The underwater cameras pack a punch: the octopuses emerged from a messy bed of empty shells, arms unfurled like ribbons. Then suddenly a cloud of debris erupted from under her arms. Most of the time it was silt that billowed through the water like smoke. Sometimes it was mussels. Sometimes it hit another octopus.
The action took place dozens of times a day in the waters off the coast of Australia in 2015 and 2016. The contestants were somber octopuses, likely given their name for their pained-looking eyes. A casual observer might assume these funky-looking octopuses are battling it out with silt instead of snowballs, or engaging in playful fights. After all, we humans tend to humanize animals, especially when they exhibit behaviors that seem familiar to us. This tendency can be particularly alluring in the case of cephalopods—elusive, graceful-looking creatures known for their mysterious aura and remarkable intelligence, which have acquired an almost mystical status in the public imagination. But there may be a lot less than meets the (sad looking) eye in this particular series of underwater observations.
David Scheel, an ecologist at Alaska Pacific University, and his colleagues analyzed hours of the murky squid footage. Dusky octopuses, the team found in a study published today, quite deliberately tossing things around, sometimes directing the debris at other nearby octopuses. “It seems like there’s a target and they don’t throw a way; they throw at‘ Scheel said to me. Such throwing behavior, the researchers say, has never been observed in octopuses before.
Slingshot works like this: an octopus collects and holds debris with its arms, then expels water through its siphon, a funnel-shaped structure that octopuses use to propel themselves through water like an anatomical jetpack. The jet of water makes the debris fly. Half of the incidents recorded by Scheel’s team occurred when other squid were nearby. Squid whose skin temporarily darkened – a response linked to aggression – threw debris more strongly and were more likely to hit another animal. Some animals showed signs of what could be interpreted as targeting, releasing material from their sides rather than the front. And some octopuses in the line of fire seemed to react like any human: raising their arms towards the attacking octopus, or simply ducking.
Several octopus researchers who were not involved in the work question whether the behavior actually counts as tossing. The siphon action is similar to “squeezing your chest muscles and blowing air out through your nose and mouth,” Robyn Crook, an evolutionary biologist at San Francisco State University, told me. Although scientists have observed octopus passing and releasing material with their arms, they have not documented a concerted act of throwing, as most of us understand the process: grab something, rewind an arm, extend that arm outward, and finally release the object . “To me, a throw sounds like it should involve these types of moves in this type of sequence,” Crook said.
Siphon-directed pseudo-throwing actually happens all the time. Squids love to clean out their cave, especially after a large meal, and they use this part of their body to do it. Maybe they happened to meet another octopus; In the footage, only about 17 percent of the “throws” hit others in the area. “It seems like most of the time they just randomly remove things from their environment,” Crook said. What looks intentional to one observer may appear random to another. “Many animal behavior analysts would look at the same sequence of behavior and give a different interpretation,” Crook said.
Scheel and his team say the behavior is remarkable because it occurs in a social context — one octopus hitting another! However, Jennifer Mather, a cephalopod expert at the University of Lethbridge, cautions against describing the interactions observed between these octopuses as social behavior. Octopuses are solitary creatures, but we humans seem keen to believe that they can live together in harmony. When divers discovered underwater settlements of dusky octopuses in Australia, the popular press dubbed the sites “Octopolis” and “Octlantis”. But the animals were never attracted to each other, Mather told me. “This is a case of being drawn to a place to hide.” They simply took shelter in a shell-strewn spot in an otherwise empty, muddy expanse.
Although the filmed sinister octopuses tried to hit each other, their behavior may not have been strictly social. Scheel’s team also observed octopuses hurling debris at a nearby camera and some fish. Piero Amodio, a biologist who studies octopus behavior at the Anton Dohrn Zoological Station in Italy, believes that mussel sucking is likely “more widely used to create annoying or threatening stimuli,” octopus or not.
This uncertainty is not an octopus-specific problem. “It’s really hard to infer animal motivation,” Christian Nawroth, who studies goat behavior at the Research Institute for Livestock Biology in Germany, told me. That’s especially true if you’re observing them in a natural habitat rather than a controlled environment where you can adjust experimental conditions. Goats have their own secrets. They sneeze when they’re startled or frustrated, and “there’s actually nothing on how often goats exhibit this behavior, how often they use it, in what contexts they use it,” Nawroth said. Anecdotal reports suggest that some goats carry a branch on their horns and use it to scratch parts of their bodies. Maybe it’s actual tool use, or maybe “the branch somehow landed or got stuck between the horns and they’re using it to scratch themselves now just because they’ve found they can, and there’s no insight involved.” to actually use this tool,” Nawroth said. These are genuine mysteries of animal intelligence, but none of them seem to pique our interest in the same way as similar behaviors in squid.
Octopus researchers know their subjects are very popular. There is no shortage of popular science books or documentaries on octopus consciousness, intelligence and even souls, the accounts are awe-inspiring. (Scheel himself is writing a book subtitled The secrets of the octopus.) When we’re not depicting octopuses as cute stuffed animals, we’re asking them to predict the results of World Cup games (and think they’re good at it). “A lot of people find octopuses charismatic and interesting, and you seem to see an over-interpretation of behavior in cephalopods, where people tend to see extraordinary abilities where a more parsimonious explanation would probably suffice,” Crook said. Mather put it more simply: “Maybe it would be nice if squid weren’t sexy.”
Scheel said he and his colleagues will continue to look for answers in the gloomy octopus footage. The animals on the tape are long gone now; Like most squid, gloomies are thought to only live for a year or two, Scheel said. Researchers haven’t been monitoring the site recently, so they don’t know if others have accessed it. You don’t know if a new generation of sand-coated seashells are spraying around, maybe on purpose, but maybe not without paying attention to the inscrutable creatures on land who really, really want to figure out what’s on their minds.