There's major flawed logic there, and anyone who has raised animals knows it. There are individual animals, including humans, who bear offspring but reject them for reasons unrelated to offspring themselves. They're simply bad mothers. Should the offspring die because something is wrong with the mother? I can't speak for polar bears, but other animals will occasionally "adopt" rejected offspring; I've seen cats do this before. One cat bears kittens, leaves them, and another mother cat with kittens takes on the new litter. This guy seems to think that the mother sensed something wrong with the offspring and that was the reason for rejection; it's just as possible that she simply isn't a good mother.