Footage shows hippos opening wide - stretching their jaws so visitors can drop snacks into their mouths.

The massive animals float through a pool at the Khao Kheow Open Zoo in Chonburi province, eastern Thailand.

Visitors can then drop bananas and other healthy fruit and vegetable treats into their powerful jaws. The hippos crush the food with the massive teeth then swallow it.

The hippopotamus is native to sub-Saharan Africa. They are classed as a vulnerable species by the International Union for Conservation of Nature (IUCN) on its Red List of Threatened Species.

One of their biggest threats comes from poachers, who sell hippo meat and their ivory tusks and teeth. Much of the smuggled hippo ivory finds its way to mainland China, according to the African Wildlife Foundation.