Friday, June 11

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.

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