Almost everything about Neanderthal behaviour remains controversial. From their physiology, Neanderthals are presumed to have been omnivores, but animal protein formed the majority of their dietary protein, showing them to have been carnivorous apex predators and not scavengers. Although very little is known of their social organization, it appears patrilines would make up the nucleus of the tribe, and women would seek out partners in neighbouring tribes once reaching adolescence, presumably to avoid inbreeding. The men would pass knowledge and customs down from fathers to sons. Neanderthal women appear to heavily skew physically impressive neanderthal men, hinting that neanderthal men would compete with each other and polyamorous relationships would emerge.