"This was a female of his kind, and it was a law of his kind that the males must not fight the females. He did not know anything about this law, for it was no generalization of the mind, not a something acquired by experience in the world. He knew it as a secret prompting, as an urge of instinct - of the same instinct that made him howl at the moon and starts of nights and that made him fear death and the unknown."