Existence of over 500 ‘lost’ animal species remains uncertain, study says

Researchers hope findings will help make the lost species a focus in future searches

The Miles’ robber frog is endemic to Honduras and thought to be extinct but was rediscovered in 2008 (Tom Brown)

There are over 500 “lost” animal species that haven’t been seen by anyone in more than 50 years but are not yet considered extinct, according to a new study.

The research, published in the journal Animal Conservation, provides the first global evaluation of all terrestrial vertebrate species that are missing but not extinct, identifying 562 such species.

In the study, an international team of scientists reviewed information on 32,802 species from the International Union for Conservation of Nature Red List of Threatened Species (IUCN Red List).