Wondered into being by: God, evolution, whatever makes the weather (circle at least one)
Wonderspan: 5 min
While hunting for fish on the coast of Mexico, the traveller Craig Childs spotted an unusual spot of colour on the seabed. 'It was pulsing,' he wrote, 'an unaccountable bit of brilliance, and it had no apparent form other than light itself. … It looked like a floating prism no more than a few inches long.’ [from Animal Dialogues]
When he lifted the creature in his cupped hands for a more thorough wondering-at, he could see tiny organs contracting and relaxing beneath the translucent skin of its entirely boneless body. And, most intriguing of all, its surface ‘pulsed gently’ with shimmering colour. What Craig Childs had found was one of the smaller species of squid
Some of the extraordinary characteristics of squid and their cephalopod cousins are made possible by its quirky anatomy, particularly its brain. The nervous system of a cephalopod is highly distributed, with two thirds of its neurons outside its central brain organ. Its brain is, in effect, stretched right out to its skin, where it can electrochemically and instantaneously transform millions of iridescently pigmented openings to create complex patterns of colour. A squid or octopus can look at its surroundings and camouflage itself in just a few seconds. It can also use the colours to send signals. In some species of squid, males can sidle up to females and use one half of their bodies to put on a come-hither light show while displaying 'clear off' to a rival suitor on its other side.
In her Orion article, 'Deep Intellect: Inside the Mind of the Octopus', Sy Montgomery meets an octopus in an aquarium. She explains that the larger species of octopus, if they’re feeling friendly (and they do have moods), will want to meet you. They do this by wrapping their tentacles gently around your arms, so as to taste and feel you at the same time. They will turn their head towards you -- they know exactly where your eyes are -- and look right at you. Come back the following week and the octopus will remember whether or not it liked you.
This is more than a spooky likeness of intelligence -- it is the real thing. Here's an octopus learning how to open a jar, for example. In another experiment, researchers hid a crab in the middle of three nested, perspex boxes, each with a liftable lid fitted with a different kind of complex latch. They then popped the lot into an aquarium and watched an octopus feel each latch with its tentacles and learn how to open it. Octopuses will play, too. Sy Montgomery cites a research paper which found that some individuals would use their propulsion jet to squirt a plastic bottle around their tank, apparently just for something to do. This makes octopus intelligence comparable to that of the few other playful animals, such as crows, dogs and chimpanzees. Another weirdness is the creature's adaptability -- if an octopus escapes from a tank it will run away to find somewhere to hide. Yes, run on eight legs across the floor, even if that's its first experience on dry land.
To Sy Montgomery, an octopus is too clever to be an ‘it’, but must be a ‘he’ or a ‘she’:
‘No sci-fi alien is so startlingly strange. Here is someone who, even if she grows to one hundred pounds and stretches more than eight feet long, could still squeeze her boneless body through an opening the size of an orange; an animal whose eight arms are covered with thousands of suckers that taste as well as feel; a mollusk with a beak like a parrot and venom like a snake and a tongue covered with teeth; a creature who can shape-shift, change color, and squirt ink.’The larger squid show similar intelligence to octopuses, but the largest octopus comes nowhere near the size of the larger species of squid. The Humboldt squid can be as long as a human and given the chance would happily chew on one. They hunt in packs, first corralling fish into dense shoals then flashing a rapid red-and-white pattern just as they pounce. Their tentacles prickle with hundreds of cats-claw barbs for harpooning the flesh of their prey before dragging it to a hard ‘beak’ for crushing and ingesting.
But a Humboldt is far from the largest kind of squid. The famous giant squid of sea stories like 20,000 Leagues Under the Sea is real. It lives about 3km down, where it loves the extreme cold, the huge aquatic pressure and the pitch darkness. Amazingly, the first film of a live giant squid was only accomplished eight years ago; before then the only evidence they existed was occasional washed-up remains, giant squid beaks inside the stomachs of dead sperm whales and the tall tales of sailors. But in 2004, Japanese scientists lowered a lump of bait, a camera and a light into the depths on a 3000-metre cable and waited until, eventually, a giant squid wrapped its body around the meal.
Even this monster is not the largest of the squid. The most massive of all – as far as anyone knows – is the colossal squid, which is the world’s biggest invertebrate. A female could weigh up to a ton and measure 18 metres (59ft) in length, which is two thirds as high as a fully grown oak tree; its tentacles (so we might imagine) must be as thick as the branches. For me, the most exciting feature of the colossal squid is its eye -- the biggest and beadiest of any animal in the world at just over a foot in diameter. It’s all the better to see you with, my dear. Deep water squid also have the longest penises relative to body size of any mobile animal; all the better to... well, you know the rest.
You might think that, given the hostile conditions for life 3,000m beneath the sea’s surface, the deep-sea squid would cast lonely figures in the darkness. But the fauna at that depth is actually the richest of any ecosystem on Earth (including the rainforest). Yet, so marine biologists say, we know more about the moon than the deep sea, because even with the latest submersible technology it’s so hard to get down there and it’s completely dark. The giant and colossal squid are among possibly millions of deep-sea species.
The massive squids’ only significant predator (apart from each other) is the sperm whale. But rather than behave like sensible prey and try to swim away, a giant squid will pick a fight with an attacking whale by wrapping tentacles around its head. The whale responds by rising closer to the surface. Eventually, as the water gets a little warmer the squid can’t maintain its oxygen levels in its blood. When it gets sleepy and falls off the whale tucks in. Even so, the whale is likely to be a little worse for the encounter, too: older sperm whale heads are scarred all over by tentacle suckers and barbs, testifying graphically to the do-or-die tenacity of its prey. Presumably the squid's attacking technique sometimes works in its favour otherwise it would not have evolved.
But the most remarkable thing about the cephalopods is, perhaps, what so intrigued Craig Child's -- their incredible facility for changing colour and form. Let's finish with the octopus - here's a short film of the creature's camouflage and other defences. Pause the video at between 10 and 15 seconds in and see if you can spot him.
Extra...
Here's the rest of the two Ted.com talks by David Gallo, a very enthusiastic marine biologist talking about the spooky world of the deep sea.
- http://www.ted.com/talks/david_gallo_shows_underwater_astonishments.html
- http://www.ted.com/talks/david_gallo_on_life_in_the_deep_oceans.html
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