Can A Camouflage Expert Be Colorblind?
Updated: Dec 28, 2020
One morning, in the Sea Star Aquarium, Coburg, Germany, the staff found that the electrical system had shorted out. No electricity. No lights. No hum of machines. Nothing at all.
The electricians were called in. They fixed the problem or so they believed, because the next morning, to everyone's astonishment, the system had shorted out again. It shorted again the following day and the day after that, like clockwork.
The staff decided to spend the night at the aquarium to solve the mystery
Through the night, they kept watch and they saw... precisely nothing.
When morning came, they found the culprit.
Otto, the octopus.
The staff at the Sea Star Aquarium had taught Otto to aim and shoot water at visitors, but a cephalopod is a cephalopod. Otto being one of a kind, with an attitude and enough native intelligence, had decided shooting water at an electrical light was far more... rewarding. Can anyone blame him? It is more fun to create trouble than sit in a tank for the viewing pleasure of humans and if he can sit in a tank for us, why can't we fix the electrical system for him?
Just a thought, that. I'm not encouraging bad behavior in the cephalopods. Honest.
To keep Otto properly entertained, the staff gave him a chessboard, but after camouflaging for a while (if I understood the interview, he changed his colors to black and white to match the chessboard) he threw the chessboard out of the water. He didn't think chess was fun and I can't say I don't understand. I imagine Otto wanted to go back to shorting out more lights, but no one in the aquarium was in the mood to play.
That's mischief for you. And raw intelligence.
And if you don't think that's intelligence, how about an octopus that figured out how to get out of his tank in an aquarium, find a drain, and escape through it? Let us look at how good they are at being escape artists i.e., figuring out how to escape from a man-made tank.
Once again, a real-life example. Inky, the octopus, made a daring escape from his enclosure in the National Aquarium of New Zealand, by climbing out, finding a drain, and going out to sea. The news made headlines. See the video below (ABC news) about how Inky escaped. If you have seen the movie called "The Shawshank Redemption", you will get the humor here.
One more video about Inky's escape (sorry, wouldn't let me load it here but I pasted the link)
There are dozens of examples like these. Here, Otto has personality and he is playful. Inky is determined to get out of his enclosure to go home. They have intelligence and personality. This is by no means rare. Cephalopods are intelligent. They have big brains compared to the size of the their body and 2/3 of their brains are in their tentacles. The question is not if the octopuses are intelligent because the answer is an unequivocal yes!
The question is why?
Ed Yong has a great article on this in the Atlantic as has Carl Zimmer in the New York Times (see here). The gist of these two articles is that about 275 million years ago, the ancestors of the octopuses lost their hard, external shell which they used to have until that time. Now, an octopus suddenly found himself (or herself) able to hide under rocks and crevices, but with a disadvantage. Now they were more vulnerable to attacks from predators. So, to survive, the cephalopods found ways to disguise, camouflage, or solve problems using those nifty arms.
So, how do they stay safe? Octopuses have a list of tricks they can pull:
They arrange shells or stones around their den to barricade themselves, and therefore, protect themselves from sneaky predators. This is unusually smart for a creature, that is the ability to collect rocks and boulders, drag them to the mouth of their hideout, and then climb in and arrange them outside so as to block predators, much like we humans close our front doors, when go inside our houses. It is like closing a door.
They carry coconut shells with them so that if the need arises, they can hide inside. We have a story on this: "How to Impress a Coconut Octopus" and an associated video we intend to post soon. This is a remarkable case of an octopus carrying two half coconut shells, knowing these will close and fit on top of each other, to give him a safe haven.
They can get inside fishermen's crab-catching net, eat the crab, and get out in time.
And everything I've written above is not even the most amazing part of an octopus.
Here's the part that really got me when I first saw it.
Unless you have seen Roger Hanlon's video, which I first saw in David Gallo's 2007 Ted Talk, you've NO idea how what an octopus can do. None. So, do yourself a favor and watch this short 5 or 6 minutes Ted Talk by Gallo. You will not regret it, in fact, it could make your day.
Apart from the bioluminescence beauty of the deep, what is extraordinary are the examples of underwater magic. First up, how a male squid always shows his "gentle" side to a female. You may not believe it, but this is true. He does NOT show his aggressive side to the female he is trying to impress, even though he is feeling aggressive. How do we know? Just see it.
The next is how an octopus camouflages, which is a revelation.
So, here it is. Watch.
It's a Ted Talk and if you can't see the video, search for it in Google and it will pop right up.
Here is another video that show how many different kinds of creatures an octopus mimics.
So, there you have it. The ability to camouflage that is extraordinary.
Now here is the mystery.
Cephalopods' (squids, octopus, cuttlefish) eyes have only one kind of photoreceptor - which implies cephalopods can only see two colors - black and white. If the cephalopods can only see those two colors, that implies the cephalopods are colorblind. If that's true, the question becomes, how do these creatures excel in camouflaging? Against coral reefs, against sandy floors, algae, rocks, and even mimic other marine creatures or different forms and shapes?
So, what's going on?
How they camouflage makes it impossible to believe that the cephalopods are colorblind. It is not possible to blend in perfectly with your surroundings, some of which are very colorful indeed, especially near coral reefs, if you can't see the colors, but only see black and white.
Two answers to this mystery are (according to Carnegie Museum of Natural History) -
They see through their skin.
They make use of chromatic aberration.
According to Carnegie Museum of Natural History -
The chromatic aberration hypothesis proposes that instead of avoiding chromatic aberration, cephalopods enhance it using their peculiar off-axis pupil shapes. This enhancement allows them to detect color by monitoring image blurring as focus changes. Computer models show that this method of image detection is possible.
Such use of chromatic aberration could explain why cephalopods have such bizarre pupil shapes. The pupil in some octopuses is an elongate slit, and in cuttlefish, it is the shape of a W.
Clear as mud? I thought so.
I went searching other places (the best write-up I found on the octopus is here).
Here is one more explanation I could find from the above article in the Smithsonian -
Despite the complexity of their eyes, cephalopods are most likely colorblind. The ability to see color relies on specialized receptor cells. In animals and humans these cells are called cones, a distinction from the light sensitive cells called rods. Humans have three different types of cones: one that detects red wavelengths of light, one that detects blue, and one that detects green. In combination, these cones allow us to see a wide breadth of color hues. But cephalopods only have one type of photoreceptor cell, rendering it colorblind.
Or perhaps not! A recent study suggests that the strange shape of their pupils may allow some cephalopods to distinguish colors in a unique way. The unusual shape may act somewhat like a prism, scattering the various colors that make up white light into their individual wavelengths. Once the light has been divided, a cephalopod can then focus the individual colors onto its light-sensitive retina by a subtle change in the distance between the lens and retina. This method would take quite a bit of processing power compared to a multi-cone eye and can help explain why a cephalopod has such a large brain.
So in summary, is there any part of this creature that is NOT unusual?
Let us count the ways -
Doughnut-shaped brain.
Three hearts.
Blue blood (hemocyanin, i.e., copper-based molecule, instead of hemoglobin)
Extraordinary skin with difference mechanisms to aid in camouflage - chromatophores (different colored-pigments that can enlarge or contract) irridophores (reflect light and assist in coloring) and leucophores (white cells to provide the right background). On top of all that, muscles that provide texture - like lumps or humps.
Unusual eyes and pupils (so as to aid in chromatic aberration)
Enormously intelligent with "smart" arms.
Often shows a personality - can be moody, shy, playful, roguish, or sensitive.
Are you in awe yet?
Email us your comments at jrnsenn@gmail.com. We look forward to hearing from you.
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