One of the largest aquatic frogs in the world, the endangered species goes by a unique nickname. It has "amazingly baggy skin, which gives it the common name scrotum frog," says National Geographic explorer Jonathan Kolby, a PhD student who studies frogs in Latin America.

The deaths occurred along a 30-mile stretch of the Coata River, according to members of the Committee Against the Pollution of the Coata River. The river is a tributary of Lake Titicaca, the highest navigable lake in the world. The lake straddles the border between Peru and Bolivia in the Andes Mountains.