How the heck do color-blind cephalopods — octopus, squid and others — achieve such a good color match when they camouflage? (in short: amazing, distributed brains). And what does it take to study these elusive animals in the wild? (a whole lot of patience). Marine scientist Roger Hanlon dives deeper into his research.
Have you ever stumbled upon a subject so intriguing that it fired your imagination and made your brain clamor for more, more, more? That’s how we felt about the talk from marine scientist Roger Hanlon where he revealed the incredible discoveries that researchers like him are making about octopus, squid and other cephalopods. TED’s Mary Halton sat down with him after he spoke in Vancouver in April to learn exactly how he studies them (must-haves: patience and laser focus), some of their amazing attributes, and just how much we still need to understand about them.
TED: Your talk is all about the amazing intelligence of the octopus, squid and other cephalopods. Can you put it into context for us? Where does its intelligence sit, compared to other animals — like dolphins or corvids — that we think of as being particularly smart?
Roger Hanlon: That’s an impossible question to answer [and] I’m worried about the term “intelligence.” I think the key thing is animals that are so well adapted to their specific, unusual environments. If you take that into [account], then I can easily see it’s equivalent to a corvid. I don’t think it’s quite as good as a fox, but it’s up in that category. (Editor’s note: The corvid family of birds includes crows, ravens and rooks, and it’s thought to be among the most intelligent birds studied.)
Some of the demonstrated behaviors of octopus — such as its episodic-like memory, its spatial memory — are thought to be really high-level things. So they’re comparable to fishes and birds, and, in some cases or elements, to higher vertebrates and even to mammals. Everyone thinks cats and dogs are clever — and they are in different ways — but cephalopods can do some things that are comparable to those animals.
The octopus, cuttlefish, squid — they’re just such oddballs. People just can’t imagine there’s a high level of intelligence in something that weird, but there is!
TED: Why do you think most people don’t know this about octopus? Is it because they’re not in our daily environment?
Hanlon: There are only a few charismatic species in the ocean that people pay attention to, things like dolphins and sharks. The octopus and cuttlefish and squid — they’re just such oddballs. I think they’re getting enough attention now from the media that people are beginning to see a little more, but they’re just such a strange animal. People just can’t imagine that there’s a high level of intelligence in something that weird, but there is!
TED: You point out in your talk that there there are some things we don’t understand about them because we’re not smart enough to know what questions to ask. Can you explain what you mean?
Hanlon: There are some young researchers coming into the field who are asking those very tough questions [about them]: Are they capable of play? Do they have high-level cognition? Do they do dreaming and memory consolidation the way we do? The spatial memory, for example, of an octopus is extraordinarily good. We can’t figure out how it works, and it’s something of interest to a lot of folks who study learning and memory.
The neuroscience community is starting to accept the idea that many animals have higher level cognitive capabilities, and we’ve not paid attention to them. We’re opening up our own brains and thinking, “OK, let’s look at this and see what they can do.” But it’s hard to ask the right question when you’re dealing with a cephalopod head foot. I mean, if our head was on our feet, we wouldn’t look like this! It’s alien right away, at least in appearance. (Editor’s note: The term cephalopod means “head foot” in Greek, referring to the way that a cephalopod’s head connects to its multiple arms.)
Octopuses observed by Hanlon made an average of 177 camouflage decisions in a single hour.
TED: You’ve said that only a small number of divers have observed them. How challenging is it to do fieldwork? Are there a lot of days when you don’t see anything? Is it a matter of perseverance or knowing where to look?
Hanlon: It’s all of the above. I’ve been diving for 45 years, I’ve done thousands of dives, and, early on in my career, I wasted a lot of time learning how not to do it. We eventually got smarter, took volunteer groups out, and found where their dens are. Then we would station ourselves on the den early in the day and watch from a distance until the animal came out for its normal foraging period. We’d let the octopus see the divers, spend 10 minutes habituating to them, realize they’re not a negative stimulus, they’d start their normal foraging, and we began getting real data. We would use successive dive teams with a lot of patience and a lot of wasted time underwater.
How we operate now is we do something called “focal animal sampling.” You have to be extremely disciplined to focus on one animal or one pair, and stick with it the whole time, no matter what happens. There might be something really great going on in your left peripheral eye vision, but you don’t go over and look at it because you want to quantify what this animal is doing. That’s when you get the rare behaviors, but it takes forever. Every natural history cinematographer knows this. I’m just doing it underwater, where you have a lot less time.
TED: In your talk, you speak about finding that an octopus can make as many as 100 camouflage decisions in two hours. How did you learn this? Did you follow one animal for two hours straight?
Hanlon: Yes, and we did it several times over a week-long period, so you could count the number of times it was changing. It would be here, camouflage, do a stealthy move over to here, and when it stops over here, it’s a totally different background, and they have to assess that background and modify the camouflage. They’re doing that over two hours covering a couple of 100 meters. Actually, the mean was 177 times per hour for the octopuses that we did [track].
Octopus’s camouflage reaction times are faster than any other animals’, occurring in one-fifth of a second.
TED: How do their camouflage reaction times differ from other animals, like chameleons?
Hanlon: Oh, the fastest ever. We’re talking as fast as 200 milliseconds — that’s one fifth of one second, the fastest human eye blink you can do.
TED: Can all cephalopods camouflage so quickly, or is just the octopus?
Hanlon: Almost all of them can — squid, cuttlefish, octopus. It’s because you have neuron cell bodies in the brain that go all the way out to the periphery and hook up directly to a chromatophore organ [which is what creates the color change]. So it’s the fastest wiring diagram you can create in biology; you don’t have any intermediary stops. I’m interested in rapid adaptive coloration, and that means it’s neurally controlled. There’s a lot of animal coloration that is slower and hormonally controlled. [That’s because] hormones have to take time to go into the blood, distribute, get back into the tissue, and do something. The cephalopods don’t do that at all. It’s like electric skin. It really is!
TED: That’s amazing. You mention it’s quite recently that scientists have discovered cephalopods have opsins, or light-sensitive proteins, in their skin. Is it true opsins are usually present only in the eyes of other organisms?
Hanlon: All animals have opsin molecules in their eyes; those are the molecules that absorb a photon of light and help with other molecules to turn it into a neural signal, which becomes vision. We knew what the gene was for the opsins in the retina of a cuttlefish, then we searched for that gene in the skin and found it. That was astounding. There are lots of opsins in the skin of many animals — think of frogs in particular — but [in cuttlefish] the exact same opsin that is in their retina is in their skin! That was the first that’s ever been seen.
TED: Is having these opsins in their skin somehow connected to their lightning-fast distributed decision making? Is all their skin sensing what’s around them?
Everyone thinks cats and dogs are clever — and they are in different ways — but cephalopods can do some things that are comparable to those animals.
Hanlon: That’s what we think, but we have not an ounce of data to prove that. It’s one of these really, really hard biology questions, because when you look in the skin you can detect that there are molecules but the molecules are not aggregated into a cell, tissue, organ, [or] anything that you can find. It’s just molecules in the skin.
We have no idea how the cephalopods might take that information and do something with it, because it’s only a molecule. So the idea is there, and I would even say they could probably do it — “probably” in heavy quotes — but no data. It’s really intriguing.
The question we’re trying to get at is: How do cephalopods achieve color-blind camouflage? Their predators have great color vision, and the cephalopods’ color match to their background seems to be quite good. But cephalopods are colorblind, so it’s really amazing that they can get the color so close without having color capability in the eye. That’s why we looked at the skin. We published a short paper in Biology Letters, and that got us a five-year grant and we really studied it. Now we still don’t know. Welcome to science!
TED: What does the world look like through the eyes of an octopus? Is it shades of gray or what?
Hanlon: Oh, this is a great question. Well, they do not have a round pupil. Cuttlefish, for example, have a ‘w’ shaped pupil or two slants. They have very good contrast vision. They can see polarized light — which humans are totally blind to — but they cannot see color so their world is monochromatic. It’s got the polarization signature, which probably increases contrast, and great visual acuity, and they can see at night. Now with that capability, how do they get the color right in camouflage? Nothing I mentioned has anything to do with color, so it’s still an outstanding question and we’re just too ignorant to figure it out so far!
This interview was edited and condensed for clarity and length.
Watch his TED Talk now: