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?