The Lake Titicaca frog is the top endemic predator of Lake Titicaca, the largest entirely aquatic frog on Earth, and the main ingredient of Jugo de Rana (frog juice), a popular aphrodisiac that does not actually gain anything from the addition of frogs. High demand, in addition to lake water extraction, pollution, and introduced trout, has pushed the species to become critically endangered in recent decades. Denver Zoo maintains a population descended from frogs rescued from the Peruvian market and is working with the Heredia University in Lima, Peru, to protect and save these strange-looking frogs.
Fun fact: their ultra-baggy skin has earned them the nickname “scrotum frog” and the position of runner-up in 2013’s “world’s ugliest animal” contest run by the United Kingdom’s Ugly Animal Preservation Society. Also, they can grow to the size of a dinner plate.