On April 26th 2017, archaeologists announced that they had found evidence that humans may have lived in North America 130,000 years ago. A study posted in the journal Nature stated that the recovery of mastodon bones discovered in southern California showed signs that humans may have attacked the animal near the time of its demise. The study has sparked a debate about humans living on the continent 115,400 years before humans were believed to be in North America.
The fossils were first discovered near a freeway construction site in San Diego in 1992. The location of the mastodon's remains has been named the Cerutii Mastodon Site, after Richard Cerutii, the paleontologist who made the discovery. The animal bones, tusks, and molars were found buried along with stone tools which included hammers and anvils believed to have been used in either extraction of bone marrow, or raw materials for making such tools.
Thomas Demere, Steven Holen, and a team of researchers from the San Diego Natural History Museum, examined the mastodon remains using a technique called, "uranium-thorium dating. This process allowed them to arrive at a date of 130,000 years. Further study of the bones and teeth revealed that some of the remains had a pattern of breakage called "spiral fracturing." The team says that this occurs when the bones are fresh.
They also say that some of the bones show signs of being smashed with very hard objects. Other researchers, such as John McNabb of the University of South Hampton, say that, "Until we actually find a skeleton at this site, or at a site of a comparable age in the Americas, it's all an open speculation and we just don't know."
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