The Houston Zoo is wishing chimpanzee Willie a very Happy Birthday! Over the past five years, since the opening of the chimpanzee exhibit in 2010, we have watched as Willie has grown from a playful juvenile chimpanzee to a mature adult chimpanzee. During this past year, he has risen in rank to become the dominant male in the group.
When Willie first came to the Houston Zoo, he was the smallest member of the group and at six years old still spent the majority of his time with Lulu and Lucy, the mothers of the group. He continued to rely on them for protection during group conflicts and his primary goal in life and in interactions with the group was to just have fun and play. He played an important part in getting the original chimpanzee group comfortable living together in their new home as his solution to any tension or nervousness was to encourage everyone to play!
In the wild, chimpanzees spend the first seven years of their lives with their mothers. These juvenile chimpanzees are characterized by tan faces and a white tuft of hair above their rear ends. Between the ages of 6-9, adolescent chimpanzees will start interacting more socially with other members of the group. They lose their white tuft of hair and their faces start to change from a light tan color to black. During this time, males will spend less and less time with their family and more time interacting with adult males in the group. It is during this time that young males start participating in boundary patrols and begin to try to figure out their place in the male hierarchy. These young ‘teenage’ chimpanzees often find themselves involved more in conflicts as they try pushing boundaries and establishing themselves in the hierarchy.
At eight years old, Willie started spending less time with Lucy and Lulu and more time with Mac, the dominant male at the time. Keepers called him “Mac’s Shadow” as he would never be very far from Mac’s side. He always seemed to be looking to Mac for guidance on how to behave. During this time, Willie also started challenging the females and lower ranking males. Anytime a conflict occurred, you could find Willie right in the middle of it. His favorite tactic was to throw dirt and then run away before anyone could catch him. The only chimpanzee that could discipline ‘teenage’ Willie successfully was Mac. Willie gained rank quickly.
Over the last two years, the original chimpanzee group has been integrated with a new chimpanzee group of six chimpanzees. Willie initially was very friendly but shy about meeting his new friends. His initial interactions with the new chimpanzees were submissive and friendly. Due to his friendly initial interactions and his playful nature, Willie quickly made friends with the new chimpanzees. As the groups were combined and Willie became more confident in the new group, keepers started noticing him intervening in conflicts instead of causing them. Keepers also noticed that many of the chimpanzees started to look to Willie for reassurance and support during conflicts. One of a dominant male chimpanzee’s main roles is to manage conflict within the group. Willie seemed to be fulfilling this role in the new group.
Willie can often be found at the center of grooming and play sessions within the newly combined chimpanzee group. Besides being strong enough to maintain order, another important trait for a high ranking chimpanzee is the ability to gain and maintain allies. Bullies usually don’t last long as dominant males as the other chimpanzees in a group often band together and overthrow them. Willie’s friendly nature has gained him lots of allies. Even though he is now in charge, his favorite strategy to maintaining order is to encourage everyone to play. The one thing that has not changed about Willie in the past five years is that his primary goal in life is to just have fun and play!
Chimpanzees in zoos can live into their sixties. We look forward to celebrating many more birthdays with Willie and watching him as he continues to learn and grow into an impressive adult male chimpanzee!