The less terrible Carnivora give Buffaloes no trouble. Wolves do not dare to attack them when they are united; they await in ambush the passage of some strayed calf, and rapidly gain possession of it before the rest of the flock are aware, or they would dearly pay for their attack. The Bisons of North America, near relatives of the Buffaloes, also repulse Wolves in common; and if Man succeeds better against them it is owing to the skill which he shows in hiding himself and not attracting their attention. Every one knows how Indians hunt the Bison with arrows, and his pursuit is very risky to the hunter, for he must not be discovered by the game, as he would then be trodden underfoot or disembowelled. In the immense prairies where these ruminants feed, a few Indians covered by bisons' skins advance on all fours, so that nothing betrays their presence. The victims fall one by one beneath silent blows, and their companions, who can see nothing suspicious in the neighbourhood, are not disturbed, supposing them, no doubt, to be peacefully resting. It is not only against other animals that these great mammals have to defend themselves; they are much afraid of heat, and they are accustomed, especially in the south of Persia, to ruminate while lying in the water during the hot hours of the day. They only allow the end of the snout, or at most the head, to appear. It is a curious spectacle when fording a river to see emerge from the reeds the great heads and calm eyes of the Buffaloes, who follow with astonishment all the movements of the horsemen, although nothing will disturb their sweet and fresh siesta. But let us return to defences arranged in common. Horses are extremely sociable, and in the immense pampas of South America those who become wild again live in large troops. In difficult circumstances they help one another. If a great danger threatens them all the colts and mares assemble together, and the stallions form a circle round the group, ready to drive back the assailant. But they do not accomplish this manoeuvre in the presence of an enemy of small importance. When a wolf appears on the plain all the males run after him, seeking to strike him with their feet and kill him, unless prompt flight delivers him from their blows.