Monkey teeth help reveal Neanderthal weaning

Monkey teeth help reveal Neanderthal weaning

May 24, 2013 — Most modern human mothers wean their babies much earlier than our closest primate relatives. But what about our extinct relatives, the Neanderthals?

A team of U.S. and Australian researchers reports in the journal Nature May 22 that they can now use fossil teeth to calculate when a Neanderthal baby was weaned. The new technique is based in part on knowledge gained from studies of teeth from human infants and from monkeys at the California National Primate Research Center at the University of California, Davis.

Using the new technique, the researchers concluded that at least one Neanderthal baby was weaned at much the same age as most modern humans.

Just as tree rings record the environment in which a tree grew, traces of barium in the layers of a primate tooth can tell the story of when an infant was exclusively milk-fed, when supplemental food started, and at what age it was weaned, said Katie Hinde, professor of human evolutionary biology at Harvard University and an affiliate scientist at the UC Davis Primate Center. Hinde directs the Comparative Lactation Laboratory at Harvard and has conducted a three-year study of lactation, weaning and behavior among rhesus macaques at UC Davis.

The team was able to determine exact timing of birth, when the infant was fed exclusively on mother's milk, and the weaning process, from mineral traces in teeth. By studying monkey teeth and comparing them to center records, they could show that the technique was accurate almost to the day.

After validating the technique with monkeys, the scientists applied it to human teeth and a Neanderthal tooth. They found that the Neanderthal baby was fed exclusively on mother's milk for seven months, followed by seven months of supplementation -- a similar pattern to present-day humans. The technique opens up extensive opportunities to further investigate lactation in fossils and museum collections of primate teeth.

Although there is some variation among human cultures, the accelerated transition to foods other than mother's milk is thought to have emerged in our ancestral history due, in part, to more cooperative infant care and access to a more nutritious diet, Hinde said. Shorter lactation periods could mean shorter gaps between pregnancies and a higher rate of reproduction. However, there has been much debate about when our ancestors evolved accelerated weaning.

For the past few decades researchers have relied on tooth eruption age as a direct proxy for weaning age. Yet recent investigations of wild chimpanzees have shown that the first molar eruption occurs toward the end of weaning.

"By applying these new techniques to primate teeth in museum collections, we can more precisely assess maternal investment across individuals within species, as well as life history evolution among species," Hinde said.

Authors in addition to Hinde were: Christine Austin and Manish Arora, Icahn School of Medicine at Mount Sinai, New York, Harvard School of Public Health, and University of Sydney, Australia; Tanya Smith, Harvard University; Asa Bradman and Brenda Eskenazi, UC Berkeley; Renaud Joannes-Boyau, Southern Cross University, Lismore, Australia; David Bishop, Dominic Hare and Philip Doble, University of Technology Sydney, Australia.

The work was funded by the U.S. Environmental Protection Agency, U.S. National Institute of Environmental Health Sciences, U.S. National Science Foundation, Australian National Health and Medical Research Council, Australian Research Council and Harvard University.

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.

SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc

we are focus on the following fields,and hope we can help you.

CRGH0805J4K7 CRGH0805J4K3 CRGH0805J47R CRGH0805J47K CRGH0805J470R CRGH0805J470K CRGH0805J43R CRGH0805J43K CRGH0805J430R CRGH0805J430K CRGH0805J3R9 CRGH0805J3R6 CRGH0805J3R3 CRGH0805J3R0 CRGH0805J3M9 CRGH0805J3M6 CRGH1206F107K CRGH1206F105R CRGH1206F105K CRGH1206F102R CRGH1206F102K CRGH1206F100R CRGH1206F100K CRGH0805J9R1 CRGH0805J9M1 CRGH0805J9K1 CRGH0805J91R CRGH0805J91K CRGH0805J910R CRGH0805J910K CRGH0805J8R2 CRGH0805J8M2 CRGH0805J8K2 CRGH0805J82R CRGH0805J82K CRGH0805J820R CRGH0805J820K CRGH0805J7R5 CRGH0805J7M5 CRGH0805J7K5
http://www.suvsystem.com/a/1579.aspx