by Something strangely rare has happened in a zoo in Costa Rica: a female crocodile of the species Crocodylus acutus generated its own offspring without the involvement of any males. Known as facultative parthenogenesis or “virgin birth”, the condition has never been recorded in crocodiles.
Even more curious in the case of the “virgin” and independent female crocodile, the fetus produced was 99.9% genetically identical to her, according to a study published in the journal Biology Letters.
Story of the “virgin” crocodile who fertilized an egg by itself
The study that proved the very rare case of parthenogenesis in crocodiles was conducted by researchers from Parque Reptilandia, Costa Rica, and Virginia Polytechnic Institute and State University (Virginia Tech), in the USA.
As the authors describe, the egg was generated by a female of the American crocodile species in 2018. She had lived in isolation from other animals, including members of her species, since the age of two, for reasons that have not been clarified.
Despite the feat of generating an egg 100% autonomously, without the help of a male, the newborn did not survive. Even though it formed, the fetus died before hatching, configuring a case of stillbirth. Here’s what the “virgin” mother and stillborn calf looked like:
In this case from Costa Rica, the scientists explain that “the failure of this parthenogenesis to hatch should not be taken as an indicator that any [ovos] crocodile parthenogens will be unrealizable”. Finally, an extraordinary calf in its gestation can inhabit this world.
Species can reproduce without a male
Stories like this grab attention because they’re impossible for humans, but in nature other species practice facultative parthenogenesis, as Warren Booth, one of the study’s authors, explains. researcher at Viginia Tech. ”We see this in sharks [como um episódio recente na Itália], birds, snakes and lizards. It’s something remarkably common and widespread,” he told the BBC.
Booth even explains that the phenomenon in crocodiles can be much more recurrent than you think. The problem is that it is not documented and, even less, studied properly, as happened in the zoo in Costa Rica.
At this point, the expert sheds light on a recent snake-related situation. “There was a huge increase in reports of parthenogenesis when people started having pet snakes,” he says. The explanation for the increase was quite simple: more people were watching these animals, increasing the stats.
Among the hypotheses associated with the ability to reproduce asexually, it is possible that it was inherited from the dinosaurs, when their populations were in decline and it was really difficult to find partners. “The fact that the mechanism of parthenogenesis is the same in so many different species suggests that this is a very ancient trait that was inherited over time. So this reinforces the idea that dinosaurs were also capable of reproducing in this way,” Booth suggests. .
Parthenogenesis in nature
“While it is disappointing that the crocodile parthenogenesis produced did not hatch, it is not uncommon to see non-viable fetuses and developmental abnormalities within litters,” the study authors state, who were born apparently healthy.
In an experiment on parthenogenesis in turkeys, researchers followed a farm for nine years and found that only 3.3% of parthenogenetic eggs hatched. During this entire period, more than 2,000 eggs of the type were identified, but only 68 produced live offspring. Although the survival of these animals is even rarer, if they survive to adulthood, they are able to reproduce.
Source: Biology Letters and BBC
