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
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.
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
While I was reading Zooborns the other day, I came across this wonderful video of a mother Octopus vulgaris (common octopus) at the California Academy of Sciences hatching her eggs in captivity – she rubs them with an arm and a cloud of baby octopuses explode from the egg cluster!
Breeding is at once exciting and depressing in octopuses. With many species of octopus, they die after they breed. They’ll stop eating in order to tend the eggs, and die shortly thereafter. In addition, the young prove to be very difficult to rear. The young of so-called “small-egged” octopuses initially float freely in the water (they are planktonic at this point) and then settle down onto the floor of the ocean when they get a bit bigger – it’s not known how they should be fed while they are in the planktonic phase, or how to accomodate their “settling out” of the water. Who knows, though – the Steinhart Aquarium was the first facility to successfully breed dwarf cuttlefish in captivity (click through for lots of great cuttlefish photos.) These octopuses are more of a challenge, though; only time will tell, and it’s probably not realistic to be very optimistic.
I’m back on my mission of keeping you on the cutting edge of cephalopod-related video content online! Today’s selections all feature incirrate octopods, doing what they do best: looking incredibly weird as they slink around. The first two videos (by Tapio Kuiri and Bouju1, respectively) show hunting behavior, with some great interbrachial web shots. The last one, I have no source on, but if you like seeing writhing tentacles set to Chinese (I think) music and narration, it’ll be right up your alley! (If somebody can translate/give some background on the video, we’d all be very appreciative.)
In the mean time, though, I wanted to bring you some more information about the family of squid that this guy belongs to (the Chiroteuthid family.) It turns out that I’m having some trouble digging up information on these species, as they’re relatively understudied – in my searches, though, I came across something totally unrelated (and totally awesome) that I just have to share with the internet. So, I’ll have to leave you wanting that primer on Chiroteuthid biology (I’ll probably get to it after finals) for this blurb on a very unusual octopod.
In 2004, Mark Norman, Renata Boucher, and Eric Hochberg published a description of a previously unknown species of octopod from several male specimens that was gathered in the western Pacific Ocean. They placed it in its own genus, calling it Galeoctopus lateralis. In most respects, this guy appears to be pretty typical for a deep-water octopod – in one respect, though, he’s strikingly different. See if you can tell what’s unique about this guy from this drawing of his body plan:
From Norman, Boucher, and Hochberg (2004)
Note the conspicuously short arm – more precisely, the third arm on the right side. This is the arm that contains the ligula, the organ that male octopuses use to inseminate females. Let’s take a closer look at this:
From Norman, Boucher, and Hochberg (2004)
It’s a bit hard to see in this photo, but on the oral side of the third tentacle (that is, the side that usually faces inwards, towards the mouth) there is a small opening. Inside this opening are tiny “teeth-like lugs”, which the authors suggest that males use to remove the sperm bulbs that previous males have left inside of the female they are mating with, thereby increasing the competitiveness of their own sperm. This is a pretty standard evolutionary strategy – if you prevent the other guy’s sperm from doing their thing, your own sperm (and thus your genes) have a better chance of successfully being incorporated into the next generation of your species.
The authors hypothesize that this unique structure is complementary to an equally unique bit of anatomy that is found in females of the species, an enlarged muscular appendage of the oviduct:
Male Galeoctopus may use the mouth-like transverse groove of the muscular ligula to grip and rupture the sperm bulbs of previous suitors… The muscular flange on the distal oviducts of the female may be related to a vigorous mating process, these muscles potentially anchoring the oviducts during copulation to prevent them tearing free from the visceral wall.
NORMAN, M. (2004). THE SHARKCLUB OCTOPUS, GALEOCTOPUS LATERALIS, A NEW GENUS AND SPECIES OF DEEP-WATER OCTOPUS FROM THE WESTERN PACIFIC OCEAN (CEPHALOPODA: OCTOPODIDAE) Journal Molluscan Studies, 70 (3), 247-256 DOI: 10.1093/mollus/70.3.247
To get things started, here’s a video of an octopus with a Mr. Potato Head Toy (and other things):
You’ll see why this is relevant in a minute. Now on to the post!
“Enrichment” is a psychological term that’s been thrown around a lot. It’s become a buzzword in publications about education, perhaps rightly so given its huge impact on the field of developmental psychology. It has been the subject of intense study in psychology, and continues to be the subject of study. But what exactly is it that we are referring to when we use the term “enrichment”?
Before I get to that, let’s take a step back and consider how brains work. Brains, in the sense that I am talking about, are simply big networks of neurons (there are other types of cells, but we can ignore them for now.) These neurons get sensory input from the body, talk amongst themselves, and send out signals that cause the organism to behave in a certain way. This is, in a nutshell, what brains do – they generate behavior. Importantly, though, they don’t just generate any behavior at a given time; they generate the appropriate behavioral response to the immediate situation. Even more impressively, in some animals, they generate the response that will lead to a positive outcome in some hypothetical future situation (for example, when birds hide food to recover later.) Thus, brains work because they can process incoming sensory information into relevant and adaptive behaviors. Neurons can do this because they are connected to each other in complex but well-controlled and highly-specific ways. Much in the way that an electrical device will only operate if all of its components are connected correctly, brains will only work if all of their neurons (or at least most of them) are “wired” together into functional circuits.
It may come as no surprise, then, that brains only wired the way they are because of the sensory input they receive. During brain development (and, to a lesser extent, throughout life,) neurons require sensory input and behavioral output to form proper connections as well as get rid of improper connections. At the cellular level, this phenomenon is called activity-dependent or experience-dependent plasticity. One can think of it this way: connections between neurons (called synapses) that are used a lot and produce functional behaviors get stronger; that is, they become more efficient and transmit larger signals from neuron to neuron. Synapses that are not used, or that don’t contribute or contribute negatively to the function of a certain circuit become weaker; that is, they become smaller and less efficient, and may even disappear altogether.
This can be demonstrated directly by looking at neurons that process incoming visual information from the eyes. Suppose we were to raise one group of animals (lets say, ferrets) completely in the dark, and another, otherwise identical group of animals normally. Then, we kill both groups of animals and look at the neurons in their visual system (for example, in visual cortex.) The group that was raised under normal light will have, by definition, normal connections between the neurons in the visual system – specifically, these neurons will form functional circuits that allow animals to sense and respond to their environment. In the animals that were reared in the dark (called, sensibly, “dark-reared” animals,) we’ll see a host of abnormalities – cells will have the wrong shapes, end up in the wrong places, and have the wrong connections. Besides this, we could demonstrate some deficiencies in visual perception in the dark-reared animals. Taken together, these results, which have been replicated in a variety of vertebrates, strongly support the idea that sensory systems need input during development in order to develop properly.
It’s a small logical step to tentatively extend the principal of experience-dependent plasticity to brain functions that are more complex than immediate sensory analysis. In the mammalian cortex (which is involved in such complex behaviors as navigation, auditory and visual perception, social behavior, speech, thought, and so forth,) normal development is dependent on the experience of the animal in question during development. The input that these brain areas deal with is almost unthinkably complex. Their function often involves the monitoring the interaction of large parts of the organism with the environment over an extended period of time. For example, cortical areas involved in directing complex hand movements (say, playing a musical instrument) receive their input in the context of a feedback loop that involves planning a movement, executing it, and then determining whether the movement was successful and, if it was not, how it needs to be changed in order to be successful the next time. More abstract cognitive processes become even more complicated, as the brain areas responsible for these have to take into account such complex “stimuli” as the animals current and previous emotional states, inferred emotional states in other animals, the value of various hypothetical outcomes to the organism, prior cognitive states the animal has had, and so forth.
Here’s where the idea of environmental enrichment comes into the picture. The logic goes like this: because neural development is facilitated by the nervous system’s interaction with the environment, and because the more integrative areas of the brain (like the cortex) interact with the environment in very complex ways, normal brain development requires interaction with a very complex environment. If this theory is true, animals raised in very restricted environments (we might call them “environmentally impoverished”) should show maladaptive or sub-normal behavior as adults. In fact, this prediction has been borne out in many studies, which find that (among other things) environmentally impoverished animals (and, although it has been less directly demonstrated, people) have altered learning abilities, exploratory behavior, cognition, stress reactivity, and social behavior.
A corollary of this theory is the idea that nervous systems which have evolved to deal with the environment in very complex ways function abnormally when they do not have complex environments to deal with, much like the way that muscles atrophy if they are not used. Part of successfully engaging a complex environment is continually interacting with and exploring it – indeed, many animals have evolved a propensity to explore and manipulate their environment. Thus, animals with complex behavioral repertoires require complex environments to interact with in order to maintain normal brain function. This theory predicts that a lack of complexity in some animals’ (or people’s) environments should lead to aberrant behavior, and that such behavior can be corrected by providing an appropriately complex environment to those animals (or people.) This prediction is borne out in a variety of studies that show that, in captive adult animals, providing more complex environments leads to lower stress levels, less aggression, and fewer pathological and stereotyped behaviors.
Dr. James Wood’s article, “Environmental Enrichment in the Giant Pacific Octopus; Happy as a clam?” makes the case that aquariums should provide environmental enrichment for captive octopuses. I won’t follow his arguments exactly, but I will examine some of the same questions that he covers, and make reference to and critiques of his work as I find it relevant.
The big question is this: Should we provide environmental enrichment to captive cephalopods? Let me rephrase this: do the benefits of providing environmental enrichment to cephalopods justify the costs incurred by doing so?
First, let’s consider the possible benefits. Anderson and Wood point out several:
1. Captive animals should be kept healthy and allowed to behave normally. Behavioral health is as important to the longevity and quality of animal’s lives as is physiologic health. The real question here is whether cephalopods have complex enough behavior that they might show pathological behavior in response to captive conditions. Put in a more cognitive frame: are cephalopods smart enough to be hurt by captivity and, consequently, to benefit from enrichment?
Indeed, it is hard to tell whether cephalopods could benefit from enrichment. To the question of how we can tell if giant pacific octopuses could benefit from enrichment, Anderson and Wood succinctly conclude: “Simply put, we cannot.” Because cephalopods have evolved under predation from fishes, they reason, they spend most of the time during which they are not hunting hiding in their dens. It’s hard to tell if this is “good” for the octopus (after all, it seems like it would be nice not to have the daily stress of fleeing from predators and risking death during hunting) or bad (because, if cephalopods can become bored, this behavior certainly seems like it would be really boring.) In addition, little is know about how behavioral pathology might look in cephalopods, because we know so little about their behavior in general.
In sum, cephalopods may or may not benefit from enrichment. Given how complex their behavior appears to be, and the likelihood that at least some cephalopods possess cognitive capacities to rival at least some vertebrates, it seems like there’s a reasonably good chance that they could. This isn’t a convincing case in itself – it really depends on the costs of providing enrichment to cephalopods. If the costs are low, this might be enough of a reason to do it; with increasing costs, it becomes an increasingly bad bet.
2. Animal enclosures should meet the expectations of the public. Showing the public what they want to see – which is, it seems, natural-looking enclosures that animals can interact with) will lead to financial success and public support for zoos and aquariums. Researchers, institutions, and the enterprise of biological science in general stand to benefit from the increased public support that comes with presenting a public-pleasing image of animal husbandry in research. Also, if the public sees naturally-behaving animals instead of pathologically-behaving animals, they learn more about the animal’s behavior. A primary function of zoos and aquariums is to educate the public about animals, and so the potential to improve on this education is an important possible result of providing enrichment to cephalopods.
This is an interesting idea to me. Octopuses are popular aquarium animals, but not very popular research animals. The public face of animal research is usually mammalian, including rats, mice, rabbits, and primates. It’s doubtful to me that researchers would benefit from an improved public image if all octopuses used in research were given lots of enrichment. In zoos and aquariums, though, this seems like a valid concern. Indeed, it could offset the monetary costs of providing enrichment for these institutions, which allows less tangible benefits (like the possibility of relieving the suffering of bored octopodes) to be given more weight in deciding whether or not to provide enrichment for captive cephalopods.
3. Finally, zoos and aquariums often care for animals with the goal of eventually releasing them into the wild. Animals whose behavior is dependent on learning need to practice skills that will allow them to succeed, such as hunting, defending from predators and rivals, and maintaining good relationships with other individuals of their species. The Seattle aquarium, for example, does this with their giant pacific octopuses. They catch individuals, hold and display them for a few years, and then release them into the wild so that they have a chance to breed.
It’s doubtful to me that enrichment benefits cephalopods in this way. I can’t say that it’s impossible, but it seems unlikely. While cephalopods are able learners, the basics of cephalopod behavior – feeding, escape, and mating – appear to be largely innate. For example, octopuses learn things in order to adapt to the specific micro-environments they end up in. The characteristics of these environments are impossible for aquariums to predict, and so they cannot be simulated. Feeding a cephalopod common local prey species so that it learns how to eat those species efficiently might help it succeed if it is released, but besides this one example there seems to be relatively little to do in the way of “preparing” a cephalopod for release.
Before I hash out some of the costs of providing enrichment to captive cephalopods, let’s consider what providing such enrichment entail. Anderson and Wood suggest several ideas for giant pacific octopuses, most of which could work with other species of cephalopods. The one that sticks out to me is feeding the animals a variety of live prey. This would provide them with a good deal of activity, a variety of problems to solve (how to catch and eat different species of prey,) and is very entertaining for the public to watch. Some cephalopods (cuttlefish come to mind – I’ve read cuttlefish keepers complaints about this) will only reliably eat live food, anyways.
The authors also suggest that the octopuses be given objects to explore, which can be smeared with fish drippings or have food hidden in them to attract the octopus and encourage exploration. In my favorite quote of the paper, they recount a particular use of this technique:
Wood and Wood… hid food in a play ship – the octopus had to “sink” the ship to get the proffered food. Such a demonstration with a large octopus… would interest the paying customers of a public aquarium by invoking a “sea monster” image.”
The future of cephalopod husbandry.
They also suggest the use of “training” to provide enrichment to octopuses (I put “training” in scare quotes, because some of their specific suggestions, such as smearing fish-smelling fluid on parts of the tank, don’t necessarily involve learning.) This seems like a moot point to me. There are two ways in which you can train a cephalopod – by rewarding it with food, or by punishing it with electric shocks (or some other unpleasant stimulus.) In the first case, you might as well simply give the animal the food, the capture of which seems like it would provide most of the activity inherent in training. In the latter case, well, who’s going to argue that training an animal by electric shock improves its quality of life or reduces its suffering (assuming that the training isn’t absolutely necessary, such as teaching it not to attack people or run into traffic, etc.)?
What would be the costs of providing this sort of enrichment to cephalopods? In my estimation, they would be small. Here’s my reasoning:
It should be relatively easy for aquariums, especially those near coasts, to obtain live prey to feed to cephalopods. By advertising the feeding times (as is done with the animals like sharks, dolphins, and sea lions) aquariums could turn this into a way to entertain visitors and draw more business. The increased popularity of octopus exhibits would likely make up for the extra cost of providing more live food. One of the complaints I hear about the giant pacific octopus exhibit at the Niagara Falls Aquarium is that it just sits there all the time. In the interest of furthering public interest in cephalopods, I make sure to write “Please publicize octopus feeding times!” in their guestbook each time I visit. I’m sure that if they did this, their visitors would be more interested in the octopus and happier with the aquarium overall.
Similar reasoning applies to constructing interesting enclosures that encourage cephalopods to explore. The public likes to see animals doing things, and the increased public interest will more than make up for the expenses of outfitting an octopus tank (which can be as cheap as a few plastic toys) These forms of enrichment are probably very cost effective, at least for public aquariums, even if they have only a small chance of benefit the captive animals.
When we consider animals used for research, the costs become larger. Giving animals a less monotonous environment may exaggerate inter-individual variation. It is usually argued that enrichment produces consistently healthy experimental animals, and so reduces variation in experimental results. The research that is used to make this argument in the case of mammals, however, has not been replicated in cephalopods. Without such evidence, it’s hard to say what effect different kinds of enrichment would have on behavioral experiments with octopuses. Such evidence would be rather expensive and time-consuming to obtain, and providing enriched environments to experimental cephalopods on the assumption that it would improve results could be, if that assumption were wrong, very costly as well. If behavioral research on cephalopods becomes more popular, this will become a more urgent question, and somebody will have to take on the task and expense of answering it.
Generally, providing enrichment for captive cephalopods seems worth it. Given the (even relatively slight) chance that they could benefit from basic environmental enrichment and the small cost of such enrichment, there’s no reason not to do it. The deal only becomes sweeter when you take into account the benefits to aquarium popularity and public education. Even if the cephalopods don’t benefit from it, it can hardly hurt.
Thanks for reading!
Anderson, R., & Wood, J. (2001). Enrichment for Giant Pacific Octopuses: Happy as a Clam? Journal of Applied Animal Welfare Science, 4 (2), 157-168 DOI: 10.1207/S15327604JAWS0402_10
After a moray eel attack (the octopus footage starts about 5 minutes into the video):
I wonder how that octopus coped afterwards. It seems to be swimming just fine, but it’s likely that, even if it could still function, it would get an infection or fall prey to another predator it was no longer strong enough to get away from. Thanks to Glenn Patton for that great video!
Next on this week’s cephalopod video revue, Let’s take a look at some cuttlefish. I never get tired of watching these guys change color.
Both of the users who posted these videos (ScandanavianDiveTeam and Tmukouhara) have a bunch of other dive videos, so click through and check them out.
Finally, the Shedd Aquarium in Chicago just posted a neat video starring one member of the cephalopod family that never gets enough attention: the nautilus.
An article came out this week in the US News and World Report covering research being done on Humboldt Squid populations off of the Pacific coast of the US (including some quotes by newly-named MacArthur fellow and oceanographer Kelly Benoit-Bird.) They mostly avoided the “vicious man-eater” stereotyping of the squid that I so deplore, but managed to squeeze in a toned-down version of it that I found quite funny:
Mexican fishermen call them diablos rojos, or “red devils,’’ because they are extremely aggressive. “I don’t think I would choose to get in the water with them when they are actively feeding,’’ Benoit-Bird said, noting, however, that they lose their propulsion when captured. Even so, “you don’t want to stick your fingers in their mouths,’’ she added.
Pretty much any animal is dangerous when you stick your fingers in its mouth. I have 2 pet rabbits – cute little fluffy bunnies – and I wouldn’t recommend sticking your fingers in their mouths, especially while they are eating. Somehow, this testimony doesn’t quite convince me.
Finally, I’m still looking for submissions for Encephalon , the psychology/neuroscience blog carnival. Drop me a line on twitter ( @Cephalover ) or via email ( mike.lisieski (at) gmail (dot) com ) to submit a post!
As I promised in the title, here are some baby octopodes (Octopus rubescens, the east Pacific red octopus, to be exact.) These guys are so small that you can see the individual chromatophores on them (the reddish spots)!
For comparison, here’s a photograph of an adult O. rubescens, graciously provided to the world by Taollan82:
Those little buggers have quite a bit of growing to do!
Moving on: “Sharktopus”, the long-awaited film about a Navy-engineered half-shark half-octopus monster, airs tonight on Syfy. Not having a TV, I won’t be watching, but it looks pretty incredible. Check out the trailer:
Two things I noticed: first, whoever performed that theme song deserves lots of credit – it makes the preview. Secondly, Sharktopus seems to have an appetite for skinny women in bikinis. You’d think that, being a presumably efficient predator, it would be attracted to prey with more body fat (eg. prey that would yield a higher calorie intake to expenditure ratio,) and it seems like there’s no danger that a large person could hurt it – but it still almost exclusively goes after skinny beach babes. How could the producers fail to consider the probable features of Sharktopus’s energetics? They must not be biology geeks.