Studying ancient children’s teeth to reveal future

Associate Professor Tanya Smith. Image: Jeff Camden

Human evolutionary biologist Professor Tanya Smith has been awarded an Australian Research Council Future Fellowship worth $1,075,728 to investigate prehistoric human population growth by analysing the teeth of ancient children.

Professor Smith, from the Australian Research Centre for Human Evolution and the Griffith Centre for Social and Cultural Research, has spent her career researching teeth and what they can tell us about human evolution.

She penned and illustrated a 2018 popular science book on the topic called The Tales Teeth Tell, attracting favourable reviews from Nature and The Washington Post.

Her ARC project aims to investigate prehistoric human population growth by documenting nursing behaviour, developmental stress, and fine-scaled climate variation directly from the teeth of ancient children.

“Teeth have these amazing records locked inside them,” she says.

“When we grow our teeth, we create detailed childhood chronicles, and they’re so mineralized that they’re almost fossils already,” she says. “If an individual died before it stopped forming its teeth, we can count daily growth lines and figure out how old that person was.”

Teeth also carry special chemical signatures of mother’s milk and the local environment. By teaming up with elemental chemists and geoscientists in America and Australia, Professor Smith’s team will use cutting-edge analytical techniques to recover nursing histories in prehistoric children, as well as weekly climate record during their first few years of life.

“Compared to other primates, humans are very unusual because they nurse their infants for a shorter period of time than say, a chimpanzee or an orangutan. The reason this is important is that it means human mothers can have more babies in the same period of time.

“There’s been a theory that, in the past, hunters and gatherers – humans that weren’t growing their food, would have nursed their infants longer. So, we’re trying to test this question to work out whether there were fundamental changes with the agricultural revolution.

“Our diet has changed radically – not just with agriculture, but also the industrial revolution yielding soft, heavily-processed foods. Having modern, energy-dense meals readily available has been a developmental game-changer for expecting mothers and their little ones!”

Professor Smith was one of four Griffith University researchers to share in $3,824,013 in ARC Future Fellowship Funding.

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