Jurassic Mammals Grew Differently from Modern Relatives, Study Finds

New X-ray imaging of fossil teeth reveals slower growth and longer lifespans in ancient mammals compared to today's small mammals.

Researchers used synchrotron X-ray tomography to analyze growth rings in fossilized teeth from Jurassic mammals.
The study found early mammals had slower growth rates and longer lifespans than modern small mammals.
These ancient mammals took several years to reach sexual maturity, unlike today's small mammals that mature within months.
The research challenges previous assumptions about the life history of early mammals.
Findings suggest that key mammalian traits evolved gradually over millions of years.