THE EXTINCT GROUND-SLOTHS 1379 



Sloths are mainly nocturnal, and in their usual attitude they hang suspended 

 back downward. When sleeping, they roll themselves into a ball, with the head 

 tucked between the arms; in this position they somewhat resemble the pottos among 

 the lemurs, and it is then that they present the most striking resemblance to a 

 lichen-clad knot. They are found usually either in pairs or in small family parties; 

 and are harmless and inoffensive in disposition. They are most active in the dusk 

 and at night, and will then wander slowly for considerable distances through the 

 forest. Their food consists exclusively of leaves, young shoots, and fruits, the 

 moisture of which renders drinking unnecessary. Their favorite food is afforded by 

 the large-leaved and milky cecropia trees, which are so abundant in the South- 

 American forests, and it is said that they seldom desert a cecropia so long as it af- 

 fords them nutriment. 



The sense of hearing in these animals seems but imperfectly developed, and 

 their small, dull and reddish eyes do not appear capable of very acute vision. In- 

 deed, on first observing a sloth its eyes look so devoid of brightness as to give the 

 impression that the creature must be blind. But a single young is produced at a 

 birth. When it first comes into the world the young sloth is fully developed, hav- 

 ing the body thickly clothed with hair, and the claws on the toes of the same pro- 

 portionate length as in the adult. With these claws it clings fast to the long hair 

 of its mother, clasping its arms around her neck. 



Sloths are capable of enduring deprivation from food for protracted periods, 

 and they are also remarkable for the severe bodily injuries they are capable of sus- 

 taining, while they appear to be unaffected by doses of poison which would immedi- 

 ately prove fatal to other animals of larger size. It is related that on one occasion 

 a three-toed sloth kept in captivity at Turin took no food for upward of a month, 

 and appeared none the worse at the end of its long fast. All these circumstances 

 clearly point to the low organization of these animals; it being a well-known fact 

 that reptiles exhibit a far greater tenacity of life than the higher Mammals. In- 

 deed, as a rule, the lower we descend in the animal kingdom, the greater becomes 

 the power of sustaining injury. 



THE EXTINCT GROUND-SLOTHS 



Family MEGATHERIIDsE 



No account of the Edentates would be complete without some reference to the 

 gigantic ground-sloths which were formerly so abundant in South America, as it is 

 by their aid alone that we are able to comprehend the relationship of the true sloths 

 to the ant-eaters. The best known of these creatures is the megathere, which 

 rivaled the elephant in bulk; while the mylodon and scelidothere were somewhat 

 smaller forms. They may be described as possessing the skulls and teeth of sloths, 

 and the backbones, limbs, and tails of ant-eaters. The megathere differs from most 

 of the others in having the crowns of the teeth square and divided into wedge- 

 shaped transverse ridges, owing to the variation in the hardness of their constitu- 

 ents; but in most cases the teeth were subcylindrical, with depressed centres. They 



