STATES CHRONICLE – In Texas were recently discovered some fossils of bear dogs, a species of carnivores. These fragmentary fossils were revealed 30 years ago in southern Texas. This old species was assumed to be the size of a Chihuahua, but continuous evolution determined them to reach a higher step on the mammals’ scale and thus they has become one of the top predators millions of years ago. Scientists claim that bear dogs were attested in the North America which seems to have been an auspicious environment for their evolution.
This species of carnivorous mammals known as amphicyonids got their name from their striking resemblance to our dogs and bears. They seemed to be a mixture, a hybrid between what we now know them to be dogs and bears. Their similarities with these two species are only in body posture and shape. Their features don’t really relate them to neither bears nor dogs.
Susumu Tomiya, who is a vertebrate paleontologist at The Field Museum of Natural History in Chicago claimed that when amphicyonids first appeared approximately 40 million years ago, bears and dogs were not even attested yet. The first member of this species which was discovered only weighed a few kilograms. After millions of years of evolution, this animal reached the size of a fox, than of a coyote, becoming bigger and bigger as the time passed by, leading it to the scale of a bear.
Tomiya discovered an unknown carnivore fossil when he was looking through the collections of The Field Museum. He believed that the fossil pertains to an undetected amphicyonid. He asked for the help of Jack Tzeng, another vertebrate paleontologist from the State University of New York, who analyzed this fossil very carefully. He knew about the discovery of another similar fossil which was unveiled in the same location in Texas, at almost three hundred kilometers away from El Paso.
These fossils were first regarded in 1986 being almost 38 million years old. In its first steps of evolution, this creature was estimated to weigh almost 2.5 kilograms, having a skull which was 8 centimeters long. Tseng and Tomiya had conducted a study in which they have used X-rays which helped them generate 3D scans of the internal characteristics of the fossil. Those scans identified them as amphicyonids.
Isn’t it amazing how a creature of the size of a little dog managed to evolve to the size and strength of a bear? Aren’t you curious to find out more about similar fossil’s discoveries?
Image courtesy of: fossil in florida