Cannibalism: A Perfectly Natural History

by Bill Schutt

scientists estimate that for every million eggs produced by an Atlantic cod (Gadus morhua), approximately one egg will result in an adult fish.

parental care occurs in only around 20 percent of the 420 families of bony fishes

even in the 90 or so piscine families where parental care does occur, filial cannibalism is an extremely common practice, and here the primary reason has to do with who is doing the babysitting.

Mouthbrooding is a common form of behavior in cichlids. Typically, it refers to post-spawning behavior in which parents (usually females) hold their brood of fertilized eggs inside their mouths until they hatch and sometimes even after that. This provides the eggs and fry with a haven from predators, a point commonly portrayed in crowd-pleasing nature videos that depict young fish darting back into their parent’s mouth at the first sign of danger. Conspicuously missing from these lighthearted reports is the fact that parents holding a mouthful of eggs usually eat a considerable portion of them, and sometimes the entire brood. Also destined for the digital equivalent of the cutting room floor are shots showing male cichlids fertilizing the eggs in the females’ mouths, always a difficult topic to explain during family TV time.

With Christopher Columbus acting as a poster boy, applying the cannibal tag justified the condemnation and, if necessary, the eradication of anyone accused of engaging in this ultimate of taboos—a practice whose validity (Arens was quick to point out) was always unsupported by anything resembling firsthand evidence.