Figure 1. Female Leah Using a Walking Stick while Crossing Bipedally through an Elephant Pool at Mbeli Bai

Female Leah first looked at the new elephant pool and the branch she later used as the walking stick, and entered the water without the tool (not shown). After re-entering the pool and taking the branch with her right hand, she walked bipedally 8–10 m into the water, frequently testing water deepness.