Cannibalism Surprisingly Normal in the Natural World, Scientist Discovers

Few things are more disturbing -- and more taboo -- than cannibalism. Killing fellow human beings is one thing, but eating them is almost unthinkable, it's the stuff that horror movies are made of.

In his new book entitled "Cannibalism: A Perfectly Natural History," Bill Schutt explained how this behavior that's often seen and portrayed as deviant and macabre actually occurs quite commonly in the natural world.

According to a report from the Washington Post, the zoologist from the American Museum of National History scoured the world for all kinds of situations when individuals of the same species were moved to devour each other.

Schutt defined cannibalism as "consuming any part of an individual of the same species, whether you kill that individual or whether that individual is dead and you come upon him scavenging, or something else."

The threat of starvation is one motive that even humans generally accept, but there are many instances in the animal kingdom when the creatures regularly practice some form of cannibalism.

In some species, it's actually part of parental care such as in the case of spiders and snails who lay unfertilized eggs to feed their babies. Mothers even take it one step further by allowing the spiderlings to eat her if their food runs out. Birds employ what Schutt calls the "lifeboat strategy" where older or larger birds consume their smaller and meeker siblings when there aren't enough food.

On the other hand, large cats occasionally eat the cubs of females in a newly acquired pride so that the mothers will be more receptive to their advances.

Read: Shocking Video: Chimpanzees Conspire, Kill, Cannibalize Former Leader

Because it is such taboo behavior in modern society, stories of cannibalism rarely get discussed beyond criminal cannibalism and survival stories. However, Schutt explained that ritualistic cannibalism has been part of society throughout history.

NPR notes that Certain cultures such as the Fore tribe in Papua New Guinea used to eat their deceased tribe members as part of the funeral rites. For hundreds of years, eating different body parts were considered an acceptable method of medicine in Europe, according to the Smithsonian Magazine. From human skulls to blood and fat, Europeans in the 16th and 17th centuries consumed flesh to treat various ailments.

Famine has also driven men and women to eat human flesh in the past. A report from National Geographic revealed that during China's Cultural Revolution, families ended up trading their children so they wouldn't have to eat their own. Schutt warned that if climate change persists and food supply disappears, it's possible famine-related cannibalism could arise again.

"In the West we have a layer of culture that prevents us from cannibalizing," he said. "But we know that cannibalism has taken place with humans during famine. And with all of the changes that are taking place due to global warming, like desertification, it's not a stretch that cannibalism might occur if large groups of people were suddenly without food."

Read: The Gruesome Tale of the Franklin Expedition: Cannibalism in Doomed Journey Proven Real