About 200 million years ago, furry, little egg-laying creatures evolved the ability to feed their offspring with a secretion from special glands: milk. Their evolutionary journey continued, and by about 160 million years ago, the first mammals with a real placenta had come into being. Instead o...
Source: [Phys.org](https://phys.org/news/2026-09-early-mammals-werent-loners-pairs.html)