Why this should be the case is not fully understood.
It may be related to the trading of bird of paradise plumes between the highlands and the coast. Read more This stone pestle was found over 100 years ago by gold miners in the banks of the Aikora River in Oro in Papua New Guinea.
Birds are still hugely important omens for people in New Guinea, their flight paths checked anxiously for whether they bring good luck or misfortune.
We might think that we compartmentalise food and faith, supermarket and church or mosque, but for us, too, just like the New Guinea farmers who used this pestle, coming together at the dinner table underpins all our social interactions and life ceremonies. Read more New Guinea has one of the oldest histories of food production in the world.
The largest cluster of finds comes from the shores of a former inland sea, which was in-filled about 4,000 years ago.
Curiously most of the birds sculpted on the handle tops of the pestles found in this cluster have their wings folded rather than raised like this stone bird pestle.
Soon after our species, Homo sapiens, arrived here around 40,000 years ago as part of their expansion out of Africa, they began exploiting plants like yams and taro.
Studies of fossil pollen show that they burnt forest to encourage the growth of these plants.
The stone pestles and mortars are always found in areas where taro, an edible starchy tuber (or plant stem), can be grown.
People in Papua New Guinea learnt how to grow crops 9000 years ago.
Papua New Guinea was one of seven locations where farming independently developed after the last Ice Age.
It may be related to the trading of bird of paradise plumes between the highlands and the coast.
New Guinea has one of the oldest histories of food production in the world.