Virgin Snake Gives Birth Two Years in a Row

A yellow-bellied water snake. A member of this species at Missouri's Cape Girardeau Conservation Nature has given birth two years in a row without sexual contact. Missouri Department of Conservation

A snake in Missouri that hasn't had contact with a male snake in at least eight years gave birth this summer to offspring for the second year in a row. It's a rare example of a phenomenon called parthenogenesis, wherein certain animals, usually insects, can reproduce without sexual contact. It has been demonstrated in 10 different snake species, although it is quite uncommon, Quartz notes.

Officials at the Missouri Department of Conservation's Cape Girardeau Conservation Nature Center told the Associated Press that the baby snakes born this year didn't survive, but the offspring born last year are alive and well, and on display at the center. Animals produced via parthenogenesis often are not fertile.

Parthenogenesis can also occur in amphibians, fish and reptiles, and rarely in birds, but not mammals. Parthenogenesis occurs when two unfertilized eggs combine to produce a viable offspring. "It is often called a form of 'asexual reproduction,' but it is more accurately defined as an incomplete form of sexual reproduction," the University of Wisconsin explains. "This is because it involves the production, activation, and development of a female egg which is a specialized reproductive cell."

It has been almost exclusively studied in captive animals, although a recent study found evidence of "virgin births" in endangered sawfish in the wild.