Dispersal Patterns

In this post, I want to discuss an important aspect of primate group behavior: dispersal. Most baboons spend their entire lives as part of a single group, with one main exception. As males approach adulthood, they will disperse, leaving their troop of birth to join a new troop, where they will (usually) spend the rest of their lives.

Female dispersal is rare, for dispersal is hazardous. Leaving the safety of the troop is a problem, but leaving the safety of known territory is also problematic. It's much easier to get away from a predator when you know the location of the closest tree. So why do primates disperse at all? For the most part, dispersal is the only way genes are exchanged between groups of primates. There must be some mechanism for individuals to change groups, or else inbreeding will become a problem.

Male baboons typically leave a troop around the age of 8 or 9. Leaving at that time benefits everyone: the males are strong enough to have a decent chance of surviving on their own (barring bad luck, which happens), the male will have better chances at mating and producing healthy offspring in another troop, and the female relatives of the dispersing male improve their own fitness by encouraging him to leave the troop and reproduce elsewhere.

Females will often refuse to mate with males born in their group, even if the female and male are not directly related. The male can force himself on the female, but that kind of behavior usually isn't worth the extra energy investment. If a male forms a mating pair with a female who doesn't want to be paired with him, she will be looking for any extra-pair copulations she can find, and the male isn't going to get any sympathy from the rest of the troop.

If a male isn't strong enough by age 9? He can usually stick around for a little while longer, but chances are he won't get much stronger, and at some point, the males and females in the troop are likely to let him know that he isn't wanted any longer. In all scenarios, the male will usually become ostracized if he does not leave.

Dispersal is difficult to study. Researchers have to follow young adult males, which is not particularly easy even when they stay within a troop. They need to stay close to the males, so they don't miss when they leave the troop, and then follow them through mostly empty bush, savannah, forest, until they join another troop. Little is known about the daily life of a dispersing male. As far as I am aware, no one has made a career of following dispersing males. Much of what we know has been observed by researchers following troops, who have tried to glean as much as possible from events where new males have joined the troop from outside.

Around the Cape, dispersal is a major issue because the baboons' natural predators have been removed from the ecosystem by humans. While in the process of dispersing, many males are caught by leopards or lions or hyenas. If a male isn't part of a troop, he will more easily fall prey, particularly if he is weak compared to other dispersing males. Without any large predators around, there is a higher male population, and usually not enough space among the existing troops to sustain all of them.

In the second troop, there has been a large influx of males more recently. Bopple seems to be hanging onto his status as alpha, but there have been as many as nine males in a troop of about 50. The troop is almost constantly in chaos. Males need to be able to keep apart from one another, and with that number of males in a single troop, it is simply impossible for them to keep distance between themselves. As a result, they chase each other, they chase the females, and they fight. It isn't a pretty sight. Watching male baboons face-off against each other is exciting, but it does get old, and that sort of volatility doesn't make data collection easy.

For additional reading, and more rigor (though I don't know how outdated their findings are, check out Alberts and Altmann, 1995.

Lighter Fare

I don't know enough Japanese to understand what the narrator is saying. I'm not even sure what's going on, this doesn't look like a normal mating scene. The monkeys are probably acting weird because they are in a cramped space and the keepers have been trying to get them to mate for hours. There is clearly some creative editing taking place.

Also, these are mandrills, another member of the Papionini Tribe, but they are not baboons. And a final word of warning: this video is NSFW.

Keep It Down

Cheating monkeys try to hide their infidelity

Wild gelada monkeys change their behavior to avoid getting caught cheating on sexual partners. When the dominant leader male in a gelada monkey herd is away, females take up with bachelors, but they're discreet, making fewer sexual noises to avoid detection.

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Original publication is here. I wish that 4 years ago, I'd been aware that this kind of work could get you a paper in Nature (even if the data in this paper have been under collection since 2009). According to the Nature article, geladas engage in extra-pair copulations (ECPs) i.e. when a female has intercourse with a male who she is not paired with. Pairs are usually established by the male following the female around all day and physically preventing any other male from mating with her. So ECP opportunities don't present themselves very often, but then again, there are many hours in the day.

About 10% of gelada copulations are ECPs. The number of ECPs goes up as the distance from the paired male increases, particularly beyond 20 meters. Exactly what you would expect. However, I found the large number of silent copulations surprising. Allow me to digress for a few paragraphs:

One day, I was up on the mountain with the second troop of baboons. The group found their way out of a tall pine forest, into a cultivated field where they could pick grain. Much of the troop was wary of entering the field, probably because the baboons recognized that it was an open, exposed space, which the forest was not. So a large portion of the troop remained in the woods, playing, grooming, socializing.

Bopple, the young and inexperienced alpha male, ventured into the fields. For all of that day, he had been following Nikki, a high ranking female in estrus. Bopple had left her side for this excursion. We were standing at the edge of the forest, so we could watch the animals in the trees as well as those who had stepped into the field to forage.

I heard a female copulation call, which is nothing unusual. But then Bopple came running. He jumped onto a large boulder at the edge of the trees and stared intently at the bushes, from which issued the call, for about a minute. Eventually he relaxed, but stayed up on the boulder, perhaps continuing to keep an eye out. Nikki was nowhere to be seen, for many minutes after.

Nikki engaged in an ECP, and she was smart about it. Bopple didn't take revenge immediately, at least not within a 5 minute window. He might have done so later; he's a male baboon, so beating up on females is a common occurrence. I don't think he could have attacked the offending male, since (as far as anyone knows) there was no information to identify the individual. Displacement aggression would be much more likely.

Geladas are not baboons, even though they are sometimes called "gelada baboons" and are closely related to true baboons. They are part of the same "Tribe" (a non-traditional taxonomic rank that sits between Family and Genus): Papionini. Macaques are also in this Tribe, so the similarities between Species may not be strong. Since doing background research in preparation for this article, the differences between baboons and geladas have never been more apparent to me.

In a previous post, I found an audio sample of a chacma baboon copulation call. Have a listen. Then, watch this video. Copulation calls have been the subject of much study over the years and findings are myriad, but I have never heard baboons copulate as quietly as these geladas. I would not have dreamed this was possible, since it looks like geladas are going through exactly the same behaviors when they mate. According to the Primate Info Network, when in estrus, female geladas usually only mate 2 to 5 times a day. From personal experience and from published evidence, I would be comfortable saying that female chacma baboons copulate at least a hundred times a day.

From this, I infer that the copulatory behaviors of geladas are quite different from those of baboons (or any other species), and if their copulatory behavior is different, odds are that their deceptive behaviors will be different as well. Geladas are a strange species, what with the red swellings on their chests and almost entirely grass based diet. Plus, all gelada vocalizations are quite different from chacma vocalizations, not just copulation calls. I am normally critical of any hypothesis that argues that baboons are the species of choice for studying social mechanism and hominoid evolutionary biology, and since geladas have become a new standard for studying social cognition, I am skeptical of them as well. Compared to baboons, macaques, and apes, we do not know a great deal about gelada cognition. We just haven't been studying geladas for long enough.

le Roux et al have made a good start. This is "the first study to systematically document tactical deception of a primate living in a natural environment", and the importance of that should not be understated. There are two obvious directions to go from here: fill out our understanding of gelada behavior and replicate this research in other species. The first will happen, it is happening in Ethiopia right now, but it will take a while.

The second is more difficult, but in my personal opinion, more important. Unlike the Ethiopian highlands where "there is simply no place to hide", the Bush or Fynbos, the natural habitat of chacmas, affords plenty of opportunities to copulate in secret. Nevertheless, I am all too aware of how difficult study primate concealment behaviors, for readily apparent reasons. I have heard many extra-pair copulations while among the baboons, but I don't know that I have ever seen one. On the other hand, I wasn't looking for them. I don't think it would be exceptionally difficult to do dedicated full-day follows of each monkey in a pair. Someone just has to do it.

le Roux, A., Snyder-Mackler, N., Roberts, E., Beehner, J., & Bergman, T. (2013). Evidence for tactical concealment in a wild primate Nature Communications, 4 DOI: 10.1038/ncomms2468

I have no idea what's going on

The picture says it all. I've had all these good things to write about come up, and then BOOM this new grant socked me right in the bean machine and my life instantly shattered into little pieces of madness. In short, I have too much stuff to do, and my hands are sore from all the writing.

In truth, the submissive behavior this (zoo) baboon appears to begin by presenting his butt, a standard submissive behavior, but then everything shifts into nightmare world territory when he lifts the leg, starts screaming at the humans, and does the weird hand thing. I've seen the hand thing before, but in macaque monkeys. And its only this one guy in the colony who will sometimes rest his hand near his tail when he is being groomed from behind. He's a bit of a jittery monkey overall, but not totally neurotic; he's much calmer than that baboon is under similar circumstances.

Then again, its also a juvenile, so his behavior is difficult to analyze. There must be something ethologically relevant to "hand-to-butt" behavior, though. I've seen it too many times in too many species. Its related to the presentation behavior, which is in turn derived from the female copulation stance. Females don't have the luxury of being able to scratch their butts during copulation; there's an awful lot of force involved, and the female's frame needs all the support it can get to absorb it all. Where would the added hand gesture have originated? Oh look, I found at least one recent, directly relevant article discussing this subject.

Well look at that, complex thought is still possible in my mind afterall. I'm too curious not to write up a synopsis of these findings regarding the copulation position, and I do have a much needed vacation coming up.

On post-ejaculatory wiping

Stop monkeying around and pass me a leaf

Chimpanzees in Budongo Forest in Uganda regularly employ leaves as 'napkins' to wipe their penis after sex, researchers discovered

The authors of a study called High Frequency of Postcoital Penis Cleaning in Budongo Chimpanzees do not beat about the bush. "We report on postcoital penis cleaning in chimpanzees," they write. "In penis cleaning, leaves are employed as 'napkins' to wipe clean the penis after sex. Alternatively, the same cleaning motion can be done without leaves, simply using the fingers. Not all chimpanzee communities studied across Africa clean their penes and, where documented, the behaviour is rare. By contrast, we identify postcoital penis cleaning in Budongo Forest, Uganda, as customary."

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My first thought: What about masturbation?

The Guardian doesn't mention it at all, but the paper does... once. Its little more than a passing acknowledgement, however, all mentions from there on out are specific to coitus, and the data included in their tables follow suit.

Masturbation is a behavior distinct from copulation. The two end in orgasm for the male, but the resemblances end there. The two activities serve entirely different purposes: coitus is for reproduction and social purposes, masturbation (in males) is for monitoring and controlling ejaculate output.

Which is not to say it is impossible that the two activities could have overlapping purposes. That's where this study starts to come into play, or could come into play. But, the paper chooses not to examine masturbation activities in this context. I'm not sure quite why, to be honest.

Take to the baboons: I've seen them almost always finger clean after they pluck the rooster, but I cannot think of a single copulation which involved cleaning. Granted, copulations are much messier affairs, but its the female who dart after sex. The male generally follows leisurely behind for a few paces, or sits down and starts grunting. That'd be an interesting behavior to compare to across species, and in the case of masturbation, it really should not be difficult at all to gather data.

Unless chimps aren't into jerking off as much as most other social primates. I really think I would have heard about it if that was the case.

A final aside: it would be great to see some, you know, significance statistics for the data in this paper. Otherwise, fun read!

Thanks to Pfeng or Retrochef or whatever she prefers to call herself these days for the tip on this paper.

O’Hara, S., & Lee, P. (2006). High Frequency of Postcoital Penis Cleaning in Budongo Chimpanzees Folia Primatologica, 77 (5), 353-358 DOI: 10.1159/000093700

Sorority?

Last time I promised that I would elaborate on the situation I presented last time, namely, Gertrude and Hilda. To my trained but imperfect human eyes the two look like sisters. As an exercise, let's assume that they are. But if they are, how and why do they appear to differ so greatly in rank?

A few things first. If the two are sisters, they are almost certainly not full sisters, they probably only share one parent. This I shall assume, as males generally do not maintain their rank long enough for a single copulatory pair to make it through two pregnancies. This would also require Gertie and Hilda be born one after the other; there are just too many unlikely aspects to such a setup. Thus we'll assume they shared only one parents, but which parent will prove to be an interesting question.

Sharing a mother between the two sisters is problematic. If this were to be the case, the mother would need to be quite highly ranked, to explain Hilda's own rank. Gertrude's low rank is less of a problem this way - female's can lose a great deal of rank much more easily than they can gain rank. So under this scenario, how does Gertie lose all of her ranks?

Alright, we don't really know enough about Gertrude's rank to say where she's fallen to. Maybe she never really collapsed, maybe she just got super old and couldn't protect herself, or developed some disease which makes her weak. Even though males are the sex whose rank is primarily based on pure strength, and females can rely on the cushion of their matriline, they still need to be able to protect themselves. in truth, Gertie is very seldom bothered by anyone because she stays out of the way and is no longer sexually receptive. In theory she could still hold a high rank, but just doesn't make use of it.

What if they shared the same father? Well, an alpha male is likely to mate with the top rank females, and create progeny of high rank, like Hilda. However, males are never long in the alpha spot. An up and coming male may have joined a troop and impregnated a mid-to-low rank female, and several years later, having risen to alpha status, impregnated a high ranking female who in turn gave birth to Hilda.

On the other hand, a low ranking, but clever male may have regularly mated with low ranked females, but slipped in a few sneaky, extra-pair copulations with a high ranking one, and one such copulation might happened to have yielded a successfully pregnancy. This isn't a terribly likely option, but either scenario would give us Gertrude and Hilda as they are today.

So there you have it, a wealth of different ethologically sound (I swear) explanations for how two old sister baboons ended up in such different places in the autumn of their lives.

They Grow Up So Quick

Previously, I told the story of a young juvenile male who represents a broad swatch of perversion in the baboon population ages 2 to 5. They really like to have sex. However, this epidemic of carnal lust extends into the female domain as well.

Female baboons have it rough. That post focused on the violence against females, and briefly touched on their swellings. Females get their first swellings quite young. The swellings aren't very large, but they're definitely there. What isn't there is the ability to reproduce. They'll wish they could, but it takes more than a year usually for the young females to become fertile. Even then, they'll have quite a bit of trouble finding a decent male to mate with.

These females are barely more than juveniles, are not old enough to be as physically strong as mature females, and just don't have mothering experience. There is a good chance that a female will be impregnated by some low ranking sub-adult male, and first two or three babies will all die in infancy because the female isn't strong or experienced enough. After those first few "trial" runs, they'll start attracting the attention of more worthy mates.

All females go through this phase, but seem just a bit small for those enormous swellings. The running theory is that our baboons mature earlier due to their comparatively high calorie diet. They grow in size much quicker than baboons living in the northern bush, but the accelerated growth might not be fully synchronized with the accelerated sexual development, allowing them to develop swellings when they are younger and smaller.

Summarizing Sapolsky, these females are driven crazy by an overdrive of hormones which they're just getting used to, and the males are no help. The males won't touch the females because they know that the potential is low, so the females get little relief from their torment.

We call these young females Lolitas, after Nabokov's original novel... and perhaps after the following mainstream cultural phenomenon. We all had our own reasons. The females are all small compared to the adult males, or sub-adults for that matter, but the Lolitas are almost inconceivably small. All they need do is hold on for a few more years and then they can mate with real males and have adorable baboons babies that everyone in the troop will line up to grunt to. If they have a decent rank in the hierarchy.

The Cough

At the core of animal behavior is the concept of the Fixed Action Pattern (FAP). They're a basic unit of behavior, which is effectively the same, every time you or your monkey does it. A classic example if the yawn. You can't stop a yawn once it starts, and its pretty much the same deal each time around. Many other simple behaviors are FAPs as well, like a sneeze or a... cough.

And what would this blog be without constant mentions of baboon intercourse? Mating behavior is likely directed by FAPs. The male approaches the female in the same way, each time, the body language is the same, and the ultimate motions are identical. The post-climax period is marked by the female copulation call and dart. The dart and calls vary, with the calls being more robust than the dart.

Any variance is a negative indicator, however. FAPs are supposed to happen the same way, every time. If you try to interrupt a FAP, you generally won't succeed. Possibly the most famous example is from the Graylag Goose, which exhibits an "egg rolling FAP." If a mother spots an egg outside of the nest, she will engage in a distinct rolling behavior with her beak to move the egg back to safety. If you pull the egg out of the environment after initiating the behavior, the mother goose will continue to roll a space of empty air until the behavior is complete. The "egg roll" is also an excellent example of a elaborate, multi-motion FAP.

So, I've had my doubts about the female copulation call being a FAP because it hardly seems to be fixed. Then came the cough. Lottie, top ranked female, queen of the troop, was beginning to swell, but not so much as to attract the attention of Aaron the alpha. Thus, the usual crowd of randy sub-adults were lining up to have a shot at Lottie's reproductive tract. For us researchers, this means that Lottie will be making copulation calls from dawn till dusk for close to a week.

Lottie was firing up for yet another copulation call while two of my colleagues were watching her, taking notes. I was about thirty meters away, and not paying much attention to the scene, since as I've indicated, Lottie copulating is not exactly a big deal.



Above, you can hear an audio sample of a female baboon copulation call (I don't know for certain that this clip is from the the correct species, but it sounds the same as what has been burned into my mind...). Out of all the baboon vocalizations, the copulation call may be the most complex and difficult to reproduce. All the others are short barks or screams, with the possible exception of the male roar-grunt. All the others are quick and easy to miss at a distance, but there is nothing so distinctive as a copulation call.

As you can hear, there are two parts of the call, a rise and a fall. Lottie did fine with the rise part, but when it came to the fall, she got through one "burst" and then broke out into a fit of coughs and spasms. Lottie's must have been hitting the Marlboro's pretty hard. Either that, or hanging around the braai a bit too much.

After spluttering for a couple of seconds, Lottie raised her head, and continued the copulation call.  No amount of fiddling with audio samples could allow me to recreate the seamless sonic amalgamation of the two behaviors.

Nor could Lottie's nonchalance prevent my colleagues from breaking out into raucous laughter at the sight and sounds. If anything, her matter-of-fact approach to the incident enhanced the humor of the event.

Ridiculousness aside, Lottie's mash-up poses some intriguing ethological questions. The copulation call clearly is not a single FAP. Since there appear to be two parts, its quite likely that there are a complex series of FAPs which make up a copulation call. The rise might be a complete, uninterruptable pattern unto itself, and the falls may be short patterns of varying length. There's considerable variation among the falling cries, which could be a problem. Given how Lottie behaved, it could easily be that the latter part of the call is a voluntary, conscious action, since she continued the behavior after it was rudely interrupted by her cough.

These days, isolating what is and isn't a fixed action pattern is not exactly hot game in the animal behavior world. Which is why its fun to have a look on the side of another project, if you have the chance. Ultimately, that might be the best part about doing field primatology: the opportunities to see things that just happen in the course of a day, things you're not looking for and might not expect, but make a big impression when they do occur. Or they make you laugh, which is good too.

Just copulate with me already

Dolly is a little female baboon with a problem. Her problem is that she must suffer through the discomfort of active estrous swellings without being able to reproduce. Something else in her reproductive system isn't quite mature yet, so... no babies for her. This is nothing out of the ordinary; as far as I've been able to discern, all sub-adult females go through a phase such as this before becoming pregnant for the first time. A juvenile female becomes a sub-adult when her first swelling appears, and a full fledged female when she become pregnant. Or gives birth. Baboonists tend to argue about these definitions from time to time.

Unfortunately for Dolly, she tends to be ignored by the prime meat of the troop. This doesn't stop her from trying, however. One particular day, I noticed her hanging around Aaron for nearly an hour, berating him ever couple minutes with the swollen pink flesh of her rear end. He'd just be sitting on a rock, solemnly gazing out across the expanses of his females, and suddenly there would be a bright female butt thrust into his face. If she was lucky, he'd glance at her before returning to his seemingly emotionless survey of the troop. Quite a far cry from a gruntalicious copulation.

But there's always a chance.

Chasing after Aaron is not risk free, however. The adult females, particular the top ranked one, often take great offense at Dolly and young/low ranked females when they attempt to solicit attention from Aaron. Some serious beatings have resulted from young females stepping out of line.

Thus, Dolly makes due with younger males, some of which are smaller than she is. If she's lucky, Janny, one of the sub-adults will take interest in her for a few days, but as soon as a fertile adult female becomes "available" he'll be off to greener pastures with her.

Dolly has an active, if slightly underpowered sex drive and no way to get rid of it (i.e. pregnancy). There's not a lot else to do but obey the urges until her system comes fully online in a year or so and pregnancy hits. Its unclear if the males have any understanding of her infertility. The young guys are still all over her, but then again, they might just be acting out their own sex drives, which as I've established, is quite strong in males at a young age.

There are many other females who Aaron regularly ignores - he sticks to the top 4 or 5 females usually, sometimes even when they're clearly not capable of becoming pregnant: for the first few cycles after giving birth the female's hormones aren't right for reproduction. But Aaron doesn't seem to care, he keeps going at it with Lottie. Why not go after every female possible? He could do it, he's the strongest alpha male in the entire locality, he might have to give up some extra-pair copulations for some of the females, but that'd be a small price.

If Aaron isn't doing it though, he must have a good reason. The subconscious is way smarter than any reasoning can be, after all. Sperm competition and its extremely intricate and complex guidelines (which we only are beginning to understand) indicates a few possibilities, for instance, Aaron wouldn't want to decrease the quality of his sperm balance by rampantly copulating without forethought. Even in the monkey world, you can't just have indiscriminate sex all the time. Paradise can be such a drag.

Friends with benefits

Damian has continued to maintain his unusually good ties with Lauren for the past few months, and this relationship doesn't appear to be dying down anytime soon, if one looks at all the obstacles they've mounted thus far.

Its been found that Damian is not exclusive with Lauren. Recently, another timid young female by the name of Reyna has gone in and out of estrus, and Damian chose to consort with her. Lauren got this time "off," which I first observed when she was scene interacting with other females for the first time in months. One of those situations where you look and think, I don't know that baboon, and then puzzle over it for a few minutes before face-palming over the obvious answer.

Nevertheless, at the end of the affair, Lauren returned to Damian's side. She remains even now, despite the fact that she is clearly pregnant, and Damian has no need to worry about guarding her swelling or her child. He could leave her to her own devices and return later to guard their child, but he keep her exclusive, and the two show no signs of giving up their status as the weird, reclusive couple of the troop.

They would have had some competition for that title, had not a similar turn of events lead the other pair away. Chester, one of the old males (probably the oldest male in the area) has always had a fondness for Eunice, a female of little consequence. Chetser, Eunice, and her baby would often be seen at the periphery, alone, grooming one another and playing with the baby. None of them have been so rigidly withdrawn as Damian and Lauren. Chester is a genial old male, and often has a small pack of infants following him around. He's like the friendly neighborhood grandpa. He's very protective of his playgroup, too.

But, when Chester decides to go for a rest, often he'll go to Eunice and her child and settle down for a nap right next to them.

Similarly, Eunice will actually mingle with the rest of the troop, unlike Lauren. Neither half of this pair is the most social of baboons, but neither are they they the token reclusive couple, ala Damian and Lauren. Then again, there's also Wilhelmina, who is the oldest and shyest female anyone has ever seen. She grunts like a male, her voice is so worn out.

I suppose the child must be Chester's - it seems very strange that Chester would favor this single infant over the others. Perhaps this is what will happen between Damian and Lauren when her child is born.

There is another possibility: Eunice is Chester's daughter. Since females stay in one troop throughout their entire lifetimes, and Chester is old as sin, this is quite reasonable, and the possibility makes incest discussions even more fun. Oooh! Maybe he's the father of both of them. It would be like the baboon version of Chinatown. What I wouldn't give to have full genetic data for these troops.


So Damian and Lauren had their reclusive title locked up pretty securely in the first place, but now its completely inconsequential because Chester, Eunice, and her infant have vanished.

Okay, that's blowing it a bit out of proportion. A couple weeks after Mortimer pulled his stunt, I began to wonder what Chester was up to when I didn't remember seeing him. One morning I received a call from a colleague up the mountain, "I've spotted Chester up with the troop here, and, uh, Eunice is here with her baby as well."

It was odd enough for an old male like Morty to switch it up, but an old guy, his filly, and their young ward? If I were the mother, I'd be pretty afraid for the life of my baby upon entering a foreign troop filled with testosterone bloated males just dying to spread their genes around some more. That's some impressive loyalty to follow your male into the hornet's nest... of other males.

I wish the news had been more surprising, but the funny thing is that this isn't the first time Chester and Eunice have eloped together. The previous occasion was before my time, but I gather it was quite similar. One day, the two of them went off to the second troop and stayed there for about a month. Then they came back. I really hope they come back soon, I miss that old guy already...

On Pubes

While glancing through the Scientific American site the other day while soaking up that article about the fate of the PhD, I saw a link to A Bushel of Facts About the Uniqueness of Human Pubic Hair, and my deeply rooted primatological instincts said, "Oooh pubic hair! You were just thinking about that in the field the other day when Aaron and Janny were copulating like mad! Click it! CLICK IT!"

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A Bushel of Facts About the Uniqueness of Human Pubic Hair

By Jesse Bering

Like many people, I ask myself continuously about some of life’s biggest mysteries. Why are we here? What is the meaning of life? Why do we have those strangely sparse, wiry little hairs growing around our genitals—hair that is singularly different from the all the other hair on our bodies? Fortunately, a group of leading-edge scientists have managed to put my mind to rest on at least one of these daunting existential questions. In recent years, it seems, researchers have made some tremendous advances in the study of pubic hair.

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I didn't regret the click. Actually, I rarely do when my inner chimp speaks up to me in such ways.

Troop Mind Journal 02/09

Aaron was consorting again. When the alpha male is in a consortship with a female, things tend to get (more) boring because the male will just follow her bobbing bum around all day, rather than using his masculine influence to drive the troops behavior towards goals... or rather, other goals.

This thought crossed my mind, and next I began to think, well, if the male is such a powerful force in the troop mind, then what happens if he appears to not be exerting his influence on the greater mentality?

This is essentially the situation you're given when a male is indisposed due to the influence of feminine wiles. The troop acts independently of the male since he's just bowing to the whims of his girlfriend. Right?

As I observed, greater complexities began to emerge before me. It is true that Aaron was just following the estrous female, Siri, as far as I could make out. He remained with her at the rear-center of the group, and left the juvenile and sub-adult males to seek out the feeding ground via the usual routes.

What was Siri following? Normally she'd tag along with the core of females, which generally followed Aaron's lead by several meters. Without his lead, what influenced her motions? Ultimately it seemed like she followed the lead of the males up front.

Yet the most telling scene of this day came in the early morning, just after the baboons woke up from their night's sleep. As usual, they groomed and played around their bedspots for an hour or so before beginning to move. Longer, today, because Aaron was leading the departure.

Aaron and Siri spent the morning quite actively. They were copulating, of course, and Siri was leading Aaron, and the two of them moved back and forth between the eastern to western boundaries of the sleeping site. This pattern continued without fail until the group finally left. The pair were able to complete three cycles of west-to-east-back-to-west in a little more than an hour.

Here's where the situation becomes intriguing: the rest of the troops' movements mirrored those of the copulating pair, but lagged behind by about ten minutes or so. It was like waves of water washing up along the sides of a half-pipe: Aaron and Siri represented by the tip of each wave, followed by the body of the wave, the bulk of the troop.

In particular, the other females followed the pair, presumably still following Aaron's movements. He wasn't going very far, the span between the two edges was a hundred meters at most, but the vast majority of the females, and many of the juveniles followed in his wake. In spite of Aaron's clearly altered behavior, the troop was still heavily influenced by his relatively small movements. Aaron and Siri sit at the far western side, and twenty minutes later, they would be headed back from whence they came, but Lottie, Matilda, Punzle, Wendy, and company would be sitting and grooming where Aaron had been a few minutes earlier.

When the male posse did manage to get out the door, it was unclear if Siri or Aaron was the member of the pair to follow. Aaron was behind her, but that actually says almost nothing, since a male baboon moving behind a female, no matter how calm, could be a follow or herd. Still, where the pair went, the core followed after.

One must ask again, what was leading Siri that morning? Coyness with Aaron? Legitimate desire to get away from him? Youthful energy (she has yet to have a baby of her own)? Was it the simple by product of the standard copulatory dart, whereby the female runs a short distance away each time the male mates with her? Under the blade of Occam's Razor, we might find that was all there was to it.

Misdirected Affection

In the continuing vein of "silly things baboons do around humans," I have another story about one of young tykes. But first a quick bit on instruction in the multifunctional rear end of the monkey.

Old world monkeys, including baboons, have these prominant hard spots on their butts called callosities. They're good for sitting on because they're basically what they sound like - giant calluses.

The butt is also known for the swellings which are these grotesque pink balloons that tell you when an female is ready for plunder. Well not you I hope, but the males. The females will often times dash up to the males and stick their behinds to in the males' faces, thus "presenting" the goods, in hopes of getting a quickie (the young females particularly like to do this because they are really desperate and none of the adult males want to have sex with them). Hence the term presentation hold a major place in our vocabulary as primatologists.

Over the years, species have come and gone, and presentation has become both a functional and ritualistic behavior. From yielding to the reproductive designs of the males, the behavior has taken on larger dominance/submissiveness connotations, so that presentation (and beyond that, mounting) becomes a sign of dominance removed from any actual intercourse. The adult females out of estrus do it, the males do it to one another, and the young juveniles and infants do it.

The last category is relevant to today's misadventure. I was chilling out with the usual pack of jokers, also know as the juveniles. They appeared to be interested in initiating one of the black infants, at that moment. They'd probably lose interest in about 10 minutes. Young playing baboons aren't exactly well-known for their attention spans.

Aforementioned "blackie" (as the young black infants are affectionately referred to) slowly began to approach my position, while I was none the wiser. I was a fair distance away, taking a breather, propped against a dead log. I took notice when the sprog bounded up to me like an excitedly puppy. She looked at me for a bit. I looked back, suspiciously. I looked around for the mother or some larger protecting male. Getting up might scare her, which wouldn't help me in my predicament at all.

The staring contest was cut short when the blackie took action. She awkwardly leaped up into the air, spun around, and landed, her backside fully presented to me.

I continued to stare in some amazement. As if to say, "I don't think you understood me, let me show you again," she returned to her original position, and then performed the same awkward flip into presentation. She repeated the acrobatic sequence a couple more times.

To be entirely honest, I was quite flattered. It was quite adorable to have a baby baboon display its submissiveness to me. The energy it put into the behavior was refreshing as well. She seemed all too happy to recognize me as being above her in the hierarchy.

That's probably nicest part about this - a feeling of inclusion is very difficult to obtain around baboons When they grow older than a year, and they notice you near by, the juveniles just stare at you like you're some kind of alien visitor from another planet. The youngest of the infants don't have brains developed enough to tell us apart from their own species. Or at least they're just confused enough to think us worthy the effort. This one was older, so she might have just been practicing on me, though that would require a complicated mental state that I'm not sure any baboon possesses. Either way, my own perception of the situation, correct or not, played an equally important role in the magic of the moment.

Wars and Alliances

Some mouse sperm can identify, and even cooperate with, its brethren

ScienceDaily (2010-01-25) -- Some mouse sperm can discriminate between its brethren and competing sperm from other males, clustering with its closest relatives to swim faster in the race to the egg. But this sort of cooperation appears to be present only in certain promiscuous species, where it affords an individual's sperm a competitive advantage over that of other males. ... > read full article

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Back in the day I wrote a diddy on Sperm Warfare, which is a sweet book worth reading. It is also a controversial book, and the results have been challenged in the years since its publication. However, as one famous but egotistically arrogant professor told me, "don't believe any results until at least five different labs replicate the findings."

Which brings us to today's news item: more support for the idea that sperm are highly adaptable, multipurpose creations. For some time, it was believed that a large portion of sperm were not viable, thus not functional. Sociobiologically, something sounds wrong with this statement. Evolution doesn't waste such an important commodity.

Some truly wasted sperm are bound to be malformed, but not a significant number. Sperm Wars (and the research behind the book) suggests that there are many varieties of sperm, all of which are functional in their own way. Inseminators, warriors, blockers, and now cooperators. If sperm are shown to be doing something adaptive, then chances are this isn't going to be an isolated example.

The authors of the paper mention that most human sperm do not possess the necessary head shape to facilitate cooperative clustering. Human sperm is known for quite high variability, however, so I wouldn't rule out the possibility just yet. Again, at least five labs ought to reproduce the data. Plus, this could catch on in humans any day now.

Sperm competition is the counter to female cryptic choice, another devious reproductive tactics. Sperm Wars received considerable flak because the subject material is frankly disturbing, largely because it talks about the adaptability of infidelity. As with Wilson's original Sociobiology, it the book did not support any such actions. The fair view is to recognize the utility of all major strategies, paying due homage to the monogamous family which dominates human bonding.

Being a female baboon is not a fun time

 The title says it all. All that's left for me to do is tell you how through the use of shocking anecdotes.

One of my colleagues and I were able to sum up the difference between the genders quite concisely. We approached the divide on the plane of physical appearance, since is this one of the realms in which we humans are best able to understand baboons.

Male baboons are greatly fortunate in being very handsome. They are blessed with thick, flowing coats of hair, square jaws, pristine bodies, and ears which are usually entirely intact. The females have misshapen nipples, scarred tails, mangled finger permanently bent out of shape, and ears which are often so damaged they become our primary means of identification. Furthermore, when a female is frightened, her tail sticks into the air, her lips curl back revealing her yellow teeth and bright pink gums, and she dashes about wailing frantically. It is a hideous sight to behold.

Please do not get the wrong impression - I do not fault the females, for how can I? Most of their unattractiveness is caused by baboon-on-baboon violence, not innate uglyiness. Everyone beats up on female baboons. From a human standpoint, they were dealt a very poor hand, indeed.

The most obvious (to us humans) source of violence is the males. Our minds are swamped with tales of domestic violence in human society, offering us some preparation for what we observe in the troops. Adult male baboons always sit much higher in the absolute hierarchy than females, mostly because of their immense size advantage. This size is exactly what defines much of their relationship with the females. Virtually all adult males, not just the alpha, will chase the females. We call this herding. Males use it as a tactic to control the movements and interactions of females - the unfortunate victim of the herding, specifically, but also any other females in the vicinity.

Most of the time, the chased female will just grimace and shriek horribly while running madly from the male, but the male can pretty much always catch the female if he truly desires. Maybe he's really angry at that female, or displacing some other aggression, but there are times when he catches, them, and its not a pretty site. The effect on the female is primarily mental and emotional, nevertheless the females rarely escape physical harm.

Like their brothers, juveniles will also chase the females around. An adult female is about the same size as a four year old juvenile, and the females are not built for rigorous combat. So, those juveniles can push them around just as easily. Injury is rarely incurred by the females in these conflicts, but I can personally attest that these males tend to be huge assholes, and are a giant nuisance to constantly deal with.

Yet, a female's worst injuries are invariably inflicted by other female baboons.

A female's time is largely consumed with socializing with other females, and the young children. The dominance hierarchy is thus very important to these female baboons, as it affects mate selection, alliances, grooming partners, etc. Basically, baboons hierarchies are rigid. Part of why they are so rigid is because is you step out of line, you'll end up starting a fight. The torn ears, ragged tails, and scratched faces are the obvious signs of the lifelong sources of suffering

Males leap about, wahoo at each other, engaging in ritualized aggression, which is when the fighting doesn't actually come to blows, but one's strength is displayed via alternative methods. In the case of the male baboons, they engage in "wahoo battle" where the male who can run around and shout at the top of his longs the longest is clearly shown to be the strongest. This way, no one gets hurt, which is good for everyone, and the outcome remains the same. From my observations, it appears that females engage in a lot less ritual aggression, and a lot more real aggression

I have seen female baboons gradually tear the skin from the skull bone of a live and struggling female over the course of several days (a tale which may one day be told in full...). She lived, but her scars will not fade anytime soon.

Violence appears to be the worst part of a female baboon's life. Still, when they aren't being abused, they still have to to deal with the joys of pregnancy and subsequent high infant mortality rates. There's no such thing as monkey abstinence, so until they become menopausal, female is either pregnant or suckling some brat who is constantly yanking on their nipples (when I am able to get a good shot of this, I will show you these nipples - they are impressive). They're often still suckling when they begin cycling again, which doesn't stop the males from following them around all day, and copulating on a whim. Immediately following ovulation, I'd guess a female will have to copulate about a hundred times in a day. Plus, they have to carry those big, tender genital swellings around all day.

Its hard to think of upsides, though I am a male, so I am unfortunately not the best judge. The juveniles are really the ones who have it easy. Females have all the problems I've just stated, and the males barely live past ten years, and their lives are honestly pretty dull most hours of the day. If you're ever reincarnated as a baboon, choose to be juvenile... And then never grow up. I did a search for "Peter Pan Baboon" and couldn't find any remotely relevant images, so I think I'm done here.

Remembrance of Things Past

I've been sick this week, so I decided to bring back and expand an old story which I feel really deserves its own entry. Also someone mentioned something about this being "the place to go for monkey sex stories" or something like that, and I hate to disappoint.

This day in the field had been a trying one already. Twas Friday, and far past noon, the two key ingredients in an itis inducing recipe for fatigue. We had just followed the troop into a bush and tree filled ravine less than an hour earlier. The bushes often stood well over our heads, and some of them were thorny to boot. Visibility and comfort were at a minimum. But, we decided to tough it out in hopes that the monkeys would stop here only briefly, and soon pass on.

Our gamble was lost. The baboons decided to enter the ravine for feeding purposes, and when they feed they can stay for quite a while. We didn't know this at the time, so we just followed them around while they moved back and forth in the tiny valley.

I took a break from this chase, exhausted, and sat down on a large fallen log. I had chosen the spot because it was surrounded on three sides, and out of the way of the baboons. In the dense bushes, one had to keep moving and be constantly vigilant of baboons ahead and behind. Generally, there was one route from place to place within the ravine, so a small appendix jutting off the intestine of the main route was a relief to find.

Let me tell you a thing or two about how the baboons were feeling on this day. The most notable detail was that Nadine was in estrus, and as the second ranking female, Aaron was highly absorbed in her movements, particularly those of her butt. This had been going on for a couple of days, and the two had been mostly inseparable. However, when the troop enters just such a mess of tangles and vines, if two baboons become separated, it can be quite difficult to reconnect, especially if one of them doesn't want to be found.

Just such a situation had developed between Aaron and Nadine, while I sat for a few minutes on that log. Nadine came strolling around the corner (i.e. a tree) and stepped onto the log about ten meters away. She sat.

From out of nowhere, Grandpa Bertrand came swaggering towards her. She remained immobile. His bulky coat whirling, he deftly pulled around behind her. At this, she rose and began walking briskly towards me. Bertrand followed, outpacing her, rapidly closing the meter between them. Nadine was now five meters away from me. Three. One.

Impact. Betrand reached out, grabbed her, slid his feet onto her calves, and fired up the plunger.

About five seconds later, Nadine erupted with a "urrrh......urrh......urrh......urrh...urrh...urrh...urrh... urrhurrhurrhurrhurrhurrhurrhurrhurrh......... uuurrrrhh......... uuurrrrhh......... uuurrrrhh" and darted away from Bertrand, breathing laboriously. Its, um... hard to represent a female copulation call onomatopoetically. And I couldn't find anything on youtube, sorry. Researchers like me write whole papers about this stuff, though.

Bertrand plopped down and grunted a few times, and sat down, excess semen plopping from his glans to the surface of the log, about a foot from where I sat. Bertrand looked around for a few moments, I swear he allowed himself an expression of self-satisfaction. The baboon rose again and sauntered into a thicket after about ten more seconds.

Moments later, Aaron bounded around the bend, intensely examining the scene of the crime. His eyes were alight in that special Aaron way. It was just him and me in that small clearing. "Don't look at me, dude," I held up my hands innocently. "I think you understand that there's no way that I was the one who did that..."

Aaron calmed down quite quickly, and sat himself on a rock about ten meters away, readpoting his characteristic impassive poker-face. "You messed up this time, buddy. There's nothing to do now but learn from your error."

A lot of baboon life comes off as "nothing to do but learn what not to do next time." A mother is too lenient with her baby, it walks too far on a tree branch, slips, and falls to its death? Oh well, be more protective of your next baby. A juvenile plays too exuberantly with a baby and the mother's family all rush in to shriek at him with those awful wails? Be more careful of how rough your play is, and who you choose to play with. An alpha male is not vigilant enough of his prize female when she is in estrous and some joker slips in an extra-pair copulation? Tough luck, guard her zealously on her next cycle. A study of different aspects of baboon memory could be fascinating indeed.


In the end, the troop retreated from the ravine... back up the slope to exactly were they had come from. Our tracking adventure had been in vain. It was one of "those" Fridays. You know, the kind where you just thank the powers that you didn't get trampled by an orgasm addled baboon. We all have those days.

EDIT: I found this article while searching for baboon copulation calls. Its an accessible read, and the guy has his sociobiology down pretty nicely.

They Grow Up So Fast

I was confronted with a startling scene recently. We researchers gradually become dulled to the violent and melodramatic lives of monkeys. Yet, there are still little moments when we are momentarily taken over by human partiality, and are surprised.

On this day, I watched in amazement as a juvenile male baboon mounted a receptive adult female, and began to have sex with her.

When baboons copulate, the male will almost always stand on the back legs of the female, his foot cradled in her knee joint, like so:

Unless the male is a really meaty boy, the female is a Lolita, and the dude's feet can thus reach all the way to the ground, they will always copulate in this position. And they'll try their darnedest to follow protocol, no matter what.

Take my little tyke for example. He was probably less than 2 year old. He looked old enough to still be suckling; I wouldn't have been surprised if after he did the dirty deed he ran back for a quick nip of milk to get his strength back.

This guy is struggling for all his worth to get up onto those knee-pits, but for the life of him, he could only manage one leg. So he made the most of the deal and began thrusting madly... successfully impregnating the vast span of air between the adult female's vulva and his undersized phallus. Its all for the best, as there is a good chance that this female was an aunt or grandmother.

They start young, there's no denying that.

Damian's Pitch

There is a young adult male in the main troop named Damian - this is to say he is not a sub-adult, because he copulates with adult females, can vocalize full wahoo's, and most importantly, he wasn't born in the troop, he came from the outside. Damian is still a bit slim,  having yet to fill out his fluff like the more ripe adult males. This shouldn't fool you; he's not one to mess with.

Damian possesses strong aloofness: he sits away from the rest of the troop much of the time and doesn't deign to involve himself in the affairs of the everyday troop melodrama. Yet, one still finds him with occasional wounds no doubt obtained during heated male-on-male action. Bertrand and Chester have a lot of weight to throw around, but they are unquestionably the past; Aaron is unequivocal alpha. Aaron is not as spry as we once believed, however. Damian is image of the troop's future.

For some time, I felt that it was inevitable that Damian would usurp Aaron's position, probably during my stay here. Lately, a different strategy has emerged, and may remove any need for Aaron and Damian to battle over the coveted top slot.

Some time in the past few months, Damian took a liking to an unremarkable female named Lauren. It began with a standard consortship. Damian would follow Lauren's swollen rear-end through wood and bush, copulating to his heart's content. Usually a consortship lasts a few days, when the female's swelling is at its peak and the allure of the estrous aroma is irresistible. Damian's consortship persisted long after her swelling had begun to deflate... and just kept going.

The two are constant companions now. She has joined him in his little world away from the rest of the group. Recently a sub-adult female has joined them which is good for Lauren, otherwise she would have no social life. I've seen a couple other females visiting Damian on the outskirts, but none of the other adult females have joined his harem, yet.

This doesn't appear to be a typical strategy, as far as I'm aware. There are stories of how a big male once pulled away seven or eight females from a huge troop and started his own, mini-troop. This could be Damian's long term plan. In the meantime, he's yet to annoy Aaron past the point of no return.

Perhaps Damian is attempting to gather support, and once he has enough females backing him, he'll attempt to overthrow Aaron. I've not heard of such complexity in baboon social affairs. Usually, a new male will just fight with the old alpha until he wins or dies. Maybe Damian just doesn't care for society. He has a brooding look about him, accentuated by his thick mane of long black hair and missing right eye. He's isolated from support, but still not someone you would ever want to mess with. I think I've seen him get into a tussle with another adult only a couple of times. He's your token dark and mysterious guy.

What's in it for the females? Well, Damian basically gives exclusive attention to his entourage, and does not need to divide himself between 20 others like an alpha would. I have heard of this strategy, which basically amounts to what we humans would call "being a good father." Lauren has yet to bear Damian's child, however, so I can't pass judgment on how strong his paternal instinct is.

Taking the question further, why Lauren? What about this particular female made her follow Damian, and why did Damian choose her? Did she have little choice in the matter? Did Damian have little choice, taking whatever he could get?

At this point, the questions replicate upon themselves ad infinitum. I'll just have to keep observing and hope I see what happens, and then if I do see it, hope that I can understand the monkeys' subtleties.

Map and Maze Puzzles

This past weekend was the annual MIT Mystery Hunt, and every year I say that I'm just not going to care that much, and when the hunt actually starts, I reneg on everything I've said and go peddle to the metal. Of course, I then forget this change of mind a year later and it all happens again. The exception was the 2008 hunt, which actually sucked enough for me not to do any meaningful work for it - I can't remember working on a single puzzle from that year.

This year was not an exception to the pattern, which is unfortunate since I am in Africa and remote solving from a netbook over a crappy ADSL connection is extremely frustrating. Plus I'm unable to access most of the puzzles. In spite of this, I've done what I seem to be a satisfactory amount of work and solving. Which is why I can now divert my attention to writing this post which I have been thinking about for a little while.

In the realm of puzzles, some people are specialists. There are the crossword freaks, sudoku nerds, anagram weirdos, cryptic punks to name a few. I'm a map puzzle specialist, as it turns out, and its generally my opinion that way too few people appreciate a good map puzzle. Consider the atrocities and monstrosities I've had to put up with in previous hunts.

My predilection towards map puzzles is a curious thing. One could easily attribute such a strength to one's puzzle upbringing; the title of this post is taken from the puzzle book which is my traditional all-time favorite (it is sort of like a little hunt unto itself, made up entirely of this sort of puzzle and without any need for the internet), thus we can surmise that my library was at least partially an influence.

However, in 9.10 - Cognitive Neuroscience, we spent a class discussion gender difference in cognitive capacities, which was the first time I encountered the literature behind such stipulations. Gender differences are everywhere in the brain, but what I found intriguing were the differences in spatial ability between the sexes. I dug up an old meta-analysis (Linn and Peterson, 1985) of various spatial tests to have a look at just what the data says.

I do mean, old, too - the review is from 25 years ago and more recent analyses have been published. However, publications in purist psychology journals tend to be more resistant to the Open Access revolution, so I couldn't obtain anything more current. This is unfortunate because I don't like this paper too much - its geared towards developmentalists, not... genderists? Sexists? In particular, it provides only a couple of highly lacking tables and figures for the gender comparison data, placing unwarranted emphasis on the age data. The name of your article is "Emergence and Characterization of Sex Differences in Spatial Ability..." Come on.

So, how does one approach evaluate an individuals ability to think spatially? Traditionally, there are different tests for the tree main types of spatial ability.

Rotational analysis refers to ones ability to visualize 3D objects and rotate them around and accurately revisualize them. This is the kind of skill one would find useful in games like Homeworld or X-Wing, and probably general path-finding.

Very simply put, spatial visualization requires one take an image and alter it, usually in a fairly complex way, following multiple steps.

The bottom line:

Males are significantly better at mental rotation and in spatial perception, females are slightly more able than males at age 4, but at age 5 male ability accelerates and by adulthood, males well-outperform females. In spatial visualization, tests have not revealed significant differences.

I am inclined to attribute map puzzle skill to the one's ability in spatial visualization, due to the highly complex nature of both tasks. This would imply that gender has nothing to do with the matter, which doesn't exactly jive with the stereotypes. Gender stereotypes and bad and all, though usually contain a kernel of truth somewhere within. A small array of tests as we have examined only provides so much information on the big picture of how the brain processes spatial info across the genders. Map and maze puzzles themselves come in all shapes and sizes, thus further obscuring the question.

Which is why the real moral of this post is that one should not too earnestly mix sleep deprived marathon puzzling orgies with stuffy science literature.

Now that the males have a step up at least in the majority of spatial cognition, I'll have to eventually write a counterpoint to level the playing field with the females. Perhaps I'll write about that infuriating female aptitude for multitasking, which is very real. Be afraid.


References:
1. Emergence and Characterization of Sex Differences in Spatial Ability: A Meta-Analysis. Marcia C. Linn, Anne C. Petersen. Child Development, Vol. 56, No. 6 (Dec., 1985), pp. 1479-1498.

Mortimer the Midlife Crisis Male

I don't visit the second troop very often, but over the course of my visits I have been more and more struck by the behavior of a grizzled male called Mortimer.

Senior males cannot be described as typical because outside of the Cape Peninsula, they are quite rare. The life of a male is short and violent. My guys lead violent lives to be sure, but they are not all that short because there are no predators to pick them off after they are injured in a fight. Thus, we have a unique culture of older males in these troops.

Mortimer is certainly not young. I say this because he is missing all of his canine teeth. Baboons are not carnivorous, so their canines only get use in heated brawls. Over the years, you'll see the massive canines yellow and chip away. I don't know if they fall out from the accumulated strain or have to be broken out by a traumatic event because this kind of thing can only happen four times in a male's lifetime, and they fight far too often for me to be able to pick out the moment when a baboon loses a coveted fang.

Morty also has the big coat and deeply lined muzzle of an elderly baboon. Though, his coat isn't a massive ball of shag like that of Chester. We debate over just how old Mortimer is, since he looks old but exhibits youthful behavior which I shall describe.

When a foreign troop can be heard (often through wahoos) nearby, the sub-adults of a troop will often edge to the periphery of their troop, in the direction of the offensive sounds. Male baboons inevitably "disperse" when they come of age. In order to preserve the flow of genes and reduce incest, young adult males will change troops. When males this age skirt to the edge of their own troop, they might be seeking any and all information that can be gleaned about the territory and behavior of the neighboring troops... one of which they will go on to join.

The funny thing is, Mortimer engages in this behavior as well. When the sub-adults wander towards the adjacent troop, Mortimer is commonly found at the front of the bunch, keenly interested in the prospects afforded by other troops.

To my knowledge, there are no studies which describe dispersing fully adult males. Once a male joins a new troop, it is assumed he will stay there for life. Yet, Mort acts like a sub-adult, getting into fights, acting aloof, showing interest in other troops. The key difference is that he is larger and much more experienced that the sub-adults of his troop. If he is on the young side, as some believe, then maybe he's in a bad position, for the alpha male of the troop is a commanding individual. Mortimer is no wimp of a baboon, so perhaps he has some virility left in him and wishes to have the chance to use that fire before it goes out.