Modern cats are larger than ancient horses that lived 50 million years ago. This conclusion was made by American scientists on the basis of the analysis of the teeth of ancient horses, they made a conclusion that they were little ones. The progenitors of modern horses weighed only four kilograms, and the size of the miniature horses looked like modern home cats.
The teeth, by which the size of the ancient dwarf horses was determined, belonged to the animals of the long-extinct species Sifrhirpus sandrae. They lived about 56 million years ago during the so-called period of the late Paleocene thermal maximum. At that time, a large release of carbon dioxide into the atmosphere was observed, which led to an increase in the ambient temperature by five to six degrees. During this period, due to the high temperature, more than a third of all milk-feeding on Earth significantly decreased in size.
The horses of the fossil species Sifrhirpus sandrae became less by a third, and their weight rarely exceeded 4 kilograms. Later, with a decrease in temperature, the horses began to grow and gain weight. After 50 thousand years, they became almost two times more and already weighed about seven kilograms.