350 



THE RISE OF ANIMAL LIFE 



Fig. 13-68. Lemurs are primitive primates that are found 

 only in isolated parts of the world. They are stupid, 

 sluggish animals. This is the ring-tailed lemur, lemur 

 cafta. 



The mother primate gives birth to single 

 offspring as a rule, and multiple births are 

 rare. This is to be expected in an arboreal 

 animal, since a single young one is about all 

 she could manage in the tree tops. She 



lavishes meticulous care and protection on 

 her offspring, keeping it close to her chest 

 at all times during the first few months of 

 its life, close to the food supply. Primates 

 possess only two mammae or breasts al- 

 though occasionally even in humans several 

 pairs may appear, located in the same posi- 

 tion as on the lower mammals which pro- 

 duce multiple offspring (Fig. 25-16). The 

 ungulates, such as horses and cattle, for ex- 

 ample, also produce a single offspring at 

 a time but in this case the mammae are 

 in the pelvic region. Dogs, on the other 

 hand, produce numerous young at one time 

 and consequently multiple mammary 

 glands are necessary for all to get their 

 share of the milk. The development and 

 location of the mammae seem to be cor- 

 related with the number of offspring and 

 the method of caring for them. 



The various primates 



The lemurs. The lethargic lemurs are not 

 i^reatly removed from the insectivores ( Fig. 

 13-67). They are slow moving, sluggish, 

 stupid animals quite unlike the other pri- 

 mates. Their primitive nature is indicated 

 by the fact that their eyes still lie in such 

 a lateral position that their images do not 

 overlap (Fig. 13-68). They live in the tree 

 tops where they move about so conserva- 

 tively and cautiously that they are rarely 

 seen by enemies and consequently have 

 been able to survive in Madagascar up to 

 the present time. They would not have 

 lasted long if they had been forced to com- 

 pete with their aggressive cousins. 



Tarsier. The East Indies are the home of 

 the only hopping primate, which is not 

 much bigger than a rat (Fig. 13-69). Its 

 mark of distinction lies in the fact that 

 zoologists consider it intermediate between 

 the lemurs and the monkeys. Its rat-like tail 

 and long legs are well adapted for leaping, 

 which it performs with great agility. The 

 swollen tips of its digits are useful in catch- 

 ing limbs of trees as it forages for insects 

 during its nocturnal sorties. The extremely 



