Zoo Knoxville celebrated two exciting birthdays on Wednesday. Gorillas Obi and Ubuntu turned 4 years old this week.

“They’re really at that stage where they’re starting to explore becoming more independent, away from mom, and getting more curious about being a gorilla. Traveling further away in the yard from their mom. So it’s really fun to watch them explore and grow up and be their own gorilla,” said zookeeper Corie Herbert.

In celebration of their big day, Obi and Ubuntu were given a number of treats. One of their favorites is Jello along with ice treats and popcorn.

Their yard was also filled with streamers, bubble buckets and other so-called “enrichment items” so they have fun things to interact with throughout the day.