The zoo’s two new infant gorillas aren’t just a milestone for the new gorilla moms and their social group at Regenstein Center for African Apes. They’re also the culmination of years of planning and cooperation by more than 50 zoos and hundreds of zoo professionals—keepers, curators, directors, vets, institutional representatives, advisors and more—around the country.

New mom Rollie cuddles with her baby, born November 16.

You see, moms Bana and Rollie and dad Kwan are part of a larger community, a population comprised of 342 gorillas residing at Association of Zoos and Aquariums (AZA)–accredited zoos around the country, all managed under the AZA Gorilla Species Survival Plan®. Just as the health and welfare of individual gorillas (and their newborns) is the focus of keepers and curators, the health and welfare of full zoo populations is the focus of the AZA Population Management Center (PMC), which is based at Lincoln Park Zoo.

The PMC advises hundreds of AZA animal populations to help keep them stable, genetically diverse and sustainable long into the future. PMC biologists monitor populations like gorillas with the help of studbook keepers, who record the parentage and life events of every single animal, and species coordinators, who gather requests and input from every AZA zoo that holds the species.

To develop plans to meet the needs of the zoos, individual animals and the population as a whole, the PMC regularly hosts Gorilla SSP meetings (in person or virtually) with the species coordinator, studbook keeper and institutional representatives from the more than 50 participating zoos that hold gorillas. Once together, everyone examines the results of demographic and genetic analyses to find the best possible matches for breeding. Such a meeting took place at Oklahoma City in 2009 and led to the decision to move Bana from Brookfield Zoo to breed with Kwan.

Bana holds her baby, Patty, who was born October 11.

The decision to move a large social animal like a gorilla is not taken lightly, but Bana and Kwan were both genetically valuable, not related to each other (no inbreeding!) and lived in close proximity, so the match was very appealing.
The PMC analyses also revealed another good breeding opportunity—one already at Lincoln Park Zoo! Young female Rollie was a good match for Kwan and only needed to move across the building, from silverback JoJo’s group.

Dad Kwan watches over the group--and the two new babies.

A total of 30 other gorillas were recommended to breed based on similar factors, the goal being to help produce the right number of births to keep the gorilla population at the desired size while maintaining genetic diversity by breeding gorillas from under-represented family lines.

Since gorillas don’t typically live in pairs but in social groups with multiple animals of different sexes and ages, the SSP also considered the genetic and behavioral compatibility of all the gorillas that would live together after the moves occurred. After careful consideration of age, personality and genetic background, the SSP recommendations resulted in two females moving out of Kwan’s group to join social groups at other zoos. Rollie moved over from JoJo’s group, and Bana moved in from Brookfield.

Soon after their first meeting, Kwan and his new female companions showed signs that the matches selected by humans were also approved by the gorillas themselves. And two newborn babies provide the ultimate evidence of successful matchmaking!

Sarah Long

Sarah Long, M.S., is director of the AZA Population Management Center, based at Lincoln Park Zoo.