Darwin thought that some were "rhinos" (Old World mammals), yet Owen showed that they were indigenous giant armadillos, sloths and anteaters.

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They afford a unique opportunity to go on several jungle tours each day, with guides pointing out monkeys, birds, caimans, and sloths.

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Sloths lumber in the branches high above.

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The next day in the five-million acre Pacaya-Samiria National Reserve, the sun burned bright, giving an electric glow to the throbbing canopy where parakeets swooped, sloths napped and tamarind and red howler monkeys played.

BBC: Taming the heart of the Peruvian Amazon

At Corcovado you can find tapirs, jaguars, pumas, anteaters, two-toed and three-toed sloths, golden orb spiders, moon crabs, a diversification of monkeys (including all four types of Costa Rican monkeys, found only in Corcovado), crocodiles, poison dart frogs, pelicans, 220 species of butterflies, scarlet macaws and even the rare and venomous fer-de-lance snake.

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