Filial cannibalism occurs when an adult individual of a species consumes all or part of the young of its own species or immediate offspring. Filial cannibalism occurs in many animal species ranging from mammals to insects, and is especially prevalent in various species of fish. Exact evolutionary purpose of the practice in those species is unclear and there is no verifiable consensus among zoologists; it is agreed upon though that it may have, or may have had at some point in species' evolutionary history, certain evolutionary and ecological implications. Types Total Total or whole clutch cannibalism occurs when a parent consumes its entire brood. This usually occurs when a brood is smaller or of lesser quality. The most obvious purpose of total or whole clutch cannibalism is the termination of care for the parents. The main benefit of this action can only be an investment in the future reproduction of potentially larger or healthier broods. Partial Partial clutch cannibalism occurs when a parent consumes a part of its offspring. "Parental manipulation of brood size may allow the parent the maximize lifetime reproductive output by adjusting current reproductive costs in favour of future survival and subsequent opportunities for reproduction." Unlike total or whole clutch cannibalism, partial clutch cannibalism invests in both current and future reproduction. Male parents, particularly male fish, may eat some of their offspring "complete his current parental cycle, and remain in sufficiently good condition to engage in further breeding cycles." Benefits Satisfies current energy or nutrition requirements In a non-reproductive environment, is a way to recoup reproductive investment Puts evolutionary pressure on offspring to make the offspring develop quicker May increase the reproductive rate of a parent by making that parent more attractive to potential mates Gets rid of offspring that take too long to mature, allowing the parent to halt parental and resume reproductive behavior quickly Removes weaker offspring in an overproduced brood, which makes the other offspring more likely to succeed Reduction of sick, parasitized, or non-viable offspring. Costs Loss of immediate fitness Transmission of diseases and parasites Social factors Competition among a species for resources, mating opportunities, and reproductive dominance are all promoters for filial cannibalism. To compete well in a certain species' social structure, a parent may be compelled to practice filial cannibalism to limit the amount of energy and time they spend raising their young. Males may compete for mating opportunities by eating