DANTAisms

Why are owl monkeys good fathers?

Owl Monkey Family

In the (non-human) primate world there are many different social organizations with many different degrees of paternal care. A male can contribute a range of minimal to almost all of the effort. Usually for primates the degree to which the male will help is determined by paternal certainty. This is when a male is certain that he is the father of the infant. In monogamous species paternal certainty should be 100%. There are cases of extra-pair copulations (when a mating happens with an individual outside of the pair), but I won’t get into that in this post.

Owl monkeys are considered serial monogamists because when a mate leaves or dies the individual will find a new mate to pair with. The male or female will disperse and find a new mate after a few years. In most cases they will enter an already defined group and replace the current same-sex mate. In other primate species, such as Hanuman langurs, the new male will commit infanticide. Infanticide is a strategy for the male because it causes the female to re-enter estrous, allowing this new male to reproduce with her sooner (than waiting until the infant is weaned). Since the new male knows any existing infants are not his, he is willing to partake in this strategy.

Here is where I tell you this is not always the case. When owl monkey males replace a resident male, if there are infants present, they care for them as if they were their own. WHAT? That’s crazy..why would he do that? Well, it is has been theorized that they do it for a mating strategy. Here is his opportunity to show this female that he is a good father and “worthwhile” to mate with.

Owl monkey fathers begin caring for the infants within two weeks of their birth doing the majority of the carrying, food sharing, and play behaviors.

(source)

That’s a lot of work for an infant that isn’t yours! Well, it turns out that the infanticide strategy will not work on female owl monkeys. Unlike other female primates, even if a female loses an infant she does not immediately resume cycling. She will not be able to reproduce again until the next breeding season, which occurs annually. If the infant survives, even if they are not weaned, she is still able to reproduce during the breeding season. It appears that the males are taking care of these “foreign” infants because (1) there is no gain from committing infanticide, and (2) it’s a mating, or courtship, strategy. Another potential reason is that helping care for the infants reduces stress for the females and therefore ensures she is healthy the next breeding season. This could also be considered a mating strategy.

Dr. Fernandez-Duque and colleagues are working hard to uncover these answers about owl monkey reproduction. While more studies are always needed to further define and support these findings, it appears that they have an understanding of why owl monkeys are good fathers.