All mammals are warm-blooded, meaning that their bodies maintain their temperatures internally and independently of the temperature of their surroundings. This physiological feature is imperative in allowing mammals to survive and to stay toasty through the coldest conditions. But, despite its importance, the best way to determine when warm-bloodedness initially developed remains a mystery.
Recent research in Nature presents a new method for solving this mystery, stating that the size of the tiny canals in an animal’s ears can enable scientists to pin down the start of warm-bloodedness. Plus, in addition to proposing a long-sought-after solution to this problem of methodology, the research also reveals that the transition to warm-bloodedness probably took place around 233 million years ago, much more recently and much more quickly than previously believed.
To scientists, it has seemed almost impossible to identify when the ancestors of modern-day mammals developed their warm-bloodedness, officially known as endothermy. ...
