662 Marvels of the Universe 
that the rattle is used, not as a danger-signal, but as a means of protection. The Rattlesnake is not 
the most venomous of snakes, and is supplied with only a limited quantity of poison. He therefore 
only uses it under great provocation and upon a persistent enemy. He has discovered that his 
poisoning propensity has made him dangerous and a creature to be feared. | He therefore works on 
that fear by sounding the alarm. The more timid of his foes will immediately retreat and the 
Rattler be left undisturbed, without serious interruption of his sluggish habits and without loss to 
his cherished store of poison. 
GIANT GROUND SLOTHS 
BY R. I. POCOCK, F.R.S. 
SOUTH AMERICA possesses many strange animals, but perhaps none more strange and grotesque 
than the Sloths which spend their lives suspended upside-down to the branches of the forest trees, 
and the Great Ant-eaters, which prowl beneath in search of the colonies of White Ants upon which 
they feed. Nor would it be easy to find amongst related animals a greater contrast than these 
iO present. The Ant-eater has a snout of preposterous length, with a huge bushy tail to match, 
while the Sloth has a short and 
rounded head, and can boast 
at most a mere vestige of a 
caudal appendage. Yet that 
these animals are related, and 
tolerably intimately related too, 
is proved by the former exist- 
ence in South America of 
immense beasts, whose struc- 
ture may be briefly epitomized 
by saying that they had the 
heads of Sloths, the bodies and 
limbs of Ant-eaters, and_ tails 
which were a compromise be- 
tween those of the other two 
in length. These are the Giant 
Ground Sloths, of which the 
best-known forms are the 
Megatherium, as large as a 
rhinoceros, and the Mylodon 
of about half that bulk. 
Judging from the structure 
of the mouth and teeth, and 
comparing them with those of 
the Sloths, which feed entirely 
upon leaves, there is no doubt 
that these animals were vege- 
tarians likewise; but it is 
equally certain that they did 
Tea SF ERTOne not climb trees in search of 
SKELETONS OF THE GIANT SLOTH. their food, for few trees grow 
The largest kind of Sloth was about the size of a Rhinoceros, and they are the branches strong enough to 
skeletons of this species which are shown here. The smaller kind were about half 
the size of their giant kindred. 
Photo by] 
support such a weight. They 
