Ancient Egyptians shaved off their eyebrows to mourn the death of their cats.

Ancient Egyptians believed cats were "magical creatures", capable of bringing good luck to the people who housed them. To honour the cats, families often dressed them in jewels and fed them treats fit for royalty. When the cats died, they were mummified and as a sign of mourning, the cat owners shaved off their eyebrows, continuing to mourn until their eyebrows grew back.