Sloths More Vulnerable to Predators Than Previously Thought

Sloth hanging in a tree

Henry Alien / Flickr / CC BY-NC 2.0

Researchers monitoring three-toed sloths in the jungles of Panama came upon a shocking discovery after one of their radio-collared animals stopped moving. The sloth had been killed, its organs eaten, and left on the forest floor. Upon closer inspection, researchers determined the sloth to be a victim of a surprising killer: The tiny spectacled owl.

The owl, which typically measures less than 20 inches tall and weighs less than three pounds, is a small bird of prey. It looks especially diminutive when compared to the sloth, which is typically twice as long and as much as four times as heavy. But, as this recent kill demonstrates, the sloths unique adaptations make it vulnerable—even more so than previously thought—to predators big and small.

The sloth is one of the world's slowest animals and it's thought that this slowness, combined with a system of camouflage that uses algae-laden fur, is actually a defense mechanism. Three-toed sloths blend in seamlessly with their home in the canopy of the forest.

Once every eight days, however, sloths travel out of their leafy homes and descend to the forest floor. They do so to defecate and it is thought that this mysterious behavior places them in danger of predation. Bryson Voirin, a researcher with the Max Planck Institute of Ornithology, explained that:

We think the evolutionary strategy of this cryptic lifestyle has opened them up to a wider range of predators.

He went on to say that sloths "are relatively large, so one would expect their predators to be limited to harpy eagles and ocelots." The fact that such a comparatively small bird of prey was able to kill a sloth, researchers believe, is further evidence that the animals are almost completely defenseless on the ground.