Life found a way. Two captive California condors were born from unfertilized eggs, suggesting the critically endangered species is able to reproduce asexually, according to a new study.
The discovery was found by a team of researchers at the San Diego Zoo Wildlife Alliance. When checking the biological samples of two California condor chicks, the examined birds showed they were genetically related to their mother, but had no evidence of having a father.
Oliver Ryder, Kleberg Endowed Director of Conservation Genetics at San Diego Zoo Wildlife Alliance and co-author of the study, said in a statement the team wasn’t looking for proof of asexual reproduction, and the results “just hit us in the face.” Their findings were published in the Journal of Hereditary on Thursday.
“This is truly an amazing discovery,” Ryder said. “We only confirmed it because of the normal genetic studies we do to prove parentage. Our results showed that both eggs possessed the expected male ZZ sex chromosomes, but all markers were only inherited from their (mothers), verifying our findings.”
The condors’ birthing process is known as as parthenogenesis, when an embryo not fertilized by sperm continues to develop with just the mother’s genetic code. Animals such as Komodo dragons and starfish can reproduce through this process, but it is very rare among birds, as turkeys and pigeons are one of few avian animals able to do so.
What makes the condors’ discovery only more puzzling is that the mothers of the chicks were able to mate with a male partner.
The two chicks came from their own mother, but they were each housed with a fertile male counterpart, according to the zoo. One mother had given birth to 11 chicks before, while the other had given birth to 23 chicks in 20 years with the same partner. The zoo said the latter female reproduced with a mate two more times after reproducing asexually.
“We believe that our findings represent the first instance of facultative avian parthenogenesis in a wild bird species, where both a male and a female are housed together,” said Cynthia Steiner, associate director for the conservation research division at San Diego Zoo Wildlife Alliance and co-author of the study.
With a 10-foot wingspan, California condors are the largest flying birds in North America. They once ranged throughout the West Coast, but only 22 survived in the 1980s when the U.S. government captured them and placed them in zoos for captive breeding. About 160 were bred at the San Diego Zoo and Safari Park.
As for how many condors are alive today, the number is not known. The Associated Press reported there are around 500 alive, with 300 of them living in the wild in California, Arizona, Utah and Mexico.
The International Union for Conservation of Nature, which lists the species as critically endangered, says there are only 93 mature individuals in the wild, but the population is increasing.
While the two chicks didn’t live up to the life expectancy of 60 – one born in 2001 died two years later and the other died in 2017 at the age of 8 – scientists are wondering if other species are able to replicate the process, and if it could bring new life to the California condor population.
Contributing: Associated Press
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