102 THE TRIUMPH OF THE MAMMALS 



The great order of the Ungulates (hoofed animals) 

 spread over the four continents, and generally de- 

 veloped speed. The hippopotamus relied on bulk, 

 and life in the water. The rhinoceros got bulk, a 

 good coat of mail, and a horn. The elephant also 

 had weight, a fair speed in case of need, and a pair 

 of very formidable canine teeth (tusks). But the 

 majority developed high speed and keen scent. 



The ancestors of all these hoofed animals had five 

 toes on each foot. We have numbers of remains of 

 them; and there is a little animal in Africa to-day, 

 the Hyrax, which goes back a long way towards them, 

 as it had four toes on the front feet and three on the 

 hind feet. But you have only to count the toes of 

 your cat, and remember that carnivores and vege- 

 tarians had a common ancestor, to realize this. 

 Running tends to reduce the number of toes. If you 

 watch an athlete waiting for the pistol at the begin- 

 ning of a race, 3^ou see how he stands "on tiptoe." 

 In running the weight of the body is lifted as much 

 as possible off the soles of the feet and thrown on the 

 toes. And if the toes are like the human fingers, 

 longer in the centre and shorter at the sides, the 

 weight is thrown on the central toes, and the side toes 

 disappear. The horse became in time a three-toed 

 animal, as the rhinoceros is. But the ancestors of 

 the rhinoceros stopped there, and developed bulk and 

 armour. The ancestors of the horse continued to 

 rely on flight, two further toes disappeared, and the 



