I recently finished off my Primate Conservation course and it really opened my eyes a lot. I’m really, really grateful for having the ability to have taken that class and for the professor for teaching that class. She’s a fantastic primatologist and someone I really admire for all she’s accomplished. As a result, I find it fitting to write about captive breeding today because I think it’s a subject worth considering as a conservation method for population management, at the very least.
It’s not uncommon for a lot of captive breeding programs to fail miserably when it comes to primates; they’re very expensive to maintain (especially as you go towards the greater apes), they’re social animals, and because we can’t understand some of the communication methods primates use, we can’t fully tend to their needs. Moreover, captive breeding programs that exist to eventually release subjects into the wild also have to be careful about domestication, genetic inbreeding, potential disease transmission, and even the politics of the country of habitat they intend to release individuals back into as to avoid possible slaughter for hungry troops if there’s a war going on. And most importantly: captive breeding staff must be careful to not entirely domesticate and desensitize the individuals from not being able to recognize predators (which includes humans).
Another consideration is the captive environment itself and how it contributes to the potential setback of captive breeding programs. In strictly captive settings where the primates are kept in a caged or enclosed environment, the potential for disease transmission increases as there are less places to avoid the ill individual. In a study performed by Willete et al. (2007) in a captive setting, rhesus macaques who were injected with lipopolysaccharides were discovered to have a strong leukocyte response (which isn’t surprising, since they act as endotoxins and call for a strong immune response). Also, in this study (and here’s where it’s pertinent to captive breeding programs), they measured the cortisol levels of the macaques at certain points; the one that raised the highest cortisol was when they used the human-intruder paradigm.
Why is that significant? Because the human-intruder paradigm may mirror zoo-goers in a given day. Particularly when its crowds of people and they all may not be gearing their attention towards the primates in question. So if there’s even more people rather than just the one, maybe it’s possible that the increased cortisol can limit reproductive abilities. But that’s just a postulate and may not be applicable to all primates; some may even like the crowds because it gives them something to look at–I’ve seen this with chimpanzees watching the crowds at the Henry Vilas Zoo here.
So my jury is still out on zoos as an effective captive breeding program (sure, it works with golden lion tamarins, but I’m not sure how well it might work out with those primates with slower life histories who are more specialized; if there are any other success stories, I’d love to hear them though!). But, I do think there’s something with semi-captive breeding programs, specifically when they’re in the country of origin.
Specifically, I am thinking of the Peignot et al. (2008) study on the first successful translocation of mandrills in Gabon. In a released group of 36 captive-bred mandrills who were raised in a semi-captive environment, the mortality rate of the first year was 33% with infants being the most affected individuals. However, in the second year, the number decreased to 4%. From what I understood, Peignot et al. attributes this to the mandrills becoming more acclimated to their new environment and becoming accustomed to food availability during seasonal shifts; additionally, the provisioning was eventually reduced and taken away.
So why the success? I think it a lot of it contributes to the fact that mandrills are extremely plastic: they’re opportunistic omnivores and will generally eat anything. However, I’m willing to bet that the consideration to where and how these individuals were raised also plays a part. For instance, these mandrills were raised in semi-captive conditions as opposed to cages or enclosures which allowed for more foraging, more exploration of the environment, and they were able to acclimate to both the temperature and environment since they were raised in the CIMRF (Centre International de Recherches Médicales de Franceville) in Gabon, where they were translocated as well. And because they didn’t have to go through the stressor of being placed on a plane and being shipped to a different country or anything else that may contribute such as that, the program saved themselves a pretty penny and were able to reroute the funds elsewhere.
So, I’m still not sold on the fact that captive breeding is a waste of time and resources. I think there’s legitimacy to the idea that captive breeding can contribute to enhancing populations; I just think there needs to be more considerations given pre-translocation/release to ensure that the released population can be viable.
Peignot, P., Charpentier, M.J.E., Bout, N., Bourry, O., Massima, U., Dosimont, O., Terramorsi, R., & Wickings, E.J. (2008). Learning from the first release project of captive-bred mandrills (Mandrillus sphinx) in Gabon. Oryx, 42(1), 122-131.
Willete, A.A., Lubach, G.R., & Coe, C.L. (2007). Environmental context differentially affects behavioral, leukocyte, cortisol, and interleukin-6 responses to low doses of endotoxin in the rhesus monkey. Brain, Behavior, and Immunity, 21(6), 807-815.