Confined entirely to Isla Escudo de Veraguas, a small island off the coast of Panama, the world´s rarest species of sloth is the pygmy three-toed sloth (Bradypus pygmaeus), scientifically described as a new species as recently as 2001. Critically endangered according to the IUCN, only approximately 300 specimens are thought to exist. They live exclusively in red mangrove trees.