Our ancestors’ prenatal growth sped up after we split from chimps

Carissa Wong is a person.

Estimates based on fossil teeth suggest that ancient hominids had high growth rates.

The fastest ape in the hominid family, the gorilla, has a rate of 8.2 grams per day, while the human fetus grows by around 11 grams per day.

The evolution of the modern human species is thought to have begun around 200,000 to 300,000 years ago.

Fossilised pelvises and the rare remains of infants have been used in the past by researchers.

Monson and her colleagues found that the ratio of the first and third teeth is related to the growth rate of the fetus.

A group of researchers built a mathematical model that could predict the growth rate of apes and monkeys.

The model was used to predict the growth of 13 hominid species. After our ancestors split from Chimpanzees around 5 to 6 million years ago, they became more similar to modern humans than other apes, according to this.

Monson and her team are trying to understand why the growth rate may be related to the length of the tooth. She acknowledges that there is a chance that extrapolating growth from bones isn't reliable. She says that since we don't have a time machine, we can't compare our reconstructions with the values of the past.

There has been an increase in brain size among hominids. Monson says that their reconstructions align with many other lines of evidence.

According to Anna Warrener at the University of Colorado Denver, the authors found that human-like growth rates emerged less than one million years ago.

She says teeth are frequently found in the fossil record and would be a great tool for such evaluations in the future.

The study is extremely important. Due to poor preservation, fetal growth rates can't be accessed. Patrick Mahoney is a professor at the University of Kent, UK.

The journal is called PNAS and is published on 10.1073/pnas.

The revolution in archaeology and human evolution is covered in Our Human Story.