GIANT SLOTHS AND ARMADILLOS. 187 
numbers, for successful races multiply while unsuccessful ones 
diminish. Victory is not always to the great and the strong, for 
cunning and quickness are often of more service than mere brute 
strength ; and perhaps the sloths, as we now see them in the 
Brazilian forests, have hit upon “a new and original plan 2, Dy 
means of which the old colossal forms described above have been 
driven out of the field, and so exterminated by a process of com- 
petition. Such an explanation would be in thorough harmony 
with modern teaching, and, as the other suggestion about long- 
continued droughts, given on p. 184, may not appear satisfactory to 
some of our readers, we offer this theory for what it may be worth. 
A few words about these modern sloths may not be out of 
place; for we shall better understand how they have succeeded 
in the struggle for existence when we know something of their 
manner of life; and in some ways they still resemble their great 
ancestors. 
There are few animals which exhibit in a greater degree what 
appears to the careless observer to be deformity than the sloth, 
and none that have, on this account, been more maligned by » 
naturalists. Buffon, and many of the older zoologists, were 
eloquent upon the supposed defects of the unfortunate sloth. 
These writers gravely asserted that when the sloth ascends a tree, 
for the purpose of feeding upon its leaves, it is so lazy that it will 
not quit its station until every trace of verdure is devoured. Some 
of them even went so far as to assert that when the sloth was 
compelled, after thus stripping a tree, to look out for a fresh 
supply of food, it would not take the trouble to descend the tree, 
but just allowed itself to drop from a branch to the ground. 
Even Cuvier, who ought to have known better, echoes this tale, and 
insinuates that Nature, becoming weary of perfection, ‘‘ wished 
to amuse herself by producing something imperfect and grotesque,” 
when the sloths were formed; and he proceeds, with great gravity, 
to show the “inconvenience of organisation,’ which, in his 
opinion, rendered the sloths unfit for the enjoyment of life. 
