When workers started reconstruction of Oregon State University's Reser Stadium, they had no idea that they are going to unearth an ancient treasure: massive femur and prehistoric mammoth bones.

The discovery of over a thousand ancient bones, ranging from bison to mammoth, on Monday suggested that the site was home to animals more than 10,000 years ago. As per a press release by the university, the construction workers excavated the ancient remains in the north end zone of the stadium when they were renovating the site.

The renovation was stopped immediately after the discovery of femurs, said Tim Sissel, senior project manager for Fortis Construction Inc. According to Sissel, the university’s anthropology professor and archaeologist Loren Davis was called to the discovery site to examine the remains.

Davis collected the bones, examined them and found that they were about 10,000 years old. “Animals who were sick would often go to a body of water and die there, so it’s not unusual to find a group of bones like this. We had all of these types of animals in the Willamette Valley back then”, Davis explained.

Apart from mammoth bones, construction crews unearthed some bones that belong to a bison and camel. The largest bone excavated was a mammoth femur. It was approximately 5 feet long. About the femur, Davis said that it suggests it belongs to a mammoth that was over 14 to 15 feet.

Davis also said that no human bone has been unearthed and there are no signs that the animals were hunted by humans. According to him, the remains could be used to provide a great learning experience to students and other enthusiasts. They can learn how to identify extinct animal bones, he added.