Saturday, September 03, 2022

Prehistoric mammals got ahead as they grew up twice as fast after the dinosaurs were wiped from earth
An artist's impression of a Pantolambda bathmodon, 
which grew to about the size of a sheep. 
Photo: H Sharpe / PA


Lucinda Cameron
September 01 2022 

Some prehistoric mammals were born almost independent and grew up twice as fast as today’s mammals, giving them an edge after dinosaurs became extinct, a new study has suggested.

Scientists used dental analysis to uncover the life history of Pantolambda bathmodon – a member of the earliest known group of herbivore in the post-dinosaur era.

It grew to about the size of a sheep.

The findings, published in the weekly science journal Nature, suggest that Pantolambda bathmodon mothers were pregnant for just under seven months and gave birth to single, well-developed babies which had a full mouthful of teeth.

Their babies, probably mobile from day one, suckled for only one to two months before they became fully independent.

An international team led by the University of Edinburgh in collaboration with the University of St Andrews, Carnegie Museum of Natural History and New Mexico Museum of Natural History and Science was involved in the research.

“When the asteroid knocked off the dinosaurs 66 million years ago, some mammals survived and they ballooned in size really quickly to fill the ecological niches vacated by T-rex and Triceratops, and other giant dinosaurs,” Professor Steve Brusatte, from the school of geosciences at the University of Edinburgh, said.

“Being able to produce large babies – which matured for several months in the womb before being born – helped mammals transform from the humble mouse-sized ancestors that lived with dinosaurs to the vast array of species, from humans to elephants to whales, that are around today.”

The scientists found chemical changes in the teeth showed major transitions in the early life of the creatures, including high levels of zinc deposited at birth, and enrichment with barium during the suckling period.

Although the gestation time inferred from the research matches that of today’s similarly-sized mammals, this early mammal is found to have lived and died more rapidly by comparison.

The data shows that Pantolambda bathmodon were independent and ready to mate before their first birthday.

The creatures also lived only three to four years on average, whereas most mammals of similar size today live 20 years or more.

“Our research opens the most detailed window to date into the daily lives of extinct mammals,” said lead author Dr Gregory Funston, who is Royal Society Newton International Fellow at the University of Edinburgh and is currently based at the Royal Ontario Museum, Toronto.

“This unprecedented level of detail shows the kinds of lifestyles that make placental mammals special, evolved early in their evolutionary history.

“We think that their babies’ longer gestation period could have nurtured large body sizes faster than other mammals, which may be why they became the dominant mammals of today.”

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