快猫短视频

IN THE late 1960s, Aradio Rodaniche was diving off the coast of Nicaragua when he made the discovery that has tantalised cephalopod biologists ever since.

Not only was the octopus he found startlingly beautiful 鈥� another biologist later said it was the most beautiful he had ever seen 鈥� but it was living in a den with others of its kind. That was unheard of. Octopuses are undoubtedly remarkable creatures: they can solve puzzles, use tools and even mimic other species. They have three hearts and multiple brains, with an intelligence rivalling that of famously smart animals such as crows and apes, and their visual communication abilities are mysterious and beguiling. But the octopus had always been considered a solitary beast.

The discovery of an apparently social species was so implausible that few believed it and Rodaniche鈥檚 story passed into legend. He published a , but hardly anyone had seen the animal and no one could confirm the report. It didn鈥檛 help that the octopus has never been officially described (see 鈥�Nameless wonder鈥�).

Gradually, the situation is changing. Work is emerging that confirms what Rodaniche originally suspected. The animal, referred to only as the larger Pacific striped octopus (LPSO), does seem to be a social species, and a couple of other types of octopus have now been discovered that also show social behaviour. Beyond the breathless prospect of octopus communities with hive minds even smarter than any of their members, these breakthroughs indicate it is time for us to reassess these fascinating creatures.

The LPSO is a small animal, with a striped body about 7 centimetres long and spotted arms that make it look like it is wearing a polka-dot dress. It lives at depths of up to 300 metres in the eastern Pacific Ocean, in regions with sandy and muddy floors.

Unlike most other octopuses, female LPSOs don鈥檛 die after laying their eggs. They also share dens with others of their species, sometimes in groups of up to 40. 鈥淟PSOs live about two years and females lay eggs over a period of a year,鈥� says Roy Caldwell at the University of California, Berkeley. 鈥淚 think the apparent social nature of this species has to do with the habitat in which they are found,鈥� he says. 鈥淒ens are hard to come by and may be clumped, leading to close interactions among individuals.鈥�

Caldwell and his team found that denning sites persevered for longer than the lifespan of an individual. This seems to be because, on the sandy and muddy sea floor that is typical of LPSO habitats, suitable spots are few and far between. The biologists don鈥檛 label them as such, but it is tempting to think of the persistent aggregations as octopus villages.

Christine Huffard at the Monterey Bay Aquarium Research Institute in California is one of the scientists who worked with Caldwell to confirm Rodaniche鈥檚 original observations. 鈥淭hey hold significant mystery,鈥� she says, picking out another behaviour unique to LPSOs: their habit of mating face to face (or more accurately, beak to beak) with their arms entangled. 鈥淭he LPSO mating system made us rethink what we consider possible for octopuses to do,鈥� she says. 鈥淢ales and females of this species interact in repeated, complex ways, further eroding the generalisation that all octopuses live purely solitary lives.鈥�

In most octopuses, sex takes place when males pass females a package of sperm called a spermatophore or insert it directly into them. Females in other octopus species are able to mate with multiple males at once, but by mating beak to beak, LPSO males can monopolise access to a female. The behaviour seems to help males guarantee that they will father the subsequent clutch of eggs.

鈥淪he can鈥檛 crawl around and feed while dragging the mating male in tow,鈥� says Huffard, as occurs in other species. 鈥淭his limits female feeding activity, but also limits her mobility and keeps her close to her den and the nearby male. It might limit her exposure to other males.鈥�

But what about the most celebrated aspect of octopus biology, intelligence? Does group living make LPSOs collectively smarter?

鈥淭here is no need to fear hyper-intelligent octopus communes plotting our downfall鈥�

We already know that octopuses process information in unusual ways, with their brains distributed through their bodies. Each arm effectively has its own mini-brain, as does the visual system. This allows them to multitask, so an arm can explore or manipulate a food item while the head gets on with . In the lab, the LPSO has been filmed creeping up on a shrimp and tapping it on its 鈥渟houlder鈥� to .

But octopus intelligence isn鈥檛 necessarily the same as ours. When they perform a complex task, it might not be that they are weighing up the problem and devising a strategy; they may just be following a simple rule that often results in a positive outcome. 鈥淲e don鈥檛 know whether their apparently complex behaviours are even underpinned by complex intelligence or whether they are using cognitive shortcuts to govern such behaviours,鈥� says Alex Schnell at the University of Cambridge. In other words, it could be all talk and no polka-dot trousers.

Octopuses of many kinds can, however, learn, which Jennifer Mather at the University of Lethbridge in Alberta, Canada, says indicates the presence of an organising mind. As for why they don鈥檛 show complex social behaviour, Mather points out I am being anthropocentric by even asking the question. 鈥淓very 鈥榳ay of life鈥� has its assets and liabilities,鈥� she says. 鈥淪ociality has its values, but it brings competition.鈥�

Even these most social of octopuses aren鈥檛 great at interacting with each other. They don鈥檛 tend to be good at recognising members of the opposite sex, for example. This is hardly surprising: without much generational overlap and a short lifespan, there hasn鈥檛 been much opportunity for evolution to work on social interaction.

All of which suggests we don鈥檛 need to fear hyper-intelligent octopus communes plotting the downfall of human civilisation. But there is enough mystery left in these creatures without hyping them as subaquatic aliens. The recent discovery of complex social behaviour in other species 鈥� as reported by Huffard for the 鈥� shows how much more there is to learn about the intelligence and behaviour of this remarkable group of animals.