Jurassic mammals outlived modern ones by several years, study reveals

Early mammals from the Jurassic era, when dinosaurs ruled the Earth, had much longer lifespans than their modern counterparts. These findings were published in the prestigious journal "Science Advances."

Researchers conducted a detailed analysis of early mammal fossils from the Jurassic period. This analysis revealed that these animals enjoyed relatively long lives. A key element of the research was the study of growth rings in the teeth, providing scientists with valuable information about these mammals' lifespan and growth rates. Additionally, this analysis helped determine the age at which these animals reached sexual maturity.

The research, published on the University of Bonn's website, was conducted by teams from the University of Bonn in Germany and Queen Mary University of London in the United Kingdom.

As part of this research, scientists analyzed fossils of various Jurassic mammal species and their predecessors. These fossils were found in different locations, such as Portugal, Wales, and Oxfordshire in the United Kingdom. Among the analyzed species were Dryolestes, which reached sexual maturity at four years, and Haldanodon, which lived between 11 and 14 years. These findings date back to between 200 million and 150 million years ago.

"Never before have we been able to reconstruct the growth patterns of these early mammals in such detail," from Queen Mary University of London.

The team utilized synchrotron X-ray tomography. In this technique, electrons are accelerated to a speed close to the speed of light, which sets it apart from traditional X-ray imaging.

This technique allowed scientists to obtain images of much higher quality than those achievable with conventional X-ray microtomography.

Scientists visualized tiny growth rings in the bone tissue that anchors teeth to the jaw. "Counting the rings and analyzing their thickness and texture enabled us to reconstruct the growth patterns and lifespans of these extinct animals," explains Prof. Thomas Martin from the University of Bonn.

The research showed that the first signs of growth patterns characteristic of modern mammals, such as accelerated growth during adolescence, began to appear around 150 million years ago.

Early mammals grew much slower than their modern counterparts but lived much longer. Their lifespans ranged from eight to fourteen years, while today’s small mammals, such as mice, typically live only one or two years. Early mammals, however, took several years to reach sexual maturity, whereas their modern counterparts reach it in just a few months.