Mother Camel and Baby, Sahara, Chad, 1999

A young dromedary camel peeks underneath its mother as she casually drinks in the Guelta Archeï, a steep canyon in the Chadian Sahara. But camels beware. These isolated waters hold a zoological surprise: Algae, fertilized by camel droppings, are eaten by fish that are preyed upon by a group of crocodiles.

(Text adapted from and photo shot on assignment for, but not published in, "Journey to the Heart of the Sahara," March 1999, National Geographic magazine)