THE LAWS OP ORIENTATION AMONG ANIMALS. 483 



double, but springs before the dogs and is off immediately. The chase 

 presents none of the evolutions which we described above; it is nothing 

 but a race between the herbivorous animal, who has on his side speed, 

 and the carnivorous animal, who has endurance. From the condition of 

 the animal and the speed of the hunting party one can determine before- 

 hand the duration of the chase. We will not dwell longer on these 

 facts so well known to hunters. It is, in fact, sufficient to go through 

 a wood in Sologne, or in any other country abounding in game, to be 

 convinced that the ground is traversed in every direction by trails 

 which do not escape the experienced eyes of the poacher. 



Birds also follow through the air roads invisible to our eyes, but 

 which can be revealed by observation. The bird, like the quadruped, 

 contracts the habit of always returniug to the same point by the same 

 route. We have watched for some time a group of pigeons that returned 

 every day to the fields at the same time. In going, as in coming, they 

 undeviatingly followed a line which we had marked out on the neigh- 

 boring ground. We have observed the same regularity of route in the 

 coming and going of two birds of prey. 



The peasants know very exactly the points which mark the course of 

 the migrations of birds, and turn this knowledge to account by hunt- 

 ing during certain seasons. 



Similar observations have been made on fishes in the sea as well as 

 in rivers, aud the very exact information obtained is put to a daily use 

 by fishermen. 



We will not put further stress on an array of facts long since observed 

 and known. We will limit ourselves to deducing from them a primary 

 conclusion. In the air, on land, or in the water all animals follow routes 

 definitely determined ; their movements seem, therefore, to be subject to 

 other laws than those of caprice or chance. 



II. 



The actions of animals are all dictated by a single law, which each 

 one of them obeys in a different way. The animal is controlled by his 

 environment. If he finds around his home an abundauce of the neces- 

 sities of life, he moves about but little and his existence is passed in a 

 very restricted domain. In the opposite case he lives a very active 

 life, traversing his domain unceasingly, extending its limits as far as 

 possible and sometimes going beyond them. Each animal is thus led 

 to contract habits Avhich become peculiar to him and which constitute 

 his individuality. He obeys the call of instinct, but he seems to have 

 the choice of the means of execution, a certain liberty, while he is sim- 

 ply under the influence of his surroundings. It is necessary to bear 

 this in mind before fixing those general laws to which the movements 

 of the individuals of each species are subject. 



It is a fact known by experiment for some time that an animal mov- 

 ing about in a territory familiar to him is guided in finding his way back 



