The three-toed sloth is not well informed about the outside world. On a scale of 2 to 10, where 2 represents unusual dullness and 10 extreme acuity, Beebe (1926) gave the sloth's senses of taste, touch, sight and hearing a rating of 2, and its sense of smell a rating of 3. If you come upon a sleeping three-toed sloth in the wild, two or three nudges should suffice to awaken it; it will then look sleepily in every direction but yours. Why it should look about is uncertain since the sloth sees everything in a Magoo-like blur. As for hearing, the sloth is not so much deaf as uninterested in sound. Beebe reported that firing guns next to sleeping or feeding sloths elicited little reaction. And the sloth's slightly better sense of smell should not be overestimated. They are said to be able to sniff and avoid decayed branches, but Bullock (1968) reported that sloths fall to the ground clinging to decayed branches "often".
How does it survive, you might ask.
Precisely by being so slow. Sleepiness and slothfulness keep it out of harm's way, away from the notice of jaguars, ocelots, harpy eagles and anacondas. A sloth's hairs shelter an algae that is brown during the dry season and green during the wet season, so the animal blends in with the surrounding moss and foliage and looks like a nest of white ants or of squirrels, or like nothing at all but part of a tree.
The three-toed sloth lives a peaceful, vegetarian life in perfect harmony with its environment. "A good-natured smile is forever on its lips," reported Tirler (1966). I have seen that smile with my own eyes. I am not one given to projecting human traits and emotions onto animals, but many a time during that month in Brazil, looking up at sloths in repose, I felt I was in the presence of upside-down yogis deep in meditation or hermits deep in prayer, wise beings whose intense imaginative lives were beyond the reach of my scientific probing.
Sometimes I got my majors mixed up. A number of my fellow religious-studies students--muddled agnostics who didn't know which way was up, who were in the thrall of reason, that fool's gold for the bright--reminded me of the three-toed sloth; and the three-toed sloth, such a beautiful example of the miracle of life, reminded me of God