250 TYPES OF ANIMAL LIFE 



any one who only observes its motions on the surface of 

 the soil, a position in which it naturally hardly if ever 

 finds itself. Hence arises the apparent disproportionate 

 leng-th of its arms compared with that of its legs, and also 

 the seemingly most defective conformation of its hands and 

 feet. Sloths pass their lives hanging under the branches 

 of trees, back downwards and so they can sleep securely. 

 There they continue to hang even after death, till 

 decomposition has far advanced, as any collecting natu- 

 ralist may chance to find to his great disappointment. 

 Sloths are difficult of detection, partly on account of the 

 slowness of their movements, but more on account of their 

 external appearance ; for they are clothed with dry shaggy 

 hair, often of a greenish tint, so that they are by no means 

 unlike the masse i of moss and lichen with which the 

 forest trees abound. This green tint is not due to the 

 colour of the hair itself, but to a minute algoid plant 

 which lives upon the hair of the animal, the surface of 

 each hair being peculiarly grooved. The growth of this 

 small plant is also further favoured by the excessive 

 dampness of the gloomy tropical forests, ond it soon 

 disappears from the hair of animals kept in captivity in 

 England. 



There are certain small points of structure wherein 

 the sloth more resembles a reptile than a beast, and it is 

 also reptilian in its great tenacity of life and the per- 

 sistence with which muscular movement can be induced 

 in the body after death. It will survive the most 

 severe injuries, and can be given large doses of poison 

 with impunity. Thus the sluggishness of its nature 

 seems to extend into the very substance of its body. 

 Therewith it is naturally a most inoffensive animal, 

 nocturnal in its habits, solitary and almost always silent. 

 The female has usually but a single young one at a time. 



