THE LIFE OF MAMMALS 
-posedly to intimidate their enemies, such as wild-cats, tree 
serpents, and such birds of prey as the harpy eagle, but there 
is no evidence that any one of these is at all frightened by the 
noise. Humboldt and other early writers believed that big 
bands must assemble and howl in chorus; but Wallace showed 
by his own studies, and by the unanimous testimony of the 
Indians, that one individual alone makes the roar, which he 
describes as of remarkable depth and volume. Waterton 
vividly portrays the effect on the traveler’s mind as he lies in 
his hammock in the forest and listens to these unearthly cries. 
The Indians hate the howlers, finding them too dull and sullen 
to tame, and so kill them for food, to sell their hides to white 
traders, or for the sake of the long hair, which is twisted into 
cordage and otherwise utilized. 
Coming to the sakis and ooakaris (or “yarkees’”’), we find 
a group with non-prehensile tails and the incisor teeth inclined 
forward. The sakis (Pithecia) have long, bushy tails, 
the hair on the head long and parted in the middle, 
and a thick beard; the body is not large. They are very delicate, 
so that it is rarely one can be kept long alive, nor is it often 
attempted, for they 
are uninteresting 
and likely to be 
cross as captives. 
Of the five species 
none are very well 
known ; the largest 
is the black cuxio, 
and the most strik- 
‘ 
Sakis. 
BLACK SAKI, CUXIO, OR SATAN MONKEY. ing is the rare 
white - nosed saki, 
whose face is scarlet except the white end of its nose. 
The three species of ooakaris are quaint little monkeys with 
very short tails, and their light-colored silky coats set off by a 
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