Octopus (22 page)

Jennifer used the computer to make sense of the numbers. To arrive at personality or temperament dimensions in animals, you record reactions they make to certain situations and you establish consistencies. The test-tube brush touch test, Threat, was a good one: reactions varied widely, from jetting away from the brush to the other side of the tank and inking, to turning toward it, grabbing it, and pulling at it. Reactions to opening the tank, Alerting, and to the crab, Feeding, were less striking, but there were differences. For Feeding, some swam to the crab and engulfed it, others sat in a corner and waited for the crab to wander over, and some waited until night to eat.

Analysis of the nineteen different behaviors was difficult, but the computer eventually put the variations into three different personality dimensions. One was shy-bold: a shy octopus would hide when a diver came anywhere near, and a bold one would stand its ground at the approach of a diver. Another was reactivity: if you touch octopuses with a test-tube brush, the reactive one would jet away, squirting out ink; but touch an easygoing one, and it would just sit there. The third dimension was activity: an active octopus would be like our #5 in Bermuda, always out and going, while a passive one, like #30 in Bermuda, never seemed to come out of its home. There are consequences to these differences in behavior: #5 was killed and partly eaten by a predator during our observation period (see plate 28).

After doing this work tracing personalities in octopuses, we made another claim that octopuses should be considered along with “higher” animals, for whom variation like this is taken for granted. Personality, which is a construct to explain variation among individuals, isn't just something we humans and perhaps monkeys and dogs have, but it is found among all complex animals. There are differences too, of course: sociability is a personality
dimension in the group-living mammals, but it's not present for the solitary octopus. But the similarities are striking, and the octopuses add a new scope to the study just by being there.

Bringing the octopus into the study of personalities, the first time for invertebrates, reminds us of how strongly scientific research focuses on a few vertebrates and how little we know about the invertebrates that make up 99 percent of all species on earth (see plate 29). Jennifer coauthored with David Logue a book chapter on personality in invertebrates, which clarifies our lack of such information. Other existing studies on invertebrates have taken differing approaches. David Sinn and Natalie Moltschaniwskyj (2005), for example, continued classic personality research on the little, short-lived southern bobtail squid. Genetics researchers focused on the well-known fruit fly and dug into the physiological and genetic background of simple behaviors like courtship. Behavioral ecologists have studied the evolutionary-linked adaptive strategies that result in our description of shy or bold animals such as spiders, and are gradually coming to see that these behavioral syndromes produce a variety of compromises between staying safe and getting enough food.

Samuel Gosling turned the focus around in 2001, arguing that research on animal personalities can give us a new perspective about human personalities. He argued that through animals, we can learn about the biological basis for human personality reactions and the hormonal and physiological aspects of those reactions. We can learn about the genetic basis: heritability is hard to trace in humans who reproduce after twenty-five years, but is much easier in rats with one year to maturity. Findings can be achieved even quicker for the little bobtail squid, which lays eggs at three months, or in fruit flies with a lifespan of a couple of weeks. He also points out that we can study environmental influences on personality in animals by isolating monkeys or enriching rats' environments in ways that we cannot ethically do with humans.

While octopuses don't fit neatly into this area of research, Sinn et al. (2001) have begun to answer some of the questions about cephalopod personality and temperament. When still a master's student at Portland State University in the late 1990s, Sinn studied temperament in young Californian two-spot octopuses. He deliberately chose this species because it lays big eggs for octopuses and therefore has big young that walk away at hatching and can be more easily reared and tested. By testing at three, six, and
nine weeks of age as well as testing ones from different broods, he obtained some interesting comparisons.

He used the same three tests that we did, and found similar personality dimensions in these tiny octopuses (which are about the size of a human little fingernail, though big for an octopus). And because he tested them over time, he could look at other effects that might be related to genetic programming of changes or situations where ecological influences would matter. Most behaviors were the same ones we saw, but change of pupil size, papillae height, and posture seemed more important in these little octopuses. His analysis picked up four factors explaining 53 percent of the variance, one more factor than ours and 9 percent more variation. He chose four names to describe the factors: active engagement, arousal-readiness, aggression, and avoidance-disinterest—which are much like those we gave to the red octopuses.

The second part of the analysis was equally rich in findings. A theme of vertebrate personality development is “continuity plus change.” Six weeks' testing time doesn't sound like much of a time span, but this species lives only six months to a year. There was change, significantly, between weeks three and six for all the octopuses. These changes were mostly in arousal-readiness and aggression; maybe wariness and aggression need to change in the early, risky life of octopuses. Still, there were big correlations between scores across time periods, so there was continuity as well. This neat fit with vertebrate developmental patterns is particularly thought-provoking, especially since all the octopuses were raised in tiny, bare isolation chambers. Some internal influence, not a variable environment, had to be making the difference. And who knows how different they might have been if they had been out in the vast ocean—one on a rock face full of algae, one in a rubble-filled yacht basin, and a third near a pebbled beach.

The third interesting result came about because Sinn worked with octopuses from different broods. He collected mature females ready to lay eggs from the wild, so he didn't know paternity. Given the chance, female octopuses will accept several males and store sperm from them. When the eggs are ready to hatch, they move past the sperm storage gland where the female releases sperm to fertilize them on their way to hatching. We know only that the baby octopuses from one brood were at least 50 percent related, having the same mother. Still, the pattern of development of temperament dimension was significantly different for these three broods,
with arousal-readiness differing significantly. Some genetic factor was affecting the way these baby octopuses approached their environment, and with a variable environment of the near shore, these inherited differences would probably have been exaggerated. The same kinds of differences exist in newborn garter snakes but within a brood, and this is an interesting parallel because neither species receives parental care. Newborn monkeys are buffered from the environment by their mothers, whereas snakes and octopuses have to make it on their own from birth.

Sinn's work makes us more comfortable drawing parallels between vertebrates and cephalopods about temperament and personality. And his work is comforting in another way: he has picked up our ideas and developed them in his own direction, so the important work of figuring out how and why individual octopuses act differently will continue. But we still wonder about the octopuses we encountered. Did bold #5 in Bermuda have a peaceful childhood, with abundant crabs to eat and no menacing fish? Would its sunny personality have made it vulnerable to the Portuguese fishermen who caught some of our octopuses at low tide? Did shy #30 have a pair of anxious-avoidant parents? And if so, then how did they manage to get together to mate? Maybe his mother's anxiety made her a good caregiver for all those eggs. And what about Leisure Suit Larry? Did a danger-filled childhood wreak havoc on him as it does with men who end up with Antisocial Personality Disorder? Would the octopus Emily Dickinson have been able to tolerate the presence of a male long enough for mating if he'd been able to find her behind the tank backdrop?

9

Intelligence

M
ost everyone has heard that octopuses are intelligent. But it's difficult to define this intelligence. We know that octopuses learn well—that they change their behavior because of information they get from their environment. Common octopuses have demonstrated this learning ability in numerous situations, such as when they have avoided stinging sea anemones on hermit crab shells, drilled at a different location on snail shells because they were blocked from the spire, and learned to take a crab only when it was associated with a striped visual stimulus. People jokingly refer to octopuses as “smart suckers” with “soft intelligence” and “spineless smarts,” but they often wonder just how smart octopuses are. Because intelligence is such a variable thing, made up of different abilities and used in different situations, the question really can't be fully answered.

The book by Marc Bekoff et al. (2002) about animal behavior is interesting because it offers accounts of various animals' abilities by researchers who work with different species—though, alas, nothing on octopuses. Ground squirrels size up potential predators, jumping spiders may use deception, and dogs understand human gestures. These abilities are all different, and each is adaptive in the life of the animal that uses it. Because there's more going on than just simple stimulus-association learning, we like using the term “cognition” for these abilities. Ulric Neisser defined cognition in 1976 as “all the processes by which the sensory input is transformed, reduced, elaborated, stored, recovered, and used,” though every animal will have a subset of ways to use these processes that is matched to its ecology. That means intelligence is not only about getting but also using information. Octopuses use information when they construct dens, make a sequence of different appearances to evade predators, and discover different ways for opening a tightly shut clamshell. Much of the octopus's daily survival is based on getting information and using it well. We cannot talk about how smart octopuses are, but we can talk about how they are smart.

We felt we were onto something about intelligence in common octopuses when we charted their foraging areas in the mid 1980s in Bermuda. We knew that these octopuses had a home in which to hide and went out hunting from it, but we were startled by the systematic way they did this. Mostly hunting excursions were short trips of less than an hour, and the route outward was wandering and indirect. One octopus would set out northeast, skimming the rock face but concentrating on the crevices, feeling its way through an algae patch, and doing webover searches through an area full of small rocks. After getting a few file clams, the octopus would stop in a crevice to eat them. On the way back, it would take a direct path. Often, if the animal were more than a couple of yards away, it jetted straight home, making a triangular path. The next time an octopus went out to hunt, it started off in a different direction, and the third time it went in a different direction yet. This pattern revealed that they were central-place foragers, hiding in the middle of a home range and going out into it to find food. This mode results in the animal covering different parts of its home range each day, keeping near shelter but being able to eat.

This behavior tells us something about memory in the octopus. Systematically coming back home from foraging means that octopuses have spatial memory—memory of where home is. We became convinced of this ability when we watched them take detours. One octopus was coming home from a two-hour hunting trip when it got scared off its route by another octopus. Finding itself 9 ft. (3 m) from where it had started, it followed the rock edge along a new route until it got home again, navigating by what it had learned in the past (see plate 30).

This technique is quite common among a variety of animals for getting around. Female wasps called bee-wolves dig a hole in a sandy area, lay an egg in it, and go off foraging for caterpillars that will be the hatching larva's food. In a pioneering 1932 study, Niko Tinbergen (1972) tested the bee-wolves' location memory, or how they found the hole, in a simple way. He made a set of landmarks by placing a group of pinecones around the hole, and the bee-wolf got used to the cones being there. But when he moved the location of the pinecone circle, the insects came back to where the cones were and not to where the hole was. We tried this same test on common octopuses in their natural environment, using a vivid black-and-white cylinder as a landmark. Our bold common octopus #5 was a particularly useful test subject because it didn't mind going out hunting when a snorkeler was lying in the shallows nearby watching it—not every octopus puts up with being observed. When we moved the landmark after three days, the octopus came back to its home and not to the landmark. We suspect this was because the octopus lived in a rocky area full of other clues as to where it lived, not a flat sandy area like the bee-wolf. We found that the red octopus, which hides in beer bottles out on the open sand, does use landmarks for finding home when we tested it in a circular tank in the lab.