Photo of the Day 350

Hippo, Zambezi River, Africa, 1997

Photograph by Chris Johns

The gape-mouthed territorial display of a dominant male hippopotamus, such as this one on the Zambezi River, looks more like a colossal yawn. During mating season, males will claim a length of shoreline and fiercely defend it, occasionally even killing a bachelor rival.

(Photo shot on assignment for, but not published in, "Down the Zambezi," October 1997, National Geographic magazine)