斷奶是任何哺乳動(dòng)物（尤其是人類）生命中的一個(gè)關(guān)鍵時(shí)期,，斷奶較早可以讓婦女在較短時(shí)間內(nèi)生更多孩子。因此,，早期斷奶的形成有可能對(duì)“智人”的演化和成功產(chǎn)生過(guò)深遠(yuǎn)影響,。此前，人們一直不能比較準(zhǔn)確地從化石確定斷奶的年齡,，但Manish Arora及其同事在這項(xiàng)研究中發(fā)現(xiàn)，牙釉質(zhì)中的鋇-鈣比例是人類和獼猴哺乳期的一個(gè)可靠標(biāo)記,。
鋇含量在哺乳期升高,，在斷奶時(shí)突然降低。對(duì)來(lái)自一個(gè)保存完好的比利時(shí)“尼安德特人”的一顆牙齒所做的研究,，顯示了完全進(jìn)行母乳喂養(yǎng)（哺乳）的時(shí)期和接受混合飲食的時(shí)期的時(shí)間長(zhǎng)短以及一個(gè)非常早的斷奶年齡——只有大約14個(gè)月,。（生物谷Bioon.com）
生物谷推薦英文摘要：
Nature doi:10.1038/nature12169
Barium distributions in teeth reveal early-life dietary transitions in primates
Christine Austin, Tanya M. Smith, Asa Bradman, Katie Hinde, Renaud Joannes-Boyau, David Bishop, Dominic J. Hare, Philip Doble, Brenda Eskenazi & Manish Arora
Early-life dietary transitions reflect fundamental aspects of primate evolution and are important determinants of health in contemporary human populations. Weaning is critical to developmental and reproductive rates; early weaning can have detrimental health effects but enables shorter inter-birth intervals, which influences population growth. Uncovering early-life dietary history in fossils is hampered by the absence of prospectively validated biomarkers that are not modified during fossilization. Here we show that large dietary shifts in early life manifest as compositional variations in dental tissues. Teeth from human children and captive macaques, with prospectively recorded diet histories, demonstrate that barium (Ba) distributions accurately reflect dietary transitions from the introduction of mother’s milk through the weaning process. We also document dietary transitions in a Middle Palaeolithic juvenile Neanderthal, which shows a pattern of exclusive breastfeeding for seven months, followed by seven months of supplementation. After this point, Ba levels in enamel returned to baseline prenatal levels, indicating an abrupt cessation of breastfeeding at 1.2?years of age. Integration of Ba spatial distributions and histological mapping of tooth formation enables novel studies of the evolution of human life history, dietary ontogeny in wild primates, and human health investigations through accurate reconstructions of breastfeeding history.
