HENDERSONVILLE, N.C. (AP) — A stingray that got pregnant at a North Carolina aquarium this winter despite not having shared a tank with a male of her species for many years has died.

The Aquarium and Shark Lab in Hendersonville said on Facebook late Sunday that the stingray, Charlotte, died after getting a rare reproductive disease. It didn’t go into further detail.

The aquarium, which is in the Blue Ridge Mountains, announced in February that Charlotte had gotten pregnant despite not having shared a tank with a male stingray in at least eight years. But it said in late May that she was suffering from a rare reproductive disease and announced in early June that she hadn’t given birth and was no longer pregnant.

The pregnancy was thought to be the result of a type of asexual reproduction called parthenogenesis, in which offspring develop from unfertilized eggs, meaning there is no genetic contribution by a male. The mostly rare phenomenon can occur in some insects, fish, amphibians, birds and reptiles, but not in mammals. Documented examples have included California condors, Komodo dragons and yellow-bellied water snakes.