In the case of the little kapok bird of the Cape, a beautiful, white, fluffy round nest is made by both out of the white down of a certain plant, and immediately below the entrance to the cavity in which the little female sits on the eggs is a small shelf or basket, in which the tiny male sits to watch over and guard them.

It is among certain orders of birds that sex manifestations appear to assume their most harmonious and poetical forms on earth.

Among gallinaceous birds, on the other hand, where the cock is much larger and more pugnacious than the female, and which are polygamous, the cock does not court the female by song, but seizes her by force, and shows little or no interest in his offspring, neither sharing in the brooding nor feeding the young; and even at times seizing any tempting morsel which the young or the hen may have discovered.
Among mammals the male form tends to be slightly larger than the female, though not always (the female whale, for instance, being larger than the male); the male also tends to be more pugnacious and less careful of the young; though to this rule also there are exceptions.

In the case of the South African mierkat, for instance, the female is generally more combative and more difficult to tame than the male; and it is the males who from the moment of birth watch over the young with the most passionate and tender solicitude, keeping them warm under their persons, carrying them to places of safety in their mouths, and feeding them till full grown; and this they do not only for their own young, but to any young who may be brought in contact with them.

We have known a male mierkat so assiduous in feeding young that were quite unrelated to himself, taking to them every morsel of food given him, that we have been compelled to shut him up in a room alone when feeding him, to prevent his starving himself to death: the male mierkat thus exhibiting exactly those psychic qualities which are generally regarded as peculiarly feminine; the females, on the other hand, being far more pugnacious towards each other than are the males.
Among mammals generally, except the tendency to greater pugnacity shown by the male towards other males, and the greater solicitude for the young shown generally by the female form, but not always; the psychic differences between the two sex forms are not great.