Researchers from the University of Arizona have discovered fossilized remains of extinct elephant-like animals called gomphotheres, along with artifacts of the ancient Clovis people.

The discovery suggests Clovis, one of the earliest human settlements in North America, hunted and ate gomphotheres. As a group, Clovis was believed to hunt and eat relatives of the ancient elephant, such as mammoths and mastodons.

Vance Holliday, lead researcher and archaeologist from the University of Arizona, and his colleagues began the excavation in some parts of Mexico and the United States when they found the bones of two gomphotheres in 2007. At the time, the team wasn't sure what kind of animal they had discovered.

"At first, just based on the size of the bone, we thought maybe it was a bison, because the extinct bison were a little bigger than our modern bison," Holliday said in a press release.

Although it was previously-known that humans used to hunt and eat gomphotheres, Holliday's discovery was the first direct evidence that the two species once shared an ecosystem. The skeletal remains of the gomphotheres were 13,400 years old.

Gomphotheres closely resembled mammoths, but they were smaller in size. They were believed to have inhabited the plains of North America, but previous evidence showed that they perished long before humans came to the area. This research proved that when humans arrived in North America, gomphotheres were still present in the area.

As the research team continued their excavation, they also unearthed artifacts belonging to the Clovis group, including spear tips, projectile points, cutting tools, stone tool-making kits and flint flakes.

The Clovis group was famous for their skill in making their own tools. The tribe was named after the site where they were first found in New Mexico during the 1930s.

Further details of this study were published in the July 15 issue of Proceedings of the National Academy of Sciences.