Animal Tales

World-Traveling Bonobo


Hannah, a 10-year-old bonobo, was transferred to Frankfurt Zoo in Germany earlier this year.

International travel is often complicated, but it’s even more complicated when you have a great ape with you. Stacy Whitaker, a keeper at the Milwaukee County Zoo, knows that better than anyone after spending 36 hours transporting Hannah, a 10-year-old bonobo, to her new home at the Frankfurt Zoo in Germany in April. But even with the hassle of travel and the sadness of saying good-bye to Hannah, she’s excited about what the transfer means for the bonobo population.

A transfer like this takes years of planning, and with good reason. The breeding of endangered animals like bonobos is carefully tracked at accredited zoos through Species Survival Plans® in North America and the European Endangered Species Programme. The Zoological Society of Milwaukee has hosted the Bonobo Species Survival Plan (SSP) since it was created in 1988 under the direction of the Society’s conservation coordinator, Dr. Gay Reinartz. “The goal is to maintain a healthy captive population and genetic diversity over the generations,” says Auriana Gilliland-Lloyd, Zoological Society conservation assistant. “In order to do that, we have to work with all the institutions holding bonobos.”

Bonobos are only represented at 17 accredited zoos in North America, Europe and Japan, so maintaining genetic diversity is especially tricky. The Milwaukee County Zoo acquired its first bonobos in 1986 and now has the largest population in North America with 19. Every two years, Reinartz and her team lead the effort to create a breeding and transfer plan for the Bonobo SSP, while at the same time working closely with their European counterparts to manage the global captive population. The most recent plan recommended sending Hannah to Germany.

Bonobo Hannah

Hannah waits out her time in quarantine with another new bonobo before joining the rest of the bonobos at the Frankfurt Zoo.

Hannah is descended from several “founders” of the captive bonobo population, or wild-born bonobos from which the current zoo population descended. Zoos no longer take animals from the wild except for rehabilitation purposes, so it’s important to make sure the founders’ genes are spread across the population to prevent inbreeding. Hannah’s father and maternal grandparents were founders in the SSP who were not represented in European zoos. In the wild, females leave the bonobo group upon maturity to find mates, says Whitaker, the Milwaukee County Zoo’s lead bonobo keeper. For that reason, the SSP tries to transfer female bonobos instead of males. Hannah was the right age to leave, Whitaker says. “She was ready to be a mom.”

It took a year and a half to get the international endangered species permits to send Hannah overseas. She had to pass vigorous health checks before she left Milwaukee and was inspected at her departure and arrival airports. Hannah traveled in the cargo hold, but Whitaker went along as a passenger to be a familiar face when Hannah arrived in Frankfurt. Even though she passed all her health checks, Hannah was required by law to stay in quarantine in Frankfurt for a couple of months before joining the other bonobos.

After all that, Hannah was introduced to the Frankfurt group in July, and everything went smoothly, Whitaker says. “Bonobos are pretty resilient and accepting of new individuals,” she says. The Milwaukee bonobos quickly adjusted to Hannah’s absence, since it would have been natural for her to leave the group at this age. Whitaker gets regular updates from the Frankfurt Zoo, and she will see Hannah again next year when she travels there for a conference. “I hope she has a baby by then,” Whitaker says.

By Stacy Vogel Davis

This article appeared in the fall 2018 issue of Alive magazine.