POPULAR SCIENCE 9S 



that Darwin remarks upon the advantages of man beginning 

 as a weak animal, because it would compel him to remain social. 

 Schoetensack claims that the necessary conditions of safety- 

 point to Australia as being the place of man's evolution ; and 

 Klaatsch goes so far as to hold that the apes are degenerate 

 branches of the pre-human stock, the way upward being cut 

 off in particular by the reduction of the thumb. We have 

 remarked that the gibbons have become best adapted for their 

 new life because they left the sands while they were still small 

 animals in the Oligocene. The other species have a precarious 

 hold on continued survival because they faced the new con- 

 ditions after their feet were too specialised to turn into first-class 

 tree-climbing organs, and their teeth were too large to acquire 

 the sharp posterior edge of the canines of the baboon. 



Man Evolved in Safety 



The evidence that man was evolved in conditions of com- 

 parative safety, so that the struggle was less severe than in 

 the case of other animals, may be deduced from many points 

 of structure and function. First of all, the removal of the 

 need for continuous watchfulness may have set free the growing 

 brain, allowing of the development of intelligence instead of 

 instinct. The more rigorous the conditions of life the more 

 rigid the instincts. Amongst vertebrates we may instance the 

 penguin and the beaver. The wariness of birds is well known. 

 Thus in Australia the white cockatoo lives in large flocks and 

 always stations a picquet in the trees while the flock is feeding 

 on the ground. Similar care is taken in selecting a tree upon 

 which to roost at night. This instinct is carried a stage farther 

 by the antarctic penguins, which are safe on the ice, but are 

 eaten by a large " shark " in the water. The flock marches 

 down from the rookery to the ice edge, where they line up 

 and try to push one another into the water. The photographs 

 of the birds watching over the edge to see the fate of the 

 unwilling scout are well known. If he begins fishing, they 

 know that all is safe, and drop into the water also. If he 

 disappears, they go back to the rookery and wait for a more 

 auspicious omen. Their absence of fear on the ice is seen in 

 the nesting instincts. The male " proposes " to the female 

 by placing a stone in front of her as the first step towards 

 building a nest. If she accepts it, they regard each other as 

 man and wife. But a bachelor bird will propose in the same 

 way to a sailor if he stand quiet for a few minutes. The dam 

 of the beaver, the modification of the tail wherewith to smooth 

 the outside of the mud house before it is frozen, and the canals 

 which are made to keep the pond full, are some of the instincts 



