Most species of shallow water octopuses appear to be pretty solitary animals. They live in dens and venture out from them to hunt or find mates; defending these dens and getting busy are the only social interaction that many species of octopuses are observed to have in the wild. I like to think of them as the curmudgeons of the reef environment, keeping to themselves because that’s just the way they like it.

Keep movin', buddy; there's nothing to see here. (Photo by algaedoc)

It might surprise us, then, to learn that Elena Tricarico and her coworkers, working out of the Stazione Zoologica in Naples, just published a paper arguing the octopuses (of the species Octopus vulgaris), can recognize other individual octopuses. While it’s clear that this ability might be important to more social cephalopods (like squids, which form schools), what good could it do for a species with such a hermit-like existence?

It turns out that keeping to one’s self in an area where there are lots of other organisms around requires some social skills – you have to know a little about the folks around you and what behavior to expect from them. For example, if you see the same animal patrolling an adjacent territory each day, it doesn’t do much good to make a huge fuss over it all the time. If you have your territory, and she has hers, it behooves you both to be able to recognize each other so that you don’t waste time and energy chasing off somebody who isn’t actually going to cause you any problems (this is called the “dear enemy” effect.) On the other hand, if a wandering octopus comes through looking for a good nesting site, it would be useful to be able to tell that he’s a stranger so that you could drive him away and keep him from taking over your territory. Thinking about it in these terms, it makes sense that the ability to recognize other octopuses could be a useful ability to have.

To test whether octopuses could do this, Tricarico and coworkers divided up their experimental octopuses into two groups; in one group, pairs of octopuses were housed with a clear divider between them, so that they could see their partner, while in the other group the octopuses had an opaque divider. After letting the octopuses either see or not see each other for 3 days, they watched how these pairs interacted with each other when they were put into the same test tank for 15 minutes. It turns out that pairs that had seen each other before avoided each other more, touched each other less, and spent a longer time ignoring each other when they were placed in the same tank than pairs that had been separated by the opaque divider.

This alone isn’t enough evidence to conclude that octopuses can recognize other individual octopuses – after all, the pairs that could see each other might just be getting used to being around any octopus. To test whether the octopuses had learned to recognize their specific partner or just gotten used to the presence of other octopuses, the researchers did one more test – they put the octopuses back in the test tank, but this time, they put some of them in with the familiar octopus they had been seeing throughout the experiment, and some of them in with an octopus they had never seen before. What they saw was this: when octopuses were placed with another octopus that they were familiar with, they touched each other less, avoided each other more, and their interactions were shorter than when they were placed with unfamiliar octopuses. It looked as if the octopuses had learned to recognize their partner, and responded differently to them than to a strange octopus.

Like all good experiments, this one begs plenty of questions: can octopuses tell who individuals are, or do they just categorize other octopuses as familiar or unfamiliar? Does their ability to discriminate other individuals imply some sort of social cognition, and of what sort (I’d argue that it suggests only very basic social cognitive skills, but opens the door for more investigation,) and, finally, do I need to worry that someday, the octopuses will learn to recognize ME?

That's right, buddy, I'm looking at YOU. (photo by Rowland Cain)

Thanks for reading! I’d like to point out that I took the title of this post directly from the paper it discusses; it was such a good title that I couldn’t think of anything more fitting.

Elena Tricarico, Luciana Borrelli, Francesca Gherardi, Graziano Fiorito (2011). I Know My Neighbour: Individual Recognition in Octopus vulgaris PLOS One : 10.1371/journal.pone.0018710

Over at In the News Karen Franklin, a blogger who focuses of forensic and legal psychology, has brought us the 86th edition of Encephalon. Head on over there for a recap of the scientific mysteries that were covered in this month’s neuroscience and psychology blogging. Brilliant job, Karen!

I need hosts for May and July (also all the months thereafter) – please let me know if you would like to host an edition (I promise it’s not too hard)! Leave a comment here or hit me up on twitter @cephalover.

Recently, the EU passed a directive that will require all of its member states to follow certain guidelines when using any animals for research. This piece of legislation, passed in 2010, replaced an older law from 1986 on the same topic. Besides updating the ethical and technical aspects of the law, it expanded the scope of the law to include more species than the 1986 law:

3. This Directive shall apply to the following animals:
(a) live non-human vertebrate animals, including:
(i) independently feeding larval forms; and
(ii) foetal forms of mammals as from the last third of their normal development;
(b) live cephalopods.

The first question that comes to mind is: why cephalopods? The answer, it turns out, lies in a document published by the Animal Health and Animal Welfare Panel of the European Food Safety Authority – their scientific report revealed that they had initially considered “all invertebrate animals” for inclusion under the law, but ended up recommending that cyclostomes (a group including lampreys and hagfish,) decapod crustaceans (like lobsters and crabs), and cephalopods should be included in the law. They also noted that other invertebrates, like spiders, tunicates, social insects and amphioxus are on the “borderline” of inclusion – that is, they seem to be complex enough (in their behavior and their nervous systems) that it is reasonable to think that they could experience pain or suffering, but there’s not enough evidence to suggest that they do to justify including them in the law. In any case, the only group of animals from this recommendation that ended up making it into the law was cephalopods, with crustaceans being excluded despite the Panel’s recommendation.

The reasons that the Panel cited for recommending cephalopods seem pretty straightforward; cephalopods exhibit what might be called complex cognitive abilities, being able to learn and remember rather flexibly, have large complex brains, and have strong behavioral responses to a variety of stimuli that we’d call noxious. These points, and their relationship to the possibilities of pain and suffering in cephalopods, are far from settled issues, and there’s a lot of arguments that can be made about why they may or may not be adequate justification for including cephalopods in the directive. In a sense, though, it is too late for these arguments; the directive has already passed, and will be in force as early as 2013.

As one might expect, this whole shebang was big news to cephalopod researchers. As I mentioned a few posts ago, a conference (dubbed Euroceph) was called so that cephalopod researchers could get together and talk about what the new law means to them and their work, and what needs to be done next. And there is a lot to be done.

The directive requires that certain criteria be met when using any vertebrate or cephalopod in research: for example, steps must be taken to minimize the animal’s pain and suffering, the animals used should be (if possible) bred for the purpose of research by regulated suppliers and not taken from the wild, and kept in enclosures that “are appropriate to their health and well-being.” One might run into some problems in applying these standards, which have been used in one form or another for regulating the use of vertebrate lab animals for many years, to cephalopods; for example, there is very little known about to biology of how cephalopods might feel pain, and what the consequences of that pain might be to a cephalopod’s health and behavior. There are only a few anesthetics that are used for cephalopods, and since we know almost nothing about the (presumably existent) pain system of cephalopods, we have no drugs to give them as pain-killers – indeed, it’s hard to even know where to start looking to identify drugs that would work as analgesics in cephalopods.

Another problem that came up repeatedly at Euroceph was the requirement for captive-bred animals. So far, there have only been a few limited successes at breeding cephalopods in captivity – among these, the only real successes have been with cuttlefish. Even in this case, though, captive-bred animals appear to behave differently than their wild-caught brethren (which isn’t really a surprise, if you think about how different the two lifestyles are;) perhaps more troubling, captive-bred cuttlefish seem to lose their ability to produce healthy offspring over several generations, limiting the extent of captive breeding programs. For researchers who want to study the behavior of cephalopods as it might be relevant to their lives in the wild, there is “a fundamental scientific problem” with requiring the use of captive bred cephalopods, said Rogen Hanlon, a cephalopod researcher at the Marine Biological Laboratory at Wood’s Hole. ) “If you want the best model [of cephalopod behavior], you use nature’s fittest, and that’s what you get from wild-caught animals.” Having to use captive-bred cephalopods for behavioral research could require research conducted using wild-caught animals that has been relied upon for decades to be re-done with captive-bred animals; even after this, it would still be difficult to predict what this research would mean in terms of how wild cephalopods actually behave.

While the EU directive contains very specific guidelines for the care of common lab animals like rats and rabbits, it contains almost no specific guidelines about caring for or handling cephalopods. This is because, while there is a long history of requiring that lab mammals be dealt with in a certain way (ie. they must have so much space, be given such-and-such a drug before each procedure to reduce pain, be fed every so often, be kept at such-and-such a temperature,) this is the first time that the research community has been required to come up with a standardized set of guidelines for using cephalopods. This might actually be an advantage to cephalopod researchers – they’re in the position now to shape these guidelines themselves, since there are virtually no other sources of information about how it is best to keep cephalopods in captivity. Hopefully, with the help of forthcoming regulations that are tailored to suit cephalopod research in particular, and more research into the health and husbandry of cephalopods, cephalopod research will continue without too much trouble.

Thanks for reading! Here, have a treat.

Some more reading, if you’re interested:

EU directive 2010/63/EU, on the protection of animals used for scientific purposes (the current law) (pdf)

EU directive 86/609/EEC, regarding the protection of animals used for experimental and other scientific purposes (the old law) (pdf)

The EFSA Scientific report: “Aspects of the biology and welfare of animals used for
experimental and other scientific purposes” (pdf)

Shallow-water octopuses are generalist predators – this means that they can eat a variety of other animals – and good ones too. They have a few different hunting strategies, with the commonest ones involving the octopus groping along the reef, feeling for food with its arms (although octopuses have been reported to hunt by ambushing (pdf link) as well, striking their prey after spotting it.) You can see the groping strategy at work in this video:

It is clear from previous research that octopus arms are capable of movement, even relatively complex movements, on their own. Thus, when an octopus gropes its way around a reef, it might be that it’s central nervous system is doing very little to control its arms; rather, it seems likely that they move mostly “on their own”. Tamar Gutnick and her colleagues at the Hebrew University of Jerusalem recently published a study that investigated if and how octopuses (of the species Octopus vulgaris) can use information from their central nervous systems to control the movement of a single arm. I’ll let them tell you about it:

(By the way, I love video abstracts/experiments. Thanks, guys!)

The researchers took 7 octopuses and trained them to reach into a clear plastic “maze” where they could choose to put their arm into one of three areas. One of the arms of the maze had a piece of food in it. Since they were only given one chance in each session – if they chose the wrong arm in a session, they weren’t allowed to try again – the octopuses learned to find the food by looking at it through the clear walls of the maze and then make the appropriate arm movements to get it. After the researchers covered the clear maze with masking tape, the octopuses, who could no longer see the food, weren’t able to do the task any more – they got about 1 in 3 trials right, exactly what you’d expect if they were choosing randomly.

The results of this study tell us that octopuses can use visual information to direct the movements of their arms, and that they seem to get more accurate with practice. What we don’t know, however, is how an octopus’s brain could pull this off. It’s clear that simple movements are controlled within the arms themselves, as a disembodied octopus arm can make some movements by itself, but it’s unclear how the “higher-up” parts of the brain that receive visual information from the eyes could mix it with tactile information from the arm to direct these sorts of movements.

The skeptic in me says that there might not be much to be excited about. After all, we’ve known that that octopuses use their vision to do things like find their way around, and size up potential food/predators for a long time. The procedure used, even if it’s new, is sort of limited; it’s essentially a simple detour task, where the animal can see its reward but has to take a complicated route to get to it. As Zen Faulkes pointed out in his post on this study, (which is so cleverly titled as to put me to shame), the octopuses weren’t even very good at learning such an apparently simple task. Compare this to the scores of learning tasks that other laboratory animals like rats (and people, for that matter) whiz through, and it seems like a small step. Some experiments using tasks like this fail while others succeed, and there’s no clear consensus as to how and why octopuses learn (or fail to learn) in certain situations, making it even harder to say anything about how octopuses learn.

Nevertheless, there’s some room to be excited; it’s a small step into an mostly unexplored field. Think about just how foreign an experience this was for the octopuses in the experiment – not over the time scale of the experiment, but over evolutionary time. For millions of years, the ancestors of this species have been hunting on the seafloor in shallow waters, where it’s very unlikely that they’d ever encounter a hard, transparent surface that they might have to move around to get food. Even still, when they’re presented with such a situation, they can navigate it, even if they do it with some difficulty. The behavior of these octopuses, then, seems to me to have evolved not only to work well in a specific situation, but to work (at least minimally) in a wide range of situations – their behavior has evolved to be somewhat flexible. In fact, this is a strategy that is used by all animals that can learn (which seems to be most of them) that helps them deal with the fact that there is no such thing as a perfectly stable and predictable environment, and that behavior needs to adapt to deal with this. For example, your ancestors (if you were an octopus) might have fed on a few specific species of crab for the past few hundred years – if something about the environment changes, you need to be able to learn to hunt something else, or you (and your species) are doomed. Looking at it in this light, it’s not very surprising that a laboratory filled with mazes and puzzles built by scientists would push the limits of a cephalopod’s behavioral flexibility – this is a huge change from the environment the animal evolved in. To quote Zen Faulkes, “the point is not that the animals are slow to learn; the point is that they can learn to do this at all.”

This research is also exciting because it begs questions about how the nervous system of the octopus can do this task. In more familiar research animals (that is, mammals), we know that specific parts of the brain (areas of the motor cortex) control the contraction of specific muscles. Besides this, we’ve identified a whole host of brain structures that play various roles in putting together these movements and in using information from the muscles, skin, and eyes to control and refine them. In mammals, both motor and sensory systems are put together in a such a way that their arrangement in the brain corresponds to their arrangement in the body – this is called somatotopy. (Check out this neat little demonstration of the concept by Jaakko Hakulinen.)

According to another study published in 2009 by researchers from the same university, this doesn’t appear to be the case with the octopus. The investigators in that study couldn’t find any clear relationship between activity in different parts of the octopuses’ brain and different movements. While we know where the information from the eyes goes in the octopus brain (to the sensibly named “visual lobes”,) it’s unclear where it goes from there or how it might interact with the neurons that control the arms, or how this information might be put together with sensory information from the arms. How exactly an octopus’s brain uses vision to control ongoing movements, then, is the most exciting kind of scientific problem: an unsolved one.

Thanks for reading!

Zullo, L., Sumbre, G., Agnisola, C., Flash, T., & Hochner, B. (2009). Nonsomatotopic Organization of the Higher Motor Centers in Octopus Current Biology, 19 (19), 1632-1636 DOI: 10.1016/j.cub.2009.07.067

Gutnick T, Byrne RA, Hochner B, & Kuba M (2011). Octopus vulgaris Uses Visual Information to Determine the Location of Its Arm. Current biology : CB, 21 (6), 460-2 PMID: 21396818

Back in September, the European Union passed a directive regarding the use of animals in research. This directive stated that all members of the EU should enforce certain guidelines for the care and use of animals in research; things like making sure that research animals have a certain minimum cage size, are looked after by trained veterinarians, and are handled, experimented on, and euthanized in humane ways. They don’t include all animals, though: species of animals are only covered under this law if the EU has determined that they can “sense and express pain, suffering, distress and lasting harm.” Let’s take a look at that list, shall we?

3. This Directive shall apply to the following animals:
(a) live non-human vertebrate animals, including:
(i) independently feeding larval forms; and
(ii) foetal forms of mammals as from the last third of their normal development;
(b) live cephalopods.

That’s right, cephalopods made the cut as being ethically worth looking out for. Why is there an exception made for them, though, out of all of the invertebrates?

In addition to vertebrate animals including cyclostomes, cephalopods should also be included in the scope of this Directive, as there is scientific evidence of their ability to experience pain, suffering, distress and lasting harm.

By the time I reached this point in reading this document, it was clear to me that it was not written by scientists. Scientists probably would have talked about how the research suggests that cephalopods are rather likely to have the capacity for suffering and distress. You only ever really show that an animal *looks* like it’s suffering, in any case. Word choice aside, though, I think that it’s a worthwhile inclusion – it’s at least as easy for me to believe that an octopus can suffer as it is to believe that a lizard or fish can suffer.

That’s not why I brought it up, though.

In response to this directive, a group of cephalopod researchers decided to have a meeting. They’re calling it Euroceph, and besides being a forum for discussion about this particular EU directive, it’s also a scientific conference focused entirely on research in cephalopods, aimed to bring together in one place as many cephalopod researchers as possible to talk, share, network, and learn. And (here’s the most exciting part of all,) I’ll be there! Thanks to the generosity of the organizing committee (who are covering my registration fee), and my wonderful parents (who are helping me with airfare,) I’ll be at Euroceph to not only stroke my own academic interest in behavioral and neural research, but also to report on everything that is going on in the world of cephalopod research. Because I am the only blogger in the world without a laptop, I probably won’t post directly from the conference, but I’ll fill the weeks following it with posts that will hopefully convey not only my excitement but also all the cool stuff I learn about at Euroceph!

Thanks for reading!