Feather Insulation Predicted Avian Survival

CT scans of a 66‑million‑year‑old coprolite show feathers from a diving bird that combined waterproof outer plumes with primitive fuzzy body feathers. The authors argue those mixed, less‑insulating feathers made some Cretaceous birds vulnerable to post‑impact thermal and environmental stress, while lineages with more advanced insulating feathers (the ancestors of modern birds) were more likely to survive. — Identifying specific anatomical traits that determined survivorship in mass extinctions changes how we think about vulnerability, adaptation, and the deep drivers of modern biodiversity — with implications for evolutionary theory and public understanding of extinction risk.