The five: back-from-the-brink species once thought extinct

From wild dogs to horned frogs, all manner of animals are still capable of keeping out of our sight, some for over 100 years

This week, scientists in South America spotted a rare frog previously thought to be extinct. The Tropical Herving research group found a colony of horned marsupial frogs in a recent expedition into the Choco rainforest. The species had last been seen in Ecuador in 2005. The frogs' natural habitat is in the high canopy of the rainforest, threatened by deforestation.