The persecution of a sick animal by its companions comes next under consideration.
It will have been remarked, with surprise by some readers, no doubt, that I have set down as two different instincts this persecution of a sick or weakly individual by its fellows, and the sudden deadly rage that sometimes impels the herd to turn upon and destroy a wounded or distressed companion. It is usual for writers on the instincts of animals to speak of them as one: and I presume that they regard this sudden deadly rage of several individuals against a companion as merely an extreme form of the common persecuting instinct or impulse. They are not really one, but are as distinct in origin and character as it is possible for any two instincts to be. The violent and fatal impulse starts simultaneously into life and action, and is contagious, affecting all the members of the herd like a sudden madness. The other is neither violent nor contagious: the persecution is intermittent: it is often confined to one or to a very few members of the herd, and seldom joined in by the chief member, the leader or head to whom all the others give way.
Concerning this head of the herd, or flock, or pack, it is necessary to say something more. Some gregarious animals, particularly birds, live together in the most perfect peace and amity; and here no leader is required, because in their long association together as a species in flocks, they have attained to a oneness of mind, so to speak, which causes them to move or rest, and to act at all times harmoniously together, as if controlled and guided by an extrane-ous force. I may mention that the kindly instinct in animals, which is almost universal between male and female in the vertebrates, is most apparent in these harmoniously acting birds. Thus, in La Plata, I have remarked, in more than one species, that a lame or sick individual, unable to keop pace with the flock and find its food, has not only been waited for, but in some cases some of the flock have constantly attended it, keeping close to it both when flying and on the ground; and, I have no doubt, feeding it just as they would have fed their young.
Naturally among such kinds no one member is of more consideration than another. But among mammals such equality and harmony is rare. The instinct of one and all is to lord it over the others, with the result that one more powerful or domineering gets the mastery, to keep it thereafter as long as he can. The lower animals are, in this respect, very much like us; and in all kinds that are at all fierce-tempered the mastery of one over all, and of a few under him over the others, is most salutary; indeed, it is inconceivable that they should be able to exist together under any other system.