In some species of Anglerfish, the male is much smaller than the female and incapable of feeding independently. To survive he must smell out a female as soon as he hatches. He bites into her releasing an enzime which fuses him to her permanently. He lives off her blood for the rest of his life, providing her with sperm whenever she needs it. Females can have multiple males attached. The morale is simple: males are parasites, women are sluts. Ha! Just kidding! The moral is don't treat actual animal behavior like a fable. Generally speaking, animals have no interest in teaching you anything.

Oglaf (Original comic NSFW)