Cora May Williams, A Review of the Systems of Ethics Founded on the Theory of Evolution
“ One of the forms of such aid most common in the whole range of animal species is the care of the parent animal for its offspring. This care is more usual on the part of the female than on that of the male, and where it is exercised it is not the exception, but rather the rule, that the mother will sacrifice life itself in the defence of her young. Such care and self-sacrifice, especially marked in mammals and birds, are too well known to need illustration here. ”
