Extreme drought unearthed a human skull in the Minnesota River. A forensic anthropologist says it may be 8,000 years old.

A human skull was found by kayakers along the Minnesota River during the last days of summer last year. Experts think it could be a man who lived 8,000 years ago.

According to The Washington Post, two kayakers found a brownish chunk of skull while kayaking on the Minnesota River. They came across the skull in September when the water levels in lakes and rivers were low. The discovery was thought to be the remains of a person who recently died.

The FBI forensic anthropologist was sent the bone fragment to try and find out where it came from. The anthropologist used carbon dating to calculate its age, a technique that hinges on the fact that all living things absorb radioactive carbon from the atmosphere and food sources. Researchers can estimate how long a plant or animal has been dead by looking at the carbon that it has accumulated. The anthropologist estimated that the skull belonged to a young man who lived between 5,500 and 6,000 BC.

Scott Hable, Renville County sheriff, told The Washington Post that they were taken back.

According to CBS Minneapolis affiliate WCCO, the anthropologist found that the man ate a lot of maize, pearl millet, and Sorghum long before farming methods were invented. The depressed area on the skull fragment suggests he may have suffered a traumatic brain injury.

The sheriff's office said in a statement that they are fortunate to have the partners that they do to assist them in the investigation and that they have come across a piece of history.

The announcement and pictures of the skull caused upset in the Native American community. According to Minnesota news organization MPR News, Dylan Goetsch, a cultural resources specialist with the Minnesota Indian Affairs Council, said in a statement that it was unacceptable and offensive for tribes to learn of the skull through Facebook. The social media post from the sheriff's office has been taken down.

More modern human remains have been found at Nevada's Lake Mead, which is the country's largest reservoir. The remains of a person were found in a rusty barrel by lake visitors.

Climate change has been linked to longer and more severe droughts. Warming temperatures are melting ice and snow and revealing bodies that have been buried for decades, according to a forensic anthropologist who consults with the Clark County, Nevada, coroner's office.

Human remains of missing persons are likely to be revealed as the water level continues to fall.

Less than a week after the body in a barrel was reported, more human remains were found near the water.