Short answers, pulled from the story.
The word "cannibal" derives from the Spanish caníbal or caríbal, originally a name variant for the Kalinago, also called the Island Caribs, a people from the West Indies said to have eaten human flesh. The older term for the practice is anthropophagy, meaning "eating humans."
Anthropologists distinguish three principal types: institutionalized cannibalism (accepted within a culture), survival cannibalism (driven by famine, shipwreck, or siege), and cannibalism as psychopathology (committed by isolated individuals their societies regard as criminal). Within institutionalized cannibalism, endocannibalism involves consuming members of one's own community, often in funerary rites, while exocannibalism involves consuming outsiders, frequently enemies killed in war.
Yes. Medicinal cannibalism, the ingestion of human body parts as a supposed medicine or tonic, was widely practised in Europe from the 16th to 18th centuries, with early records going back to the first century CE. The practice reached its height during the 17th century and continued in some cases into the second half of the 19th century.
Archaeologist James Cole calculated that all edible parts of a typical adult man yield roughly 126,000 kilocalories, comparable to animals of similar size. At an adult daily energy need of about 2,400 kilocalories, a male body could theoretically sustain 25 men for just over two days. Cole noted that large megafauna such as mammoths or bison offered a far better caloric return for prehistoric hunters due to their much greater body mass.
The Fore people practised mortuary cannibalism, consuming deceased members of their community as part of funerary rites. This spread kuru, a fatal prion disease transmissible through infected brain tissue. By the time researchers identified the cause, the Fore had already ceased the practice.
Romanian philosopher Catalin Avramescu identified the doctrine of bodily resurrection as the key factor. If the dead are to be raised bodily, and if a body is composed of what a person has eaten, then consuming human flesh creates a theological paradox: the eaten flesh would have to exist twice to allow both the eater and the eaten to be resurrected. Christian thinkers including Athenagoras of Athens and Thomas Aquinas wrestled with this problem and concluded that divine power could resolve it, but the concern made cannibalism appear as a challenge to a central Christian doctrine.