Although the hippo looks intimidating and can be aggressive during the dry seasons, one at Osaka's Tennoji zoo has been showing its docile side, while enjoying a teeth cleaning service from a vigilant zoo keeper. Adults can have as many as 40 teeth.

Hippo in Osaka's zoo enjoys teeth-cleaning service?

This hippo is fed fruit and vegetables daily, which tends to get wedged between them. After the examination and cleaning, he gets fresh fruit as a reward.