Mammals can produce their own body heat and control their body temperature. This process is known as heat absorption or hot bleeding.
Scientists think it may be the reason why mammals may dominate nearly everyone environmental system. Warm-blooded mammals are more active than cold-blooded animals. They can live in different environments, from the frozen arctic to the boiling desert. And they multiply faster.
Rarely are the soft tissues that may give information about cold or warm bleeding saved in fossils. Therefore, paleontologists, or experts in the study of fossils, do not know exactly when mammals evolved into warm-blooded creatures.
A group of scientists tried to answer this question in a study recently published in temper nature.
Ricardo Araujo is a paleontologist at the University of Lisbon. Araujo and a group of researchers have proposed that the shape and size of the inner ear structures called canals can be used to study body temperature.
The movement of fluid through the ear canals helps the body maintain balance and movement. This fluid in cold-blooded animals is colder and thicker, which means that wider channels are needed. Warm-blooded animals have less ear fluid and smaller canals.
The research team suggested that as the animals’ body temperature increased and the animals’ activity increased, the shape and size of the ear canals changed to maintain balance and movement.
The researchers compared ear canals in 341 animals. They said the ear canals showed that hemorrhagic, or endothermic, bleeding appeared about 233 million years ago, millions of years later than some earlier estimates.
Araujo said, “Endothermy is the definition of Property of mammals, including humans. Having a high body temperature Organize All of our actions and behaviors.
But the first creatures that showed warm blood were not officially considered mammals. These ancient animals were known as mammaliamorph synapsids Features related to mammals. The researchers said the first true mammals appeared about 30 million years ago.
The importance of being warm-blooded
Ken Angelcic of Chicago’s Field Museum is co-leader of the study. He said, “Given how important a heat absorbent is to many Ways From the outline of the body, the physiology and lifestyle of modern mammals, when evolved In our ancient ancestors it was a really important unresolved question…”
Endothermy evolved at a time when important elements of the mammalian body diagram were falling into place, including changes to the spine, respiratory system, and hearing organ.
The presence of warm-blooded animals also helped mammals at an important evolutionary moment when dinosaurs and flying reptiles first appeared on Earth. Mammals took over after the mass extinction of the dinosaurs 66 million years ago. Among the animals of today, mammals and birds are warm-blooded.
“Maybe it is out of reachBut it is interesting to think that the emergence of endothermic in our ancestors may have eventually led to the construction of the Giza pyramids or the development of the smartphone.”
“Had our ancestors not become independent of environmental temperatures, these human accomplishments would probably not have been possible.”
I’m John Russell.
John Russell adapted this story for VOA Learning English based on Nature, Scientific American and Reuters news reports.
The words in this story
environmental system – n. Everything exists in a certain environment
keep – Fifth. To keep (something) in its original condition or in good condition
fossil – n. Something (such as a leaf, a skeleton, or a footprint) from a plant or animal that lived in ancient times and can be seen in some rocks
Property – n. An important or interesting part, quality, capacity, etc.
to organize – Fifth. to set or adjust an amount, degree, or rate (something)
Trait – n. An adjective that makes a person or thing different from another
side – n. part of something
has evolved – Fifth. to change or evolve slowly, often to a better, more complex, or more advanced state: to evolve through the process of evolution
out of reach – characteristic It is not likely to happen or be true