Note AA — Chapter XI · DEVELOPMENT OF THE REPRODUCTIVE IMPULSE

Among animals, says Walker, there are species that never marry and those that do. Those male animals whose young are easily fed, such as the horse, the bull or the dog, never approach the female except when under the influence of rut, never cohabit with one exclusively, rarely, if ever, repeat the reproductive act with the same individual, and commit the care of the offspring entirely to their temporary mates.