On Tuesday, a report describing a Stone Age graveyard in Niger was released. Although the ancient site was discovered back in 2000, according to Paul Sereno, a paleontologist of the University of Chicago, all this time was required for putting together all the information.

The team came across skeletons of humans and animals while engaged in a project focused on dinosaur fossils. Strangely enough, the site contains about two hundred graves that seem to have dug by two distinct civilizations at a time difference of possibly 1,000 years.

The people from one of the groups were called Kiffians; according to the research team, they were tall, strong hunter-gatherers who, about 8,000 years ago, had to leave the area because of a terrible drought that affected the local water supply.

The other group contained people called Tenerians; they were smaller than the Kiffians and settled down in the region between 7,000 and 4,500 years ago. There were a lot of artifacts found from both cultures, including fish hooks, jewelry and ceramics.

Chris Stojanowski, a bioarchaeologist from Arizona State University who was involved in the study, said it was quite strange to see two such biologically distinct groups using the same site to bury their dead. 

As a conclusion of the report, the team said that, by combining the newly found data with the information gathered in other sites located in North Africa, "the complex history of biosocial evolution in the face of severe climate fluctuation in the Sahara" is just beginning to be understood and that a lot more is to come.