After 30 Years of Breeding Condors, a Secret Comes Out
When you get to be as endangered as the California condor, your sex life becomes a highly public affair. Since 1983, when the number of California condors in existence was a mere 22, biologists have been carefully breeding the birds in captivity. They kept track of who mated with whom, how many offspring they had, and when those offspring were released into the wild. All of this is logged in the official California-condor “studbook.”
So it was quite a shock when, a few years ago, scientists conducting DNA tests as part of routine research found two condors with unexpected paternity. These two birds—known by their studbook numbers as SB260 and SB517—were not related to the fathers recorded in the studbook. Actually, they had no fathers at all. A full 100 percent of their DNA had come from their respective mothers. “We were confronted with this inexplicable data set,” says Oliver Ryder, a conservation geneticist at the San Diego Zoo Wildlife Alliance.
The only possible explanation was a strange one: The eggs that produced these two condors must have essentially fertilized themselves without any sperm. The phenomenon is known as parthenogenesis or, colloquially, “virgin birth.” (The two mothers in this case weren’t technically virgins; they had previously produced normal chicks with the male they were housed with. As I said, not much sexual privacy when you’re a California condor.) Parthenogenesis has been studied in other birds, like turkeys and chickens. It’s also been documented in snakes, lizards, sharks, rays, and bony fish—both in captivity and more recently in the wild. Many of these discoveries were accidental, and all of these accidents have scientists wondering if parthenogenesis is not as rare as once thought.
https://www.theatlantic.com/science/archive/2021/10/california-condors-are-capable-virgin-birth/620517/
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