LECTURE XXVIII

§ I. Social Instincts ; Temporary Associations and Friendships
OF Animals. § II. Animal Marriage. § III. Animal Societies
AND States.

§  I

NEW and peculiar conditions for the development of in¬
stincts are to be found in the common life of animals.
This is, of course, a product of social instincts; but it
reacts in  the most various ways upon the original impulses
which occasioned it.

At the very lowest stages of animal life we see every crea¬
ture seeking its like. Many of the meduss and molluscs,
many insects and fish, unite temporarily in swarms or schools.
In all such cases it is not the individuals, but the species, which
know one another. At the same time, the origin of the social
impulse can only be looked for in a feeling of inclination, how¬
ever primitive, which attracts animals of the same species
towards each other by the intermediation of certain sense-
impressions,—perhaps of smell or sight. At a higher stage of
development this feeling of inclination shows itself as an indi¬
vidual attraction of animal to animal. But this is not found until
we come to the higher birds and mammals. Dogs, as you of
course know, manifest very pronounced likes and dislikes. If
two poodles, e.g., are kept in the same house, there may spring
up between them a kind of friendship ; the survivor mourns the
loss of his comiade. Horses from the same stable become
similarly attached to one another. Most remarkable are the
friendships which arise between animals of different species as
a result of living together. Even a dog and a cat may become
friends. The inclination in all these cases is purely individuaL
The dog will pick out his comrades from a score of other dogs ;
and however gracious his behaviour to a particular cat, will
chase all her companions with true canine hostility.