[antognini]

That may have been true for agricultural societies, but it doesn't sound right for hunter gatherers (at least from my memory of an anthropology class I took). Many hunter gatherer societies have strong postpartum taboos and space children at least three years apart.

[positr0n]

I thought babies would breast feed for 3 to 6 years. Even today the WHO recommends 2+ years.

[drainyard]

WHO recommends _up to_ 2 years. After 6 months in addition to other nutrition.