112 THE ODYSSEY OF AN ANIMAL COLLECTOR 
toed species the neck vertebrae number nine instead of seven as 
in nearly all other mammals. 
To fit in with his topsy-turvy condition, his hair hangs the 
opposite way to that of other mammals, thus allowing the rain 
to run off. Sloths have no incisor teeth and their molars are 
blackish in color and are lacking in enamel. This subjects the 
teeth to constant wear but to counteract this they continue to grow 
throughout life. 
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‘Two-ToED SLOTH 
These animals seldom drink but do so occasionally with diff- 
culty by climbing along a branch which hangs into the water. In 
the heat of the tropics I have several times seen captive sloths 
drinking and this was always a slow laborious business—one suck- 
ing away for fully half an hour before quenching its thirst. 
All sloths have three toes on the hind feet, thus the names 
Three-toed and Two-toed are in reference to the front feet. The 
Three-toed Sloth is perfectly harmless but the larger Two-toed 
species is usually very aggressive until tamed and can give a nasty 
bite. The young, like those of most arboreal mammals that are 
