Overview

• 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.