According to a recent study, a female crocodile that was discovered with a clutch of eggs in 2018 despite being kept in isolation for 16 is the first recorded case of a crocodile “virgin birth,” Live Science reported.
The female crocodile was taken into captivity 21 years ago at the age of 2 and was placed in an enclosure at Costa Rica’s Parque Reptilandia where she remained isolated for sixteen years. But in January 2018, a clutch of 14 eggs was found within the crocodile’s enclosure.
This type of “virgin birth” is known as facultative parthenogenesis. It is a kind of asexual reproduction that occurs in species that typically reproduce sexually.
Scientists have documented facultative parthenogenesis in various species in captivity, including sharks, snakes, lizards, and birds. But until now, there has never been a recorded case of facultative parthenogenesis among the species Crocodilia, which includes alligators, caimans, crocodiles, and gharials.
In a study published in the journal Biology Letters on Wednesday, researchers said seven of the 14 eggs produced by the isolated crocodile were viable.
Caretakers at the zoo incubated the seven viable eggs, but none of them hatched. Three months later, the caretakers opened the eggs. While the contents of six eggs were undiscernible, one of the eggs contained a fully-formed, non-viable fetus.
DNA testing on the fetus showed that it was nearly identical to the female crocodile.
According to lead researcher Warren Booth, an entomologist from Virginia Tech, while it is disappointing that the egg failed to hatch, it is not unusual for offspring born through facultative parthenogenesis to fail to thrive due to abnormalities.
The researchers suggest that facultative parthenogenesis may be more common among species that are on the brink of extinction and studies conducted on species in the wild rather than captivity could reveal more cases.
According to the study, the discovery of facultative parthenogenesis in a crocodile means that it occurs in both Crocodilia and birds, which descend from dinosaurs, suggesting that there could be a common evolutionary origin for both.