Not Living up to their Name - - Max Planck scientists find evidence that sloths in the wild sleep a lot less than previously thought. [PDF.
Pale-throated Three-toed Sloth: Bradypus tridactylus - - Research project by Joe Thomas on this tree-living mammal including its classification, habitat, reproduction, adaptations, nutrition and interactions with other species.
Three-toed Sloth - - Information from Wikipedia on the four sloths included in the Bradypodidae family.
Two-toed Sloth - - Information from Wikipedia on the classification of the family Megalonychidae which contains just two species, Choloepus didactylus and Choloepus hoffmanni.