A team of scientists says a recent analysis suggests wild octopuses may possess the ability for targeted “throwing” – a trait that’s extremely rare in non-human animals.
Researchers first noticed the unique behavior while conducting a field study of wild octopuses in Jervis Bay, just off the southern coast of New South Wales, Australia. Dubbed “Octalantis,” Jervis Bay is one of the few known locations where octopuses build dens in the sandy seafloor and live in large numbers communally.
With vast numbers of octopuses living in a relatively small area, Jervis Bay offers the unique opportunity for a team of scientists, led by University of Sydney professor Dr. Peter Godfrey-Smith, to use underwater cameras to study how the typically solitary and asocial octopuses interact with each other.
While analyzing footage collected over roughly 8 years, Dr. Godfrey-Smith and his colleagues were surprised to discover that octopuses occasionally gathered silt, shells, or other nearby debris in their tentacles before angling their siphons to shoot a jet of water and launching the objects several body-lengths like a projectile.
“David Scheel [co-author of the study] was the first person to notice the behavior. He saw it in some cases that were borderline, but interesting,” Dr. Godfrey-Smith, told The Debrief in an email. “Octopuses would drop shells (not throw them) and the shells would hit others. So we started looking for things like this. Then, mostly on some unmanned cameras left at the site, we began to see the bigger’ throws.'”
Likening the act to “throwing,” researchers noted the octopuses would use the unusual technique in several ways, including discarding food waste and helping excavate their dens. Strikingly, scientists observed that octopuses would also appear to target and hit other octopuses with their throws.
In a preprint release of their research, scientists say the results of their analysis suggest, not only do octopuses have the previously unknown ability for launching objects, but these “throws” also appear to be relatively common and at times targeted.
If confirmed, this remarkable discovery would place octopuses within the extremely limited category of animals capable of using their body to launch projectiles, a trait dominated mainly by human beings and other primates.
BACKGROUND: How Rare is the Ability to Throw?
The ability to throw solid object projectiles is something most people likely take for granted. However, throwing a baseball or tossing a ball of paper in the trash can is a unique skill almost exclusively limited to human beings.
The title for the world’s most proficient non-human throwers goes to humanity’s distant ancestral cousins and primates, such as chimpanzees, gorillas, or orangutans.
Though indeed primates possess the ability to throw objects such as – rocks, sticks, and of course, the fan-favorite, feces -even the most proficient hurlers come nowhere close to having the ability to make the types of accurate and precise throws as humans.
In addition to primates, a handful of other animals are known to occasionally hurl projectiles. Elephants and some species of birds have been observed tossing objects about, and a recently published study suggests wild polar bears will infrequently throw rocks to aid in hunting walruses. Yet, in these few examples, the animal’s ability to launch a projectile is even less proficient than primates.
Because of the significant disparity in the throwing abilities of humans vs. non-humans, some biologists and anthropologists argue that throwing with precision or accuracy is a uniquely human trait.
In a 1975 field study, Harvard University professor, Dr. P.J. Darlington Jr., found that in throws by wild chimpanzees, only 11% of the time was an intended target actually hit. In those successful instances, Dr. P.J. Darlington noted this was only when a target was no further than 6.6 feet from the thrower.
“Other primates do throw sticks and stones, but only awkwardly…Compare this with human throwing. A skillful man has a good chance to break the skull of another man with one stone at 30m (100ft),” wrote Dr. Darlington Jr.
According to Dr. Godfrey-Smith, humans shouldn’t be too worried about being dethroned as the world’s best throwers by octopuses.
“I don’t know much about how precise the primate throwing is. I think some of it might be better targeted than our octos, but it’s hard to compare, as our guys are throwing a pile of stuff at once, not a single object, said Dr. Godfrey-Smith. “And the mechanics are different — jet propulsion applied to a collection of material held in the arms. I would not describe our octor throwing as very “precise.'”
Nevertheless, given that the field of non-human throwers is so slim, the mere fact that octopuses can hurl objects and may also be capable of engaging in targeted throwing is a significant discovery.
“It is hard to tell if an animal is using a projectile in a targeted way, but if this is happening in the octopuses, it is a very rare behavior, seen in very few animals (mostly chimps and other primates),” explained Dr. Godfrey-Smith.
ANALYSIS: Have Octopuses Entered the Non-Human Throwing Debate?
Octopuses can pull in water through cavities on their main body or mantle. Through a small funnel or siphon located at the front of their mantle, the octopus can eject this water to form a jet stream to aid in swimming and steering. The sea creatures can also use this siphon to push around or remove nearby materials.
In contrast, scientists say that the observed “throwing” by octopuses in Jervis Bay is distinctly different from this well-known “removing” behavior.
Unlike the indiscriminate “removing” behavior, researchers noted numerous occasions when octopuses would gather materials such as shells, silt, or algae in their tentacles and then purposefully position them so that the jet produced by their siphon could propel it outward like a missile. The scientists call these conspicuous acts “throws.”
“A clear case of a throw in our sense requires a water blast from the siphon that is directed at and simultaneous with release of material held in the arms, requiring that the siphon move into an unusual position below the arm web,” wrote researchers.
Researchers noticed several contexts in which octopuses seemed to engage in this unusual “throwing” behavior: Discarding the remains of a meal, assisting in excavating or cleaning its den, or in social settings when engaging with another octopus.
Of the observed “throws,” over half (53%) occurred during social settings, including “fights, matting attempts, approaches or reaches followed by an apparent reaction by another octopus, or instances where an octopus could interact with another while cleaning its den. An additional 32% of “throws” occurred during den-cleaning, 8% after eating, and 8% had no apparent context.
Perhaps most intriguing, in 33% of the throws in social and mixed-social contexts, researchers found that the material thrown ended up hitting another octopus. In these instances, scientists noticed several differences in the throwing behavior, suggesting these were targeted acts.
In their study’s pre-publication release, researchers highlighted several observations that may provide further circumstantial evidence that the hits on other octopuses were intentionally targeted acts.
Researchers found that octopuses tended to use more “high-vigor” throws when in social contexts. In other settings, such as den cleaning, the vast majority of throws were considered “low vigor.” High-vigor throws were found to more frequently hit apparent targets; however, researchers caveat that more intense throws have a longer and broader range, so this may not provide proof of deliberate targeting.
Octopuses were, however, noted to possibly have a preference for the type of materials thrown when in social settings. Based on observations, silt, rather than materials such as shells or algae, was used in 42% of the instances that other octopuses were hit.
Most of the time, octopuses used their frontal arms for throws. However, on occasion, an octopus was seen using the first two limbs on either the right or left side of their main body to perform what researchers accessed as “anomalous arm” throws. Octopuses were seemingly more accurate with this quirky throwing style, striking a potential target 43% of the time instead of 13% when launching material from the more common front two appendages.
Additionally, researchers found that octopuses displaying uniform body patterns, particularly dark patterns, tended to hit other octopuses significantly more than those with different body patterns.
At times, possible targets appeared to defend themselves, seemingly recognizing and preparing for the toss. In some cases, a target octopus would raise one of its arms up between itself and the thrower just before a throw.
In one instance, a female octopus threw material 10 times -scoring 5 hits – on a male in an adjacent den who had attempted to mate with her several times. During this sequence of events, the male octopus was seen ducking to avoid being hit just before 4 of the female’s throws.
Finally, on a few occasions, octopuses seemingly targeted throws at the researcher’s underwater camera. In one instance, an octopus threw material at the camera six times after it was accidentally placed too close to its den.
OUTCOME: What Throwing Octopuses Really Means.
Initial media reports seized on the mention of a female octopus throwing silt at a male trying to mate, implying the biggest takeaway from Dr. Godfrey-Smith and his colleagues’ research was that female octopuses fend off male harassers by throwing objects at them.
Speaking with The Debrief, Dr. Godfrey-Smith said these assumptions don’t necessarily reflect the researchers’ work and cautioned against assigning human behaviors, such as harassment, to the eight-limbed mollusks.
“Reports have made it sound as if it is always or usually females throwing at males who are “harassing” them. Some throws are by females who hit males — that is true. This does seem in some cases to be a response to a mating advance, but “harass” is misleading language here given its meaning in human social relations and its moral implications,” said Dr. Godfrey-Smith. “Also, many throws are by females who hit other females in nearby dens — in our 2015 data set, this was relatively common.”
During a mating attempt, researchers would often observe a male octopus recoil after being hit. However, shortly after, the male would try again to mate. In some cases, these later mating attempts were successful, potentially casting doubt on the idea that the initial throw was a purely defensive act.
Dr. Godfrey-Smith also stressed that though researchers classify the unusual behavior as “throws,” the act does not involve an octopus using its tentacles to launch objects in the same way force is delivered by the arm in a human throw.
Previous studies have found octopuses to be highly intelligent, with evidence suggesting the sea creatures can store both short-and long-term memories, and Veined octopuses have been recorded using coconut shells as tools to aid with the building of shelters.
In his 2016 book – Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness – the lead author of this recent study, Dr. Godfrey-Smith, proposed that based on their unique anatomy, cephalopods, like octopuses, have evolved with a distinctly different form of intelligence, and potentially consciousness, then vertebrates such as birds and humans.
That said, Dr. Godfrey-Smith suggests that though octopuses may ultimately be able to add targeted throwing to their already impressive bag of tricks, this alone does not speak to the sea creature’s intelligence.
“I don’t think it bears much on questions about general intelligence,” said Dr. Godfrey-Smith. “We don’t know whether this is a learned behavior, though it might be. It might be a behavior that does not have to be learned, but has not been seen before because it’s rare to see octopuses interacting with each other as much as they do at our site.”
As with interpreting any animal behaviors, assigning intention behind octopus throws is a challenging task.
Notwithstanding the “why,” indications are octopuses can be added to the shortlist of animals capable of regularly tossing projectiles. The focus now will be verifying the remarkable sea creatures are likewise able to purposefully target their throws.
“Our work has involved a long process of trying to put the evidence together that suggests some throws are targeted. We are not sure, but we think it is likely at this stage,” says Dr. Godfrey-Smith.