Scientists, along with researchers from the University of Nebraska and University of Florida, found something unique; they discovered a relation between temperature of the environment and the size of the body of mammals. They followed the evolution of Sifrhippus Sandrae, which is the earliest known horse.
About Sifrhippus Sandrae:
This horse survived in the North America’s forest around 56 million years ago. Such horses also existed during 175,000 year time interval called Paleocene-Eocene Thermal Maximum (PETM). When the temperature of the globe increased by 10 degrees Fahrenheit during the mentioned period, around 1/3rd of species of mammals went through a decrease in their sizes.
The scientists and researchers analyzed the size as well as the chemistry of the fossil teeth of Sifrhippus; they were discovered in Wyoming. The team had to find out how the teeth grew due to the change in environment.
The results of the study and research are published in Science, an international journal. They show that S. Sandrae weighed around 12 pounds only, which is 5.6kgs. This was their initial weight. Later, they shrank by almost 30% and turned to be of a housecat’s size, which is around 8.5 pounds or 4kgs. This was at the beginning of the PETM when warmth touched the globe.
On the other hand, as soon as the species were touched by the calmness of winter, the species expanded or grew to weigh 15 pounds or 7kgs.
Along with the above mentioned conclusions or results, the researchers also found out that the levels of carbon dioxide were related to aridity. Temperature was definitely one of the things that influenced the size of the body in the mammals earlier.
The scientists state that the PETM is quite important since it takes you to the history and evolution of several major mammals.