Cannibalism

Cannibalism is the process in which an organism eats another individual of its own species for food. While scientists previously thought that this behavior only occurred during stressful periods when other food sources are in short supply, research has shown that it is actually quite common in nature, even under normal environmental conditions. Various forms of cannibalism have been observed in many different species, with different motivations behind the act.

The most persuasive reason why cannibalism takes place within a species is the need to survive. Paramount to survival is the necessity to have a diet sufficient to support development and continued existence. Competition for survival begins at birth and continues throughout the life cycle of the animal. Since most animals produce more young than can survive, it sometimes occurs that the strongest of the young feeds on the weakest. Young mantids (praying mantises), black widow spiderlings, cane toads, and varieties of young salamanders, for example, often feast on their brothers and sisters as soon as they are born. In some varieties of sharks, only one or two shark pups are born from the large number of eggs that the mother shark carried during gestation; the surviving shark pups consume their brothers and sisters before birth.

Another reason for cannibalism, also related to the need to survive, is eliminating competitors within an ecosystem. Some young tiger salamanders, when living in extremely crowded conditions, develop special structures in their mouths that enable them to eat other salamanders that are their competitors. Adult male Kodiak bears often kill and eat young cubs, especially male cubs, as a means of both supplementing their diet and eliminating future competitors. Male lions and male feral cats are also known to kill and eat the cubs of another male, thus enabling them to mate with the mother of those cubs and ensure that their own offspring will survive. Male chimpanzees are also known to engage in the practice of killing and eating infants of females that they have not impregnated. Sometimes, in a process known as matriphagy, the young eat their mothers. Crab spiders and caecilians are two such species.

Sometimes cannibalism is related either to the lack of enough food or to a diet deficiency. Two popular household pets, guppies and gerbils, eat their young if there is not enough food available. Female gerbils also cannibalize their own or another female’s litter as a means of gaining more protein in their diet. Furthermore, livestock may be forced into cannibalism by the practice of feeding them by-products of slaughtered animals to increase their protein intake; this practice is believed to have spread bovine spongiform encephalopathy, or "mad cow disease," among cattle.

Some animals appear especially capable of consuming members of their species if there nothing else is readily available. Tyrannosaurus rex, the famous prehistoric predator, was apparently in that category. Scientists have discovered that the North American T. rex may have devoured members of its own group to gain a fast and easy meal. South American horned frogs apparently feed on anything, including fellow horned frogs, that moves near them.

One form of cannibalism still perplexes scientists. During the mating and reproduction process, some female members of the animal kingdom kill and later consume their suitors, an act known as sexual cannibalism. It is mostly seen in insects, particularly arachnids, and often in species displaying prominent sexual dimorphism. Praying mantises and black widow spiders are perhaps best known for this practice, but not all black widows eat their mates after killing them. Scientists have discovered that if the female black widow spider is not hungry, she will not consume her dead mate. The female praying mantis, however, will always devour her mate after she has killed him. In very few species, reverse sexual cannibalism—in which males eat females—has been observed, though rarely. Several theories have been postulated to explain sexual cannibalism, and research into the phenomenon continues.

Human Cannibalism

While factors that explain cannibalism among animals can also be applied to humans, there are several other possibilities to examine in the case of humans. Prehistoric humans are thought to have, at times, engaged in cannibalism as a means of survival, and modern human cannibalism because of a natural disaster or an accident has also been recorded. There are stories of shipwrecked sailors resorting to cannibalism of their dead and even murder and cannibalism to survive. Perhaps two of the most famous instances of modern cannibalism forced by starvation were the 1846-1847 experience of the Donner Party in the Sierra Nevada Mountains in California, and the 1972 incident involving the Andes mountain crash of a plane carrying a Uruguayan soccer team. In both instances, the survivors resorted to cannibalism (but not murder) to withstand the peril they faced.

However, the human animal is unique in that cannibalism is also practiced as a social and religious custom not involving subsistence and survival in the normal sense. In fact, some research has suggested that the nutritional value of the human body is relatively low, providing far fewer calories than other animals. This has led many scientists to believe that hominins, including early humans, mostly practiced cannibalism for ritual rather than dietary purposes. Such ritual practice continued among some cultures well into the twentieth century.

One type of human cannibalism involves a genuine reverence by relatives for their dead. Called endocannibalism, this practice is based upon the belief that eating the flesh of departed relatives shows great respect and veneration of the dead. This type was practiced among the natives of islands of the southern Pacific Ocean until it was declared illegal following World War II.

Exocannibalism, or the eating of unrelated individuals, has ritualistic and religious overtones as well. Indigenous warriors of the South Pacific, popularly referred to as headhunters, ate parts of their vanquished opponents as a means of controlling them and gaining their strength. Sixteenth-century Indigenous South Americans mixed the eating of captured enslaved peoples with religion, making the cannibalistic ritual into a festival. Indeed, it was actions similar to these, observed by the Spanish, that gave us the word "cannibal"— Columbus incorrectly transcribed the name of the human-eating Caribs of Cuba as Canibalis. Though their numbers are few, there are still small, isolated societies in the world still believed to practice cannibalism.

Principal Terms

Ecosystem: a community of organisms in relation to each other and their physical environment

Endocannibalism: a form of human cannibalism in which members of a related group eat their own dead

Exocannibalism: a form of human cannibalism in which unrelated humans are eaten

Bibliography

Brown, Paula, and Donald Tuzin, eds. The Ethnography of Cannibalism. Washington, D.C.: The Society for Psychological Anthropology, 1983. A collection of essays from a 1980 symposium by the Society for Psychological Anthropology.

Elgar, Mark A., and Bernard J. Crespi, eds. Cannibalism: Ecology and Evolution Among Diverse Taxa. New York: Oxford University Press, 1992. Standard study of the role of cannibalism in animal evolution.

Goldman, Laurence R., ed. The Anthropology of Cannibalism. Westport, Conn.: Bergin and Garvey, 1999. Provides general textbook-style information

Klitzman, Robert. The Trembling Mountain: A Personal Account of Kuru, Cannibals, and Mad Cow Disease. New York: Plenum Trade, 1998. Tells of the author’s attempt to show, after months of field study, the relation between endocannibalism and Kuru (a brain disease).

Price, Michael. "Why Don't We Eat Each Other for Dinner? Too Few Calories, Says New Cannibalism Study." Science, 6 Apr. 2017, www.sciencemag.org/news/2017/04/why-don-t-we-eat-each-other-dinner-too-few-calories-says-new-cannibalism-study. Accessed 31 Jan. 2018.

Raffaele, Paul. “Sleeping With Cannibals.” Smithsonian Magazine, www.smithsonianmag.com/travel/sleeping-with-cannibals-128958913. Accessed 30 June 2023.

Schutt, Bill. Cannibalism: A Perfectly Natural History. Algonquin Books of Chapel Hill, 2017.

Williams, Leoma. “Cannibal Animals: 10 Animals That Eat Their Own Kind.” BBC Wildlife Magazine, 14 February 2022, www.discoverwildlife.com/animal-facts/cannibal-animals-creatures-that-eat-their-own-kind. Accessed 30 June 2023.