Many mothers eat their offspring within the first moments of giving birth: arachnids, rodents and insects. This is part of nature's plan to stem population.

It is rumored that the mother of someone I knew personally was unable to stand the constant wailing of her baby, the howling, blubbering, drooling, shitting, snot ridden screaming bag of vomit for another moment! So she tore it's head off ... and ended her obligation.