110 HUMAN HISTOKY 



Apart from the question as to how the distinctively human 

 stock is related to the rest of the primate stock, there is much to 

 be said for the view that the pre-human ancestor of Miocene 

 times was a small arboreal primate which probably lived in 

 a restricted area. But of the mode of life we have of course no 

 direct knowledge. It is possible, however, that the mode of life 

 of the anthropoid apes may give some indication of the con 

 ditions under which the pre-human ancestor lived. That they 

 are all confined to warm climates in the Old World is suggestive 

 when it is remembered that Pithecanthropus was found in Java. 

 They are all more or less arboreal. The orang seldom comes to 

 the ground ; the chimpanzee, though more arboreal than the 

 gorilla, is less so than the orang, while the gorilla is the least 

 arboreal of all. The first two species construct nests in the trees, 

 and the same is asserted of the gorilla, though this appears to be 

 doubtful. They all adopt in varying degrees a semi-erect attitude 

 from time to time. They exhibit a certain development of the 

 social instinct ; the gorilla is seen in bands, the gibbons con- 

 gregate in the evening in groups. It seems certain that marriage 

 in the sense in which Westermarek employs the term exists 

 among them ; it is asserted that they are all polygamous, though 

 the chimpanzee may be monogamous. In any case they are not 

 promiscuous in their sexual relations. 



If a guess is to be made at all as to the mode of life of the 

 pre-human ancestor, it is most reasonable to assume that it was 

 something after the same kind. But whereas the apes are 

 powerful specialized animals, the pre-human ancestor must have 

 been a weaker and more generalized primate, having specialized 

 only in the increase of the brain. It was this character which 

 undoubtedly enabled him to maintain himself, and which com- 

 pensated for the relative absence of other means of defence. 

 The apes, on the other hand, are well able to look after them- 

 selves. * The orang, as Selenka informs us, is more than a 

 match for the dangerous carnivora with which he has to contend, 

 and the gorilla is monarch of the woods.' 1 



When we survey the Tertiary period as a whole we see that 

 there was a rapid and varied evolution of the mammalian stock 

 in Eocene and Oligocene times which culminated in the Miocene. 



1 Sollas, 'Presidential Address to the Geological Society', 1910, p. 48 (Quart 

 Journ. Geol. Soc., vol. bcvi). 



