Scientists discover rare 'Jurassic' fossil of creature from 166 million years ago, learn secrets of mammals' evolution

Mammals are a group of warm-blooded vertebrates that give birth to live young and feed them with milk. Known as one of the most adaptable animals on the Earth, mammals are found on every continent and in every range in size, be it tiny bumblebee bats, to humans, or giant blue whales.

For decades, scientists have been trying to track the evolution of mammals to understand how they became among the most successful animals on the planet. Recently, scientists discovered two rare fossils in Scotland's Isle of Sky that can provide crucial information about the evolution of mammals on Earth.

About the discovery

For decades, a Jurassic era mammal, Krusatodon, has been at the centre of attention for the research fraternity as it is supposed to be one of the first to roam earth, alongside dinosaurs. So far, only a handful of fossils of the primitive shrew-like mammal have been found. Out of them are two exceptionally complete skeletons, one of a juvenile creature and another of an adult. The two fossils were discovered from Skye in Scotland. What makes Krusatodon stand apart from modern small mammals is its long life span.

Why is the rare fossil discovery important?

According to the BBC, studying these fossils of the earliest mammals can help scientists understand the factors that helped them become some of the most adaptable animals on Earth. The researchers used hi-tech X-ray imaging to peer through rock and study growth patterns in the teeth of the two fossil fuels.

The study of a juvenile mammal's fossil reveals that it was weaning, replacing teeth at an estimated age of 2 years, which is unusual compared to modern-day small mammals, Dr Elsa Panciroli, Associate Researcher of Palaeobiology at National Museums Scotland, told BBC News.

Small mammals present on Earth today have much shorter lifespans, sometimes as small as 12 months, which is in complete contrast with the ancient mammal discovered by scientists in Scotland.