Octopuses are the weirdly wonderful ocean animals who have blue blood, changeable colors and the ability to use tools. However, they’re probably most famous for having eight arms—which they can regrow—and bulbous heads. But even with all that, there’s so much more to these cryptic creatures.
What you may not know is that they have the most flexible appendages known in nature. In addition to being soft and strong, each of an octopus’s eight arms—and they are arms and not tentacles, as some label them—can bend, elongate, shorten and twist in many combinations to produce diverse movements.
An octopus has an excellent sense of touch. Most octopus species have suction cups on the bottom of each arm, and these suckers have receptors that enable the animal to taste what it is touching. Each arm seems to have a mind of its own, too; in fact, two-thirds of an octopus’s neurons are in its arms rather than its head. That means that an octopus can focus on exploring a cave for food with one arm while another tries to crack open a shellfish.
Octopuses are very intelligent; their brain-to-body ratio is the largest of any invertebrate and larger than many vertebrates. But there’s something else quite charming (if you ask me!) that we’ve just learned about them: they like to throw stuff at each other.
Throwing with every arm
Found in every ocean of the world and along every coast of the United States, octopuses spend much of their time in dens—small crevices and holes in corals and rocks. Some species live on the ocean floor, making their homes out of caves.
One spot just off the coast of eastern Australia is known as a gloomy octopus—scientific name Octopus tetricus—“city.” And it’s here that scientists have recently made a discovery: they witnessed the animals appearing to deliberately throw debris at one another.
Researchers at the University of Sydney used underwater video cameras to observe the behavior of gloomy octopuses in Jervis Bay in 2015 and 2016. After analyzing 24 hours of footage across several days, they were able to identify 102 instances of debris-throwing in a group of roughly 10 octopuses.
These marine mollusks gathered material, such as shells or silt, and released it while using a jet of water from their siphons—a siphon is a funnel-like hole on the side of an octopus’s mantle that can eject water at speed—to propel it between their arms, often “throwing” material several body lengths away. The mantle, located behind the octopus’s head, is a highly muscled structure that houses all the animal’s organs. To perform the throws, the octopuses had to move their siphons into unusual positions, indicating that this behavior is deliberate.
Both females and males were observed throwing, but 66 percent of the throws were performed by females. Around half of the throws occurred during or around the time of interactions with other octopuses, such as arm probes or mating attempts; and about 17 percent of the throws hit other octopuses.
Octopuses can change their skin coloration. Dark colors are generally associated with aggression, and the researchers found that dark-colored individuals tended to throw more forcefully and were more likely to hit another octopus. Those hit by thrown material often altered their behavior by ducking or raising their arms in the direction of the thrower.
Publishing their findings in the science journal PLOS ONE in November 2022, the researchers say that this is the first time that such throwing has been documented in octopuses. And although it’s difficult to determine the intent of octopuses propelling debris through the water, it seems that at least in some social contexts, octopuses are capable of targeted throws towards other individuals, an act that has only been seen previously in a few nonhuman animals.
You can watch the fascinating Jervis Bay, Australia, octopuses in the video below.
Loving with each heart
Octopuses have been having a moment of late. In 2020, the Netflix Original film My Octopus Teacher, directed by Pippa Ehrlich and James Reed, won the award for Best Documentary Feature at the 93rd Academy Awards. The movie depicts the year spent by filmmaker Craig Foster in which he forged a relationship with a wild common octopus in a South African kelp forest.
Foster meets a curious, young octopus and follows her around for nearly 12 months. The octopus plays with Foster and allows him into her world to see how she eats, lives and sleeps; and the two of them become close. Rotten Tomatoes, an American review-aggregation website for film and television, states that My Octopus Teacher is “a heartwarming look at the way a meaningful bond can transcend just about any barrier.”
I find that evaluation to be extremely apropos. Because in addition to nine brains—one central brain and the eight groups of nerve cells at the base of each arm that can control each arm independently, acting as smaller brains—an octopus has three hearts.
Here’s to finding your true places and natural habitats,