Sheep with deformed horns are among the more mysterious animal remains discovered at an ancient Egyptian burial site dating back to around 3700 BC. They also represent the oldest physical evidence of humans modifying the horns of livestock.

“The sheep were deliberately made ‘special’ by castration,” says Wim Van Neer at the Royal Belgian Institute of Natural Sciences. “In addition, their horns were directed upward, and in one case, the horns were removed.”