ome 250 million years ago, in the time when life was recovering from
The greatest mass extinction of all time, the Permian-Triassic mass extinction 250 million years ago, killed 95 percent of life, and the very few survivors faced a turbulent world, repeatedly hit by ice ages, rapid warming and ocean acidification cycles.
Through all of that, two main groups of tetrapods survived; the synapsids and archosaurs, ancestors of mammals and birds. And
a new study find that the ancestors of both mammals and birds became warm-blooded at the same time.