Acacia Goes off Birth Control

Acacia the gorilla might get pregnant this year.

Acacia is the eldest of the three female gorillas living at the North Carolina Zoo.   In the past, she has not been designated for breeding because she has a very well-connected family tree.  She is one of many children of the very prolific Tatu, who himself has more than a few siblings sired by Jambo. Acacia is therefore related in one way or another, to quite a few gorillas in captivity.

Who decides when a captive gorilla will breed? 

The transer and the breeding of captive gorillas are strictly overseen by  the gorilla Species Survival Plan program under the AZA.  The goal of any SSP is to maintain a genetically diverse,  healthy and self-sustaining population of the various species.  All these years, the gorilla SSP has decided not to try to breed Acadia because of the fear of inbreeding. The problem would not effect her children so much,  but it would become an issue for their mating. It would be quite difficult to try and find unrelated gorillas to serve as mates for any of Acacia's babies  But now, suddenly, at age seventeen, Acacia has been taken off of birth control. Why?

The breeding season of 2011-2012 has had a very low yield, with only Bomassa and Apollo and two other gorilla babies born in all of the AZA zoos by midyear 2012. It is unusual to have only four successful gorilla births in a year. More gorillas are needed, so the SSP decided to go ahead and give Acacia a chance. She's not related to Nkosi, the silverback she lives with, and further, she's got an excellent opportunity this year to observe how mother gorillas behave with their babies, which is crucial to the successful raising of those young ones.  So the medicine (which incidentally is the exact same kind of birth control used for women) was stopped and now we are waiting to see what happens. Zoo volunteers told me they have seen Nkosi make a few attempts. While I was standing there, Acacia refused an opportunity, but other times she was willing. So you never know. We could learn any day now that Acacia is pregnant. How will they know for sure? The zookeeper will administer an EPT pregancy test.