Veined octopus (Amphioctopus marginatus) shell carrying

I almost drowned laughing when I saw this the first time - Julian Finn

It’s difficult for us to imagine alien life without adding in elements that reflect our own bodies. The classic grey aliens of film and UFO-sighting fame tend to have two legs, two arms, one head, and recognisable eyes and mouth. They have elbows and knees, and often have a thumb and fingers, even if there are minor variants (E.T. had only four digits on each hand, while the Alien Queen has six—how mysterious!).

Yet we share the earth with creatures whose bodies radically surpass these limited ideas. Often they are relatively small, like insects and spiders, so that their behaviour passes by beneath our notice. Or they may live in the deep ocean, where few people and even fewer cameras have ever been.

However, at the intersection of the lines for ‘alien body plan’ and ‘beneath the ocean waves’ lies an animal with which we are all familiar, the octopus. And the more time we spend with octopuses, the more we have grown to appreciate that while they strongly differ from us in almost every physical aspect, they share the very trait that we search for in alien life: intelligence.

The shell game

Between 1999 and 2008, Julian Finn (Senior Curator of Marine Invertebrates at Museums Victoria) and his colleague Mark Norman spent over 500 hours diving the warm coastal waters off Northern Sulawesi and Bali, Indonesia. An expert on cephalopods—soft-bodied marine creatures including squids, cuttlefishes, octopuses and the shelled nautiluses—Finn is also a seasoned and skilled photographer of marine life.

Still, he wasn’t prepared for the day a veined octopus (Amphioctopus marginatus) simply picked up a coconut shell and walked off with it.

Veined octopuses live primarily on the shallow sea floor, in and on the soft sediments. They are able to swim, but are also known to walk across the sandy bottom using two or more or their eight legs. What Finn and his co-authors reported in a 2009 paper in Current Biology, however, went beyond this behaviour.

Octopuses were seen carrying either one or two coconut shells up to 20m, holding them empty-side up beneath their bodies and surrounded by their legs. This position is unnatural for the animals, which means that they need to hold their legs quite stiff as they walk with the shells. The resulting gait was termed ‘stilt walking’ by the scientists.

The obvious question is why? And the answer is protection—once stationary again, the octopus can hide under a single upturned shell, or even enclose itself in two empty coconut halves. Its soft-body is encased in armour, a step up from simply burying itself in the sand and mud (which this species also does).

The veined octopus lives in the waters north of Australia up to Japan, and around the Indian Ocean rim. It isn’t known, though, whether this behaviour occurs across the species range, or only in a few groups.

Both the carrying behaviour and defensive tool-use are shown in this video from the paper’s authors:

Understanding aliens

The notion of intelligent molluscs hasn’t entirely escaped popular culture. The 2016 science fiction film Arrival (based on a short story by Ted Chiang) gave us floating, somewhat soft-bodied, tentacled heptapods that had their own language, writing system and conception of time. One key difference—the seven arms of the heptapod vs the eight of the octopus—is reflected in their name.

We weren’t shown the internal anatomy of a heptapod, but the octopus is strange enough without sci-fi elaboration. The octopus oesophagus (the tube connecting the mouth and stomach) goes straight through the centre of their brain, which is likely why they also have a beak and toothed tongue—they really need to break down their food before swallowing.

Their blood uses haemocyanin, a blue-green copper-based pigment, to carry oxygen, giving their blood the same colour. They use three hearts to push that blood around, to ensure sufficient oxygen as they go about their carnivorous lifestyle. Their arms have their own sensitive, sensory abilities, attached to a body that can shrink, flex and change colour as needed. And some species can detach an arm as a decoy, regrowing another perfectly healthy one over the following months.

With all these stark differences, and the fact that water-dwelling life is already fundamentally alien to us air-breathing, land-locked humans, is it actually even relevant to ask whether we have comparable intelligence? Any answer might presuppose that we knew something of what it’s like to be an octopus, which we don’t. As philosopher and octopus researcher Peter Godfrey-Smith concluded:

When I try to imagine this, I find myself in a rather hallucinogenic place.

Nevertheless, it’s easy to suppose that the octopus scurrying away, with its mobile home tucked underneath, is planning for its upcoming shelter. That would imply a degree of foresight—tool-use not only in the instant but as a strategic future investment.

A counter-argument would suggest that perhaps the animal has simply learned from prior experience that having a shell with it leads to greater protection from predators. However, that reductive approach would need to also explain away the fact that octopuses are master problem solvers and learners, responding to stimuli that humans don’t regularly encounter (e.g., electrical, water density, or light-based signals).

In this kind of debate, your conclusion is likely to depend heavily on what you already believe about other intelligences. Ultimately, we learn little from to trying to fit an octopus into a neat basket that might equate its abilities or sensations to a human’s. If we know one thing for sure, it’s that you can’t keep an octopus in a basket.

Further reading. For more on what it’s like to watch, study and maybe be an octopus, see Peter Godfrey-Smith’s excellent 2017 book Other Minds: The Octopus and the Evolution of Intelligent Life. And of course, you should read everything you can find by Ted Chiang.

Sources: Finn, J. et al. (2009) Defensive tool use in a coconut-carrying octopus. Current Biology 19: R1069-R1070 || Jereb, P. et al. (eds) (2014) Cephalopods of the world. An annotated and illustrated catalogue of cephalopod species known to date. Volume 3. Octopods and Vampire Squids. FAO Species Catalogue for Fishery Purposes. No. 4, Vol. 3. Rome, FAO. || BBC online news report (2009) http://news.bbc.co.uk/1/hi/sci/tech/8408233.stm [accessed November 2020] || Godfrey-Smith, P. (2019) Octopus experience. Animal Sentience 2019.270.

Main image credit: Sam Sloss https://www.theguardian.com/environment/gallery/2020/dec/01/wildlife-photographer-of-year-2020-peoples-choice-in-pictures || Second image credit: Finn et al. (2009) Current Biology, Fig. 1 || Third image credit: Nick Robertson-Brown https://royalsociety.org/journals/publishing-activities/photo-competition/2016-winners-runners-up/behaviour/