Troop Dreams

How Denver Zoo’s Efforts to Forge a New Mandrill Family Unit Resulted in the Ultimate Success

By Tenley Davis, Primate Care Specialist

In 2002 and 2003, Denver Zoo welcomed two baby mandrills, Tuki and Saba, which was both exciting and exhausting for our primate care team. Mandrills are the largest species of monkey and considered vulnerable in their native range of Western-Central Africa. Their bright blue faces make them a must-see in the Congo Basin area of Primate Panorama. Since our success with Tuki and Saba, we’ve tried and tried again to bring a new mandrill baby into the world without success. That all changed earlier this year with the birth of Kesi, who is the first mandrill born at the Zoo in 16 years. But would you believe it took two years of planning and preparation—and a bit of luck—to make it happen? 

First Things First

In 2017, the primate team decided we wanted to have a family troop again. We already had a 12-year-old male named Jelani, who came to Denver Zoo in 2013, so we needed to find females that could be his potential mate. Our first step was to work with the Association of Zoos and Aquariums Mandrill Species Survival Plan (SSP). The SSP located two females to send to Denver and pair with Jelani. Both girls would be coming from Florida—Ruby from Disney's Animal Kingdom and Kumani from Jacksonville Zoo and Gardens.  

While we prepared for the girls’ arrivals, the primate team had many meetings and conference calls with mandrill experts. It took numerous discussions to ensure we were doing the best for these animals, as well as going over all the options on how to introduce them to the animals already at the Zoo. Like most primates, males are the dominant animal in the troop, but there’s also a hierarchy among the females in a troop. That’s why it’s extremely important to review everyone's history. We look at what other mandrills they’ve lived with, how they behaved in those groupings and how each mandrill interacts with animal care staff.  

After months of preparation, Ruby arrived in February of 2018 with Kumani joining her a few weeks later. 

Nice to Meet You

Even with all our planning and research, we can never predict how an animal is going to get along with another. It’s is why we have detailed introduction plans that cover a range of outcomes. You can never be too prepared! 

In April 2018, we had our first introduction between Ruby and Jelani. The two didn't exactly hit it off, but were able to get them to cohabitate for the next couple weeks. Soon after, Kumani and Tuki joined the group. This arrangement worked well at first, but after some conflict, Jelani had to be pulled out. Over the summer the girls were given a chance to bond, sort out their dominance and settle into their new home. In the fall, Jelani was re-introduced back to Ruby and Kumani. This time was an instant success and the group settled in to their new dynamic.  

Baby on Board

Toward the end of 2018, animal care staff noticed some changes in Kumani and suspected she was pregnant. To confirm our hunch, we trained Kumani for voluntary ultrasounds. After a few practice sessions with the ultrasound gel and mock probe, we brought in our reproductive specialist, Dr. Anneke Moresco, to help us with the real thing. It took a few tries, but we got our ultrasound images and found that Kumani was expecting! From then on, ultrasounds were acquired weekly as long as Kumani was comfortable and participated. This allowed us to follow her pregnancy, making sure baby and mom remained healthy.   

Mandrills have a 175-day gestation period. We estimated a due date of May 2 based on tracking Kumani’s cycle. That means we had less than four months to get ready! During this time, Kumani was trained for several maternal behaviors so we would be able to assist her if motherhood proved difficult. Behaviors included a ‘pick up baby’ and raising it to her chest. All this extra training may not be necessary if Kumani is a great mom, but it helps us prepare for all scenarios. We also developed a 14-page birth plan outlining everyone’s role in the birth and, you guessed it, backup plans!   

Final Countdown

After months of preparation, Kumani’s birth window started on April 17. During this time, overnight care staff would check cameras and Kumani’s team would check in on her more frequently while monitoring physical and behavioral changes. May 2 came and went as we anxiously awaited the new arrival. At 10:39 p.m. on May 10, we finally got the text we’ve been waiting for—Kumani gave birth! During an overnight check, our overnight animal care staff member noticed Kumani was holding a new little baby. To ensure Kumani and baby were healthy, primate staff immediately came to the Zoo to check in. Things looked good, so we let the new family rest for the evening. Much to our relief, Kumani proved to be a great mom from the start. She held baby correctly, groomed her, and allowed her to nurse all the time. The only thing for us to do was give the new baby a name. As a team, we decided Kesi was the perfect name for this new addition. 

A New Normal

Jelani, Kumani and Ruby were a fairly new troop, so we wanted to take our time introducing Kesi to everyone. We made decisions based on each mandrill’s behavior and if they were comfortable moving forward. We started with Ruby, who kept her distance from mom and baby, which shows a level of respect for Kesi. After several days of rest for Kumani and bonding time with Ruby, it was time for Jelani to meet Kesi. Though he wasn’t physically with the troop after Kesi’s birth, Jelani could see the baby and was aware of the new arrival. When the group was put together, everybody did their own thing as if nothing had changed. Jelani would walk by Kumani and Kesi, and respect their space. Ruby spent a lot of time grooming the new father (he must look good for the baby!). This dynamic is exactly what the primate team had been planning and hoping for.  

Come Meet Kesi!

At six weeks old, Kesi’s growing fast and is already showing signs of a big personality. Kumani does what she can to keep Kesi close, but we can tell this girl is itching to explore the mandrill habitat on her own! Seeing her thrive and knowing what it took to get here makes those little milestones even more significant. Make sure you come see Kesi and the whole troop in the Congo Basin area in Primate Panorama on your next visit. The best times to see our mandrills are first thing in the morning and lunchtime, when they’re foraging for food we’ve left around their habitat. Be sure to follow us on Facebook, Twitter and Instagram for regular updates on Kesi!