During excavations in the Letti basin in northern Sudan, archaeologists have unearthed 7,000-year-old bone tools used to bleed cows. Explorers believe this may be the earliest evidence of such a practice.

7,000-year-old burials were discovered during the excavation of a cemetery in the Letti Basin, including the remains of an elderly man and animal skin fragments that had been dyed red by the mineral ochre. The burials belonged to some of the region’s first cattle breeders.

Along with five bone blades probably made from cattle bones, the burial pit also contained a small bowl with ochre traces. The bone blades had a funnel-like or gutter-like shape and were still razor-sharp, as revealed by a closer inspection.

The tools immediately drew the attention of researchers, Piotr Osypiński, one of the excavations’ lead archaeologists, told Science in Poland.