucous cocoon, a slimy sleeping bag secreted from the mouth, to conceal its scent from predators. Parrot fish are sequential hermaphrodites: All are born female, and later transform themselves to males.