AI Insight
Fossil footprints discovered in Brazil indicate that a mammal roughly the size of a modern cougar lived during the Mesozoic Era, walking alongside dinosaurs. This finding challenges the traditional view that all mammals during the age of dinosaurs were small, shrew-like creatures. The evidence suggests that some early mammalian species achieved substantial body sizes earlier in their evolutionary history than previously believed.
Why it matters
This discovery revises our understanding of mammalian evolution during the Mesozoic Era, demonstrating that ecological niches for larger mammals existed even when dinosaurs dominated terrestrial ecosystems. It suggests that early mammalian diversification in body size and ecological roles occurred millions of years earlier than conventional models proposed.
Understand the Science
Don’t think of all Mesozoic mammals as meek and tiny—alongside the terrible lizards, some were giants in their own right