The Outline of Science 



their own lambs. If we are to form a sound judgment or 

 the intelligence of mammals we must not attend too much to 

 those that have profited by man's training, nor to those whose 

 mental life has been dulled by domestication. 



Instinctive Aptitudes 



What is to be said of the behaviour of beavers who gnaw the 

 base of a tree with their chisel-edged teeth till only a narrow core 

 i s i e ft to snap in the first gale, bringing the useful branches 

 down to the ground? What is to be said of the harvest-mouse 

 constructing its nest, or of the squirrel making cache after cache 

 of nuts? These and many similar pieces of behaviour are funda- 

 mentally instinctive, due to inborn predispositions of nerve-cells 

 and muscle-cells. But in mammals they seem to be often attended 

 by a certain amount of intelligent attention, saving the creature 

 from the tyranny of routine so marked in the ways of ants and 

 bees. 



Sheer Dexterity 



Besides instinctive aptitudes, which are exhibited in almost 

 equal perfection by all the members of the same species, there are 

 acquired dexterities which depend on individual opportunities. 

 They are also marked by being outside and beyond ordinary rou- 

 tine not that any rigorous boundary line can be drawn. We read 

 that at Mathura on the Jumna doles of food are provided by the 

 piety of pilgrims for the sacred river-tortoises, which are so 

 crowded when there is food going that their smooth carapaces 

 form a more or less continuous raft across the river. On that 

 unsteady slippery bridge the Langur monkeys (Semnopithecus 

 entellus) venture out and in spite of vicious snaps secure a share 

 of the booty. This picture of the monkeys securing a footing on 

 the moving mass of turtle-backs is almost a diagram of sheer 

 dexterity. It illustrates the spirit of adventure, the will to ex- 

 periment, which is, we believe, the main motive-force in 

 departures in behaviour. 



