Our keepers are very good at their job and they regularly check over each animal to assess them for health issues. Last week one of our keepers discovered that Bolungwa is already changing her teeth. This means that she is around 5 years old. We are all very surprised as she is very small. Just as we were surprised 6 months ago when Yonguesa changed her teeth, however, we were surprised for the opposite reason. Yonguesa is huge-and you would assume she is older than 5 years by her size and her dominance over the other chimpanzees! Of course, like with people the teeth rule is not absolute, but it is a good guide for us as we have to try to estimate the age of the individuals. Also, chimpanzees from different areas can differ greatly in size. Bolungwa is a very sweet little chimpanzee and although she is quiet within the group she has a very big personality.