How Mammal Ancestors Came About as the First Reptiles Roamed the Earth, Science Explains

The earliest mammal ancestors began their rise when proto-reptiles were starting their eventual domination about 230 million years ago.

When reptiles were beginning their reign as top animals, mammals were evolving characteristics of warm-bloodedness that would lead to survival when the disaster in the Cretaceous mass extinction event struck.

Mammal's Ability To Generate Heat From Within

The key to mammalian dominance is evolving endothermy, which enables an animal to stabilize its interior temperature even if it's cold outside. Without it, endotherms would not be found even on the icy fringes of Antarctica., reported Science Alert.

But how this characteristic of keeping a steady body temperature is something arcane, even to evolutionary biologists, is perplexing.

According to a study led by Lisbon University paleontologist Ricardo Araujo, it began 230 million years ago during the Late Triassic epoch. It was the beginning of the most incredible beasts the world had ever seen.

The examination of fossils was not in the blood but in the inner ears of protean mammalian progenitors. Researchers thought the inner ear was important for body temperature regulation, but they were wrong. Body temperature is controlled by the viscous and runny fluid inside the inner canals, noted News Achieve.

Before this hypothesis, it was thought the loops of the inner ear that held fluid sensed the position of the head. It controls balance, vision, and assisted movement in the body.

Fossilized Inner Ear Holds Clues of Evolutionary Trait

Romain David, study author, and paleontologist, an expert in the biomechanics of ear canal structures, said now they know these inner ear structures were thought to deal with movement in mammal ancestors when the first reptiles existed, but not so, citing Spidi news.

Several approaches were taken to determine when endothermy first appeared in ancient mammals and birds. In the study, links to metabolism, oxygen intake, body hair, and normal body heat were not exactly shown to have precise results.

The method used to understand the inner ear and how it affects internal temperature has been examined in 360 living and extinct vertebrates before checking fossils.

One conclusion is that the inner canals of mammals had to adapt new shapes to deal with runnier fluids. Detecting such earth structures is a clue to evolving a warmer body temperature.

More analysis was done on extinct species that mammals came from; they had smaller ear canals and narrower ducts compared to cold-blooded ones. Changes show that these ear structures raised body heat from 5 to 9 degrees Celsius.

The evidence from fossilized ears estimated that it took less than one million years to develop endothermic characteristics.

Surviving the Triassic Climate

The climate was getting cold fast when proto-mammals were getting fur to survive environmental changes. Araújo and colleagues point out how heat regulation saved mammal ancestors and mention Nature.

He added it was triggered by many changes, like metabolism and getting fur to survive. Ectothermic animals, like mammals and avians, might not be the only reason for dominance today. Some researchers contend that dinosaurs were endothermic, not ectothermic, like modern birds and mammals.

Another Yale University molecular paleobiologist, Jasmina Wiemann, and colleagues point out that it was more than warm-bloodedness that allowed non-reptilians to branch out after the great extinction of the Cretaceous. There's a lot more hidden in the depths of time.

Our mammal ancestors had to develop endothermy as the first reptiles began the Age of Dinosaurs, becoming the dominant animal eons later.