i'm reading Cannibalism: A Perfectly Natural History right now. my own notes, so take with a grain of salt, some fava beans and a nice chianti.
A N I M A L S ('conspecifics' = animals of the same species)
reasons:
- not recognising their conspecifics
- stressful environments, incl. lack of other food
- prioritizing fewer but strong over more but weaker offspring
types:
- filial cannibalism (eating one's own offspring)
- producing eggs just for food (insects, fish)
- eating eggs for food because there's so many anyway (fish)
- eating eggs as food while protecting the eggs (fish)
- heterocannibalism (eating unrelated conspecifics)
- sibling cannibalism
- in-utero ('intrauterine') (sand tiger sharks)
- oophagy (eating siblings who are still in eggs)
- sacrificing one offspring to feed the others (birds?)
- sacrificing oneself as food for one's young (black lace-weaver spider)
- sexual cannibalism (of the smaller partner, which in invertebrates is mostly the male)
wip!