How does a hippo keep its teeth clean? With a giant toothbrush of course!
This zoo-keeper at the Tennoji Zoo, in Japan, has been tasked with brushing 'Tetsuo' the hippopotamus's giant choppers.
Hippos have up to 40 teeth, some of which can grow up to half a metre in length.
They usually let fish and birds clean their teeth for them, so it was a bit of a change to have a human help them to clean their teeth.
Hippos usually use their teeth for fighting and eating tough plants, so it's better to leave the cleaning to the professionals.