On Prairie Dogs

Not exactly my model species, but I talked about birds a short while ago, so why not prairie dogs? They're at least mammals with strong social organization. Anyway, I paper came to my attention, about dispersal in prairie dogs, and it was published in Science, so of course I had to read it.

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Prairie dogs disperse when all close kin have disappeared

Prairie dogs pull up stakes and look for a new place to live when all their close kin have disappeared from their home territory--a striking pattern of dispersal that has not been observed for any other species.

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Original article is here (behind Science's paywall). As previously discussed, baboons disperse when they are on cusp of full adulthood. They find a new troop, and usually stay with that troop until they die.

Prairie dogs differ from baboons in several striking ways. They live in large groups, called colonies, and the size of these groups can vary quite a bit, which is nothing unusual to a primatologist. But unlike baboons, prairie dop groups can range from five to thousands. Colonies can be further subdivided, into wards, and then coteries. Needless to say, prairie dogs almost certainly do not possess baboons' rich understand of who's who in the group. Nevertheless, these subdivisions are oddly reminiscent of the four-level hierarchy found in Hamadryas baboons.

Coteries are the closest thing there is a basic unit of prairie dogs. Coteries are sort of like harems: they consist of a male, several females, plus juveniles and infants. The juvenile males disperse soon after they are a year old. They leave their natal territory, settling about 1.5 miles away, on average. Females tend to stay put.

The author of this paper, Hoogland, references the esteemed Hamilton and May. Their theory was that dispersal occurs because reducing the amount of competition (for mates, food, etc) between related individuals is good for inclusive fitness. On the other hand, the potential for cooperation between related individuals might outweigh the costs of competition. Over the past few decades, Hamilton and May have been supported by findings in the field.

Hoogland has found contradictory evidence in his prairie dogs. When zero relatives are around, females are much more likely to disperse, 2.5 to 12.5 times more likely.

These prairie dogs have no opportunities for competition between relatives, but also no opportunities for familial cooperation. You might think that the dangers of dispersal would still be a major impediment, but apparently these populations live pretty close together, and the females usually just move one colony over, so the risks are low.

Hoogland's own words, to sum it all up:

"The absence of close kin in the natal territory is thus a proximate cause of natal dispersal by prairie dogs, but the ultimate cause is presumably the opportunity to find either a new territory that offers the benefits of cooperation with close kin that dispersed there previously (rare), or a new territory in which survivorship and reproductive success might be less dependent on cooperation with close kin (common)."

This may not be a study about primates, but the laws of dispersal and inclusive fitness govern all animals. When we discover a behavior violates our conceptions about how life must act in order to maximize fitness, there are two main possibilities:

1. The environment that this species lives in has given rise to a different approach to the challenge; unusual local factors are altering behaviors on the fringe.
2. The foundations of the behavior are not what we think they are. There are factors not being considered, which are crucial to understanding why these behaviors happen. Just because our model is correct most of the time, doesn't mean the model accurately represents why animals behave the way they do, in this case.

And anyone seriously studying this stuff ought to pause and consider new evidence in this light, if only briefly. In this case, the first option is probably at work. Prairie dogs are mammals, not so different from primates, but as Hoogland states, this is the first evidence of its kind, irrespective of species. Who knows, maybe a re-examination of dispersal behavior in primates will find similar evidence that's been overlooked. If you find it, chances are you'll get it published in Nature or Science.

Hoogland, J. (2013). Prairie Dogs Disperse When All Close Kin Have Disappeared Science, 339 (6124), 1205-1207 DOI: 10.1126/science.1231689

They All Look The Same

A few weeks have passed since Iran claimed to have sent a monkey to space and back. It did not take long for skeptics to point out that the two monkeys look nothing alike. I can't begin to explain why Iran wouldn't do a better job staging their publicity photographs. My mind has been occupied with (in my opinion) a more interesting question: Why is it easy to distinguish between individuals of some primate species, but not others?

I've spent time with a number of primate species, but in terms of sheer hours of exposure, chacma baboons and rhesus macaques take the top two slots. I know both these species very well. Yet, rhesus macaques are easy for me to distinguish between, while chacma baboons are exceptionally difficult to identify. After spending a few hours with some macaques, I can reliably tell you their name and personality, mostly from looking at their faces. After spending hundreds of hours with the same baboons, I could not tell them apart, at least not based on their faces. They really do all look the same. Its more effective to look at the pattern of tears on their ears, and the shape of the callosities on their rumps. Its quite humbling, actually.

A similar phenomena exists in humans, known as the Cross-Race Effect. Or, as the All Look Same effect. In humans, the difference is based on race, but its not racism. How much of the effect can be explained by nature versus nurture is a matter of contention, but has everything to do with an individual's upbringing, who the individual spends time around as they grow up.

The monkey face recognition effect must be different because I didn't grow up spending large amounts of time around rhesus monkeys. So, I turned to genetic diversity for ideas. The more diverse a species is, the easier it should be to identify within the species. It stands to reason that the species which is much easier to identify (rhesus macaques) would have higher genetic diversity.

Research started off easy. The rhesus macaque is three times as diverse but more closely equivalent in damaging coding variation as compared to the human. That is about as straight forward an answer as I have ever seen in the title of an academic publication. Okay, so what about chacma baboons?

Baboon diversity is not as well understood. Rhesus monkeys are widespread, plus they're the animal of choice when it comes to biomedical research. Baboons are also widespread, and favorites of field researchers. But you don't see them as much in labs, so genetic testing is not a routine procedure. Nonetheless, I found an article which addresses my questions.

Quantifying diversity is a not a simple matter. From data collection to bio-informatic analysis, it can be a bumpy road. I don't know why exactly Newman et al. chose to quantify diversity with the mean percent pairwise difference in haplotypes, but it happens to be pretty easy to explain. To use the metric, you take your data, a set of DNA samples from individual monkeys, and compare each individual's DNA to everyone else's within the same species. You count the number of differences  observed between individual base pairs at the same places in the DNA sequences. Then, convert that number into a percentage, and finally, average all of the comparisons between individuals. That's the author's measure of within species diversity.

The diversity found in rhesus macaques was 4.2%. In chacma baboons, it was 0.9%. That is a considerable difference. These numbers are only given a small mention in this part of the paper, so I don't know the margins of error. Nevertheless, these finding support the hypothesis that baboons are harder to distinguish because there is really is less distinguishing information available; less diversity within the species.

However, there are some extenuating circumstances. The baboons I interact with in Cape Town are from a small population, in fact, a subspecies of chacma baboon, Papio ursinus ursinus. Now their diversity is cut down even further, possibly by an order of magnitude or more.

Most of the rhesus macaques I've spent time with were in captive colonies. There are many rhesus sub-species; no one knows the pedigree of colony monkeys, another dirty secret of the biomedical community. But, my best guess is that they came from rhesus populations as wide spread as you can imagine, so the diversity in colonies is likely to approach 4.2%. I have interacted with wild groups of rhesus macaques, but only for short periods (hours), not for months as I have with the baboons. Are they more difficult to identify than the captive monkeys I know? Yes, they are, but not as difficult as wild baboons.

Which raises a follow-up question: What is the right way to quantify how easy it is to tell members of a species or sub-species apart? My gut feelings aren't going to hold up under scrutiny. Appropriate paradigms already exist: show people (or monkeys) a series of faces, some new some repeated, and ask them if they've seen each one before. As I've heard many Professors say (to myself and others around me), "you could get a thesis out of these experiments."

Yuan, Q., Zhou, Z., Lindell, S., Higley, J., Ferguson, B., Thompson, R., Lopez, J., Suomi, S., Baghal, B., Baker, M., Mash, D., Barr, C., & Goldman, D. (2012). The rhesus macaque is three times as diverse but more closely equivalent in damaging coding variation as compared to the human BMC Genetics, 13 (1) DOI: 10.1186/1471-2156-13-52
Newman, T., Jolly, C., & Rogers, J. (2004). Mitochondrial phylogeny and systematics of baboons (Papio) American Journal of Physical Anthropology, 124 (1), 17-27 DOI: 10.1002/ajpa.10340

More Latest Stuffs on Altruism

At the time, I didn't write much about the Martin Nowab et al. paper which appeared in Nature about a year back, but it generated a bunch a hubbub mostly because everyone thought they were completely wrong.

I thought they were completely wrong, initially. Kin Selection is a wonderfully simple and elegant concept, that is honestly hard to imagine as possibly being wrong. Its too simple and fundamental. I also didn't want it to be wrong because it underlies many of my own core beliefs and personal theories (yes I admit I am allowing my confirmation bias to work here).

In all fairness, I still think they are wrong. I looked around in the months after the initial release, and was satisfied by the refutations from everyone else in the community.

Somehow, the topic came up again more recently and I went back to the original paper. I checked the supplementary materials, unsure if I had looked at them the first time.

I had not. They are almost an entirely new and different paper from the one that actually appears in print. I considered going through this monster 40+ page adversary and critiquing it page by page, but that seemed like it might become a full-time job for a few months, what with having to relearn all of Nowak's obscure mathematical presentations.

Then another article appeared in Science, about ROBOTS and simulations of kin selection in those models. Good read. Yet, Nowak's comment at the end reignited my ire. In orther sources, Nowak says that the critics aren't really going through all of their arguments no matter how many hundreds of scientists print that they're wrong. Its like he's some kind of avate-garde hipster scientist.

Truth be told, I really didn't want to be the one to "go through all their arguments," and very fortunately, someone else came close enough for my tastes, just recently, too.

Rousset and Leon actually tear away at the paper and its supplements, and, because their commentary was not published in Nature like that giant series from March, they can make some much needed criticisms of this article in context.

"The format of the paper itself is an obstacle to scientific communication. The article has two parts: a short illustrated essay for the general reader and a 43-page online mathematical Appendix. Readers who are not mathematically inclined or simply short on time may be tempted to simply trust the authors and gauge the scientific value of the paper based on the ‘weight’ of the supplementary material or on the prestige of the authors."

Thank you, Rousset and Leon. Regardless of the validity of the results, the paper's presentation is a travesty; a travesty that the authors were fully aware of. Devastating stuff, and I really hope everyone involved or even watching has learned a constructive lesson or two from this catastrophe. Now hopefully I can be satisfied that Nowak et al. have been properly refuted.


Rousset F, & Lion S (2011). Much ado about nothing: Nowak et al.'s charge against inclusive fitness theory. Journal of evolutionary biology PMID: 21457170

Queen me?

I'm in the process of writing a paper concerning the ecology and industry of American bison (meat), so my writing engine is low on fuel.

But, a friend sent me this article about bees that I have found myself suprisingly pleased with. Sure, its about insects, but for someone who doesn't spend much time reading entomology papers, it can be rather refreshing. Plus, I would not dream of understating the importance of entomology to the development of the fields of ethology and sociobiology. The fact that I learned about the paper via theNewScientist is less forgivable.

I honestly had no idea how Queens became differetiated from other bees, we just didn't even get into it in Animal Behavior, other than a brief discussion of "royal jelly" which came across almost as an old wives' tale. These folks are lucky that they found such a clear effect from a single compound. A single author, too... most impressive. So, how do Queens come to be in ants, termites, and other eusocial insects?

Anyway, there's your dose of 'real' ethology; the only one you'll get from me for the foreseeable future.

Fake Genetics

I try not to let this blog deteriorate into place I would splatter with arbitrary links, but this one is deserving, particularly because of the conversation it provokes. Also, its a bloody Friday afternoon.

Rare Breeds Petunias has a straight forward premise and approach: take a random assortment of petunias, and start breeding a colony of them. You can simulate n generations of petunias, and their traits will be passed on based on legit genetic models. Its simpler than breeding for petunia traits in the real world, for sure. Its also a flash game.

So, I've managed to develop RSI, a condition which, when conjoined with the fact that my journal is still absent, makes it extremely challenging for me to be able to recount myriads of hilarious monkey hijinx. However, the journal will be resurfacing very soon (one can't get these things out of order...), and with the aid of the modern science of ergonomics, my hands are doing much better. In the meantime, there's not much at all I can do, which in short, is a real pain... But I think I have one or two plays secreted away for special occasions.

Relevant recent research round-up

Much has been going on in the various realms of mind research, and quite a little backlog of interesting studies have come off the presses. Stories featured in order of appearance. 

Compulsive eating shares addictive biochemical mechanism with cocaine, heroin abuse, study shows

ScienceDaily (2010-03-29) -- In a newly published study, scientists have shown for the first time that the same molecular mechanisms that drive people into drug addiction are behind the compulsion to overeat, pushing people into obesity. ... > read full article

Addiction fascinates me. I, for one, greatly enjoy eating. I appreciate food, but one can enjoy a good meal and eat a whole lot of it. A few years ago, I could get away with eating any quantity of food, and I wouldn't gain any significant quantity of weight. That's changed lately, which bothers me since I appear to be just as ravenous in my desire for food. Am I addicted to eating? If one combines the statistics for obesity, alcoholism, and drug addictions, I get the feeling you'd find yourself confronted with a disturbingly large portion of the population. This problem may be more prevalent in the States, which is apt enough, since NIH funds the research.

Unconscious learning uses old parts of the brain

ScienceDaily (2010-04-07) -- A new study provides evidence that basic human learning systems use areas of the brain that also exist in the most primitive vertebrates, such as certain fish, reptiles and amphibians. The study involved an investigation into the limbic striatum, one of the evolutionarily oldest parts of the brain, and the ability to learn movements, consciously and unconsciously, through repetition. ... > read full article

I am a big "fan" of studying the unconscious parts of the brain. The older it gets, the more important it is for our functionality. Of course, if you look at stuff that is too old, then you wind up dealing with medulla structures which regulate the contractions of your digestive track. Since consciousness is probably a very recent development, it makes perfect sense that unconscious (implicit) learning and memory is tied to older brain structures. Its good that someone confirmed this.

Brain shuts off in response to healer's prayer - life - 27 April 2010 - New Scientist

WHEN we fall under the spell of a charismatic figure, areas of the brain responsible for scepticism and vigilance become less active. That's the finding of a study which looked at people's response to prayers spoken by someone purportedly possessing divine healing powers...

I'd like to begin by stating that I heartily dislike The New Scientist. I was going to say that I "abhor" the publication, but that isn't quite accurate. I would be okay if TNS accepted its role as a popular, light science publication, but they continually attempt to make themselves out to be a serious journal, which the quality of their reports prohibits.

Anyway, this research is still pretty interesting. I'd definitely wager that this commanding effect of charismatic leaders can be seen outside of religious domains.

Social networking helps hermit crabs find homes

ScienceDaily (2010-04-28) -- Biologists have discovered that, contrary to their name, hermit crabs may locate new and improved housing using previously unknown social networking skills. These behaviors may shed light on any animal that relies on discrete and reusable resources, from hole-nesting woodpeckers to urban apartment dwellers. ... > read full article

Despite the buzz-wordiness of the title, this is exceptionally interesting stuff - they've discovered new behaviors among hermit crabs! If a crab in need of a home finds an empty shell that is too large, it will wait around for another crab to come by and take the shell in hopes of picking up the larger crab's old shell. I won't argue that there are massive impacts on our understanding of human social behavior, but still, that's pretty neat.

Researcher explores role of human behavior in infectious disease emergence

ScienceDaily (2010-04-30) -- A wildlife scientist has examined how different human behaviors influence disease transmission between domestic dogs and the African wild dog, an endangered species. ... > read full article

On that last note, here's a study which definitely does have a lot to say about the betterment of the human condition via understanding social behavior. On reading this story, my first musing concerned how far back these human-dog social behaviors related to disease go back. Dog domestication could easily predate the agricultural revolution, and possibly even the formation of complex hunter-gatherers. Thus, the origin of these behaviors might be evolutionary and not environmental, which ought to alter our approach to handling these issues.

How nerve cells distinguish odors

ScienceDaily (2010-05-03) -- Whether different odors can be quickly distinguished depends on certain synapses in the brain that inhibit nerve stimulation. Researchers have shown that mice in which a certain receptor in the olfactory center is missing can distinguish similar smells more quickly than mice without genetic manipulation. ... > read full article

 Once, I did a bit of work in the neuroscience of taste and smell perception (in rats and mice). I worked at the systems/behavioral level, but there's a great deal more research occurring one step down, at the cellular level. This stuff is some pretty heavy neurochemistry, but if you are up to date on that knowledge, this is intriguing research.

Cavemen among us: Some humans are 4 percent Neanderthal - CSMonitor.com

We have met Neanderthals, and they are us – or about 1 to 4 percent of each of us.

That is one implication of a four-year effort to sequence the Neanderthal genome – essentially setting out in order some 3 billion combinations of four key molecules that together represent the Neanderthals' genetic blueprint...

Yet another result of the data being churned out of Svante Pääbo's legendary Neanderthal genomics project. As they mention in the article, "the results and their further refinement are expected to yield a treasure-trove of information on what makes modern humans distinct from Neanderthals, humans' closest extinct relative." Considering the prior lack of evidence in favor of any of the conflicting theories of what became of the Neanderthals, this is a fine change of pace. Plus, I'm at a lucky stage in life where I'm not in favor of any of the particular theories, so these findings do not offend my sensibilities.

Blinking neurons give thoughts away

ScienceDaily (2010-05-10) -- Scientists have used a genetic light source to measure brain signals. Electrical currents are invisible to the naked eye -- at least they are when they flow through metal cables. In nerve cells, however, scientists are able to make electrical signals visible. Scientists have now successfully used a specialized fluorescent protein to visualize electrical activity in neurons of living mice. In a milestone study, scientists are able to apply the method to watch activity in nerve cells during animal behavior. ... > read full article

I swear, I had this same idea a couple of years ago, but I didn't   Plus, I honestly didn't see how it would be a more useful technique than modern two-photon imaging techniques. The advantage I did not for see was that if one can ditch the cumbersome microscope equipment needed for two-photon excitation imaging, you could attach a fibre-optic connection which would allow you to visualize brain activity while the animal was behaving. I confess that I have a soft spot for calcium imaging, so I'm quite pleased by this, but there are still some big issues, like the fact that you can't do this in humans, and its hard to visualize the neurons below the top layers of the cortex.

Alrighty then. Until... next month?

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.

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.

The True Meaning of Multi-Ethnic

When the results of a collaborative project between MIT and Stellenbosch studying the population genetics of a unique South African racial group shows up on PubMed, I really have no choice but to give it some attention.

First set of background info: in South Africa, there is a group of people known as "Coloreds" who make up about 9% of the total population, but in Cape Town, Coloreds make up a whopping 48% of the population. They are by far the largest demographic group here - second place goes to Blacks with 31%, and third is won by Whites, with 19%. The Coloreds are the result of hundreds of years of interbreeding between the whites who lived here (mostly Afrikaners), their slaves, and other random Africans who just happened to be hanging around. During Apartheid, the Coloreds were given more rights than the Blacks, but their lives were still made to suck.

So you've got this odd ethnic group which has developed over the past half millennium. I already described which groups historians think contributed to the Colored ethnicity, but it isn't a very satisfactory explanation when one wishes to ask such question as to just how much each progenitor race contributed to the formation of the Colored ethnicity.

Since creating a new race is not a particularly common phenomenon, it is an interesting thing to study. Understanding the genetic breakdown of colored South African DNA would arguably be helpful for understanding their medical conditions. Also, I think its a great case study which will become more and more relevant as mixed race breeding grows.

This was a descriptive study, and I like those because unless they're just flat out wrong (unlikely) they're just observations about how things are that we didn't know yet. All around useful stuff. Now that we know that the main contributors to the Colored race are (very very likely) Europeans, South Asians, Indonesians, and IsiXhosa relatives, one can make use of this information for medical purposes, cultural investigations, further racial foundation analyzes; all kinds of stuff.

Unless the methodology is severely flawed, and I haven't taken the time or obtained the expertise to check, then this is a solid paper.

Thanks to Dienekes over at his own genetics and anthropology blog for the link on this one.

Infanticide

Friday's in the field always suck. Lately they've been these epically long days. I could endure such an inconvenience on virtually any other day - I would just go back to HQ and do some fun and maybe even productive stuff. On Fridays its the end of the week and its all been building upon you, and the weekend is so close.

Friday turned out to be a long and somber day. We found the baboons in a usual sleeping spot. As soon as we arrived we became confused, since we kept hearing the "wahoo" call... from a female. A wahoo call is a very specialized male call that only the mature male contenders are known to use. Why was this female seeming to wahoo? She was Alia, mother of the youngest baby baboon in the troop. Or, at least she had been. The baby was nowhere to be seen.

The infant was dead. We knew this because Alia's breasts were full, real full of milk which wasn't getting consumed and didn't have anywhere to go.

The whole tribe seemed to be awkwardly avoiding the subject. After about half an hour with them, I could no longer shake the feeling that this was going to be a very quiet day. Here was this female in mental and physical anguish, screaming out at her fellows. Everyone just kept silent and didn't do anything about it. But what could they do?

... and I just called the troop a tribe. One of those little things that transcends the editing process.

Baboon grieving can be a disturbing reflection of human behavior. Some of the animals appeared to offer comfort by grooming Alia and letting her groom them. Alia was definitely not a high ranking female, but it appeared the rest of the troop was being lenient with her at this time.

Alia spent the whole day barking randomly. This behavior seemed like it a was a nervous tick, not a choice. She would be grooming a juvenile and out of nowhere she'd let loose that bark, often right in the face of the juvenile. She didn't interrupt her grooming for it. Was it a high level decision based behavior? Was it some built in fixed action pattern elicited by this event? Was it a scream of pain just because her chest hurt from being bloated with milk? (Me: I've heard that hurts when they're overly full; Karen: Oh you better believe it.)

Infanticide is never a surprise among baboons. Infant baboons are extremely vulnerable to disease, predators, and their own kind. This case was even less of a shock to us. The previous Friday, when last we saw the troop, Alia and her child had been on the receiving end of a lot of abuse from females and sub-adults. Alia sought protection from an adult male, a common practice among mothers. Aaron is the alpha, but she did not seek him out, so the child was probably not his. No one in the troop would mess with one of his offspring. Alia went to Bertrand,  another adult male, an older gentleman, huge, but missing his canines and past his prime. He would accept her offers of grooming, but did not seem especially interested in her child. Despite still peckering an isolated female every now and then, Bertrand mostly sticks to the grandfathering role. He is often accompanied by a gaggle of small baboon children who are probably his progeny. Alia wanted her child to be one of them. If Bertrand did offer some protection, it clearly was not enough to make the difference.

Aaron is young, and likely only recently took up the mantle of alpha male. The troop used to have many more males in the troops other than Aaron, Bertrand, and Chester. We do not know where the other males went, but their departure was very recent. I have been considering the possibility that Alia's child was the progeny of none of these males, but belonged to one of those absent, perhaps the previous alpha. With the ascendancy of Aaron and the disappearance of the other males, it is in the best interest of the remaining males to kill her child so that she will begin cycling as soon as possible so that she can produce a new offspring who will carry their genetic material.

The male behavior was clear. But why did Alia seem so distraught? Its very far from obvious. All of the complex cognitive states I "witnessed" in the baboons could have been artifacts of my human perception. To say that the experts disagree on the extent of baboon cognition is an understatement. Some behaviors are clearer than others - the baboons certainly did not feel remorse for killing an infant. The mother's own troubles may not have only been the result of swollen breasts and lingering hormonal desires to suckle and hold an infant.

Alone, the feeling of grief or remorse is not an advantageous behavior. Remorse ought only to exist so as to make sure an animal learns from its mistakes and does not repeat them. Grief might come about as a result of slowly changing hormonal levels which cannot adapt so quickly as the brain can. Grief could also serve a  purpose similar to remorse, to make sure the female does not make the same mistake as she did with the child which died. She won't want to go though these pains again, so she'll change and adapt her behavior to avoid these situations. Next time, she'll know what not to do, and it could save her next child's life. She lost fitness by losing her child, but her ability to care for a child is strengthened, thus increasing the survivability of future offspring and hence, her fitness.

Thus it all works out in the end and every one is... happy?