August 26: Utamu's Expecting

 We are excited to announce that Utamu, an 18-year-old chimpanzee at the Saint Louis Zoo, is pregnant and due to give birth this fall at Jungle of the Apes. The pregnancy is based on a breeding recommendation by the Association of Zoos and Aquariums Chimpanzee Species Survival Plan. 

“The primate team working with our chimpanzee troop is very experienced and highly skilled. The strong, trusting relationships they have built with the chimps is integral in providing the high level of care and training to prepare for this important pending birth,” said Heidi Hellmuth, Curator of Primates, Saint Louis Zoo.
Click here for more info. 
Check back for updates as we follow Utamu's Path to Motherhood. 

Photos: Ethan Riepl 

September 2: Getting to know Utamu

Utamu was born on December 20, 2001, in Florida at the Miami Metrozoo (now called Zoo Miami). She first arrived at the Saint Louis Zoo as a juvenile chimpanzee in early 2007 along with her mother Rosebud. She has benefited greatly from Rosebud’s social personality and popularity with the other chimpanzees, as they both easily integrated in the group. Rosebud and Utamu are often found in the middle of any social interaction such as playing or grooming. Even though Utamu is older now, she continues to share a strong bond with her mother Rosebud and they support each other within the group. Growing up with her mother always watching out for her and often being the center of social interactions, she is a very confident, social and respected chimpanzee within the group.
Utamu has a very distinctive ‘voice’. Her laugh and food vocalizations can easily be picked out by keepers from the rest of the chimpanzees. Since she is so well liked, she is good at getting what she wants, especially food. Even when she was little, she could usually get someone such as Beauty, a female in her late 40s, and Jimiyu , a 28-year-old male, to share food by food peering, which is when a chimpanzee gets really close (within inches) of another chimp who is eating something delicious and just stares. This probably wouldn’t work as well for us humans as it does for Utamu, though!
When not relaxing or eating, Utamu is often seen playing with her two close pals, 18-year-old Tammy and 22-year-old Bakhari, two female chimpanzees. These three are close in age and all enjoy a good play-chase or wrestling session complete with tickling. As she has progressed in her pregnancy, Utamu is usually more inclined to relax with her mother and Beauty than engage in rambunctious play, but her friends can often still get her to engage in more laid-back tickle sessions.
Utamu’s favorite locations are hanging out high on the habitat hammocks or relaxing in the viewing shelter windows under the air vents with the other female chimps. First thing in the morning, you can usually spot her grooming and foraging with the rest of the chimpanzee group on the large rock overhang in the center of their habitat.

September 9: Discovering a pregnancy

So just how did the primate care team find out that Utamu was pregnant you might wonder?

It might be helpful to begin with a little background information on chimpanzee female reproductive cycles.

Chimpanzees have about a 36-day reproductive cycle. The primate care team is able to track this cycle for all the female chimpanzees as part of our daily husbandry monitoring. When a female is ovulating or “can become pregnant,” she develops what is called an estrus swelling. Her behind swells up looking a little like a small inflated pink balloon. For the rest of her cycle, this area is deflated and has loose pink skin. Female chimpanzees also menstruate during their cycle. So if one of these events is missing or late, it can often be the first indication of a potential pregnancy to the primate care team.

Utamu with full estrus swelling.

Rosebud with no estrus swelling.

How do we confirm a chimpanzee pregnancy?

We use an at home pregnancy test, the exact same type that you would use to confirm a pregnancy for a human! Utamu is trained to urinate when asked and this can then be collected and applied to a home pregnancy test.

We also have a secondary method to confirm pregnancy:

You might not know this but the Saint Louis Zoo has its own endocrinologist, Corinne Kozlowski, Ph.D., and an endocrinology laboratory. One way to have a secondary verification of a chimpanzee pregnancy is to compare progesterone levels of a suspected pregnant chimpanzee to progesterone levels of a non-pregnant female chimpanzee. Progesterone levels rise during pregnancy. The care team is able to submit fecal samples from the chimpanzees collected during daily cleaning to the lab where Dr. Kozlowski can evaluate them.

Continue to follow Utamu: Path to Motherhood to learn more about Utamu’s pregnancy and the work being done by Saint Louis Zoo staff in preparation for the upcoming birth.

September 16:  Being a Chimpanzee Mom

The length of a chimpanzee pregnancy is just slightly shorter than that of a human pregnancy at 8 months. Chimpanzee moms are very hands-on for the first several years of the infant’s life and typically have intervals of 4 to 6 years between births because of this. Even when a chimpanzee mother has another baby, the older siblings will typically still stay close to mom, giving the juvenile female offspring the opportunity to learn important skills about caring for infants that will aid them with their own offspring in the future. 

Chimpanzee babies will typically nurse from their mother for up to 5 years, even after regularly eating solid foods. Chimpanzees are born with very strong grasping abilities, as they need to cling to their mother’s belly as she climbs and moves around. As they get older they will transition to riding on their mom’s back. Eventually they will start to venture off of mom to explore and play, but always staying in close range and still climbing on her back for a ride when moving from place to place.

Being a chimpanzee mom is a very important and difficult job. They may have help from other members of the troop but they are the main caretaker and are responsible for keeping their offspring safe. Mother chimpanzees are also responsible for teaching their offspring what food to eat, how to act in the social hierarchy, how to use tools, how to build nests, and a lot of other vital information that will help the young chimpanzee survive and thrive. We are looking forward to seeing what an amazing mom Utamu will be!


Utamu and Rosebud

Utamu and Rosebud

Beauty and Utamu