One of the unexpected joys of having small children is having to adjust your mindset to the pace and contours of how they experience the world.
Unencumbered by the frameworks and presuppositions that we have spent a lifetime acquiring, they tend to approach things with an open and questioning attitude which, while often exhausting, can also be stimulating.
Some questions are easier to answer than others; my third favourite dinosaur is Baryonyx, but I don’t know enough about the underlying mythos of Paw Patrol to explain why a meteor would confer superpowers on a puppy. But sometimes the questions provoke that same sense of curiosity in me.
What do aliens look like? The simple answer is that I don’t know and, as far as I’m aware, neither does anyone else. In everyday life, that would be the end of the discussion. But when asked recently, it got me thinking about what our current knowledge would suggest.
When imagining extraterrestrial life, our minds often leap to little green men or science fiction monsters. But two very different animals are probably our best starting points: the crab and the octopus.
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Why crabs? Because evolution keeps turning up crab-like forms here on Earth. And octopuses? Because they represent a radically different kind of mind, one that could mirror alien consciousness. Understanding these two forms could help us refine our expectations of what alien life would be like.
Life on Earth often solves problems in similar ways, even when species are unrelated. Biologists call this convergent evolution: organisms independently evolve similar traits as adaptations to comparable environments or challenges.
Dolphins and sharks both developed sleek, streamlined shapes with fins even though their lineages are worlds (and millions of years) apart. Even complex organs can converge; eyes with lenses and retinas evolved independently in both humans and octopuses.
In fact, eyes of some form have evolved dozens of times in the animal kingdom. The same selective pressures often result in the same innovations, and so evolution tends to reuse winning designs.
One of the most striking cases of convergent evolution is carcinisation, the tendency for evolution to repeatedly produce crab-like creatures. Over the past 200 million or so years, the crab form has evolved at least five separate times. In other words, crabs have evolved not from one single crabby ancestor, but via several independent lineages of crustaceans that all converged on the same general body plan. Evolution, it seems, has a bit of a thing for crabs.
Why do crabs keep appearing? The crab shape confers serious advantages in certain environments. In essence, the crab design is like a living tank: well-armoured, good at wedging into hiding spots, and armed with pincers for defence or feeding. Evolution hit upon this winning formula multiple times because, in similar niches, a crab form simply works.
Octopuses show us how intelligence can arise under very different biological conditions to ours
While crabs are a potential physical template for alien life, octopuses offer a blueprint for minds that evolved down a separate path from ours. Split from our lineage more than 500 million years ago, they developed remarkable intelligence, but in a body plan that decentralises thought.
Only a third of an octopus’s 500 million neurons sit in the head, the rest in its eight arms. Each limb hosts its own motor-sensor circuits, able to taste, touch and execute complex manoeuvres without instruction from the central brain.
That arrangement challenges how we think about subjective experience. Where humans feel a unified self that can direct obedient limbs, an octopus may inhabit a chorus of semi-autonomous actors that occasionally sync. Does it merge those voices into one consciousness, and if so, how? The question fascinates biologists and cognitive scientists because it stretches our picture of what a mind can be.
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We tend to imagine the singular self as the default, not least because, by definition, it’s difficult for us to imagine otherwise. A species with a networked nervous system could act and plan with a fluid or collective identity. This isn’t necessarily alien: ants and bees exhibit colony-level problem-solving.
But octopuses show us how intelligence can arise under very different biological conditions to ours. They have no skeleton, live only a few years, and are generally solitary. Yet they exhibit curiosity, playfulness, and problem-solving. They can navigate mazes, open jars to get food, and have even been observed collecting objects to build fortresses.
Whatever form aliens take, they’ll probably seem strange, at least until we realise how strange we must look in return. Especially if we have to explain Paw Patrol.
Stuart Mathieson is research manager with InterTradeIreland
