natural weaning

so no animal milk for cal yet
am thinking of introducing a small amount starting at 16mths.
we'll see
i don't want him to wean early
came across an interesting bit of research on the age of natural weaning in humans

http://www.kathydettwyler.org/detwean.html

"In societies where children are allowed to nurse "as long as they want" they usually self-wean, with no arguments or emotional trauma, between 3 and 4 years of age."