2023-06-07 14:00:34
Photo credit, JOE WASILEWSKI
“Virgin births” in crocodiles may be common, researchers say.
- Author, By Pallab Ghosh
- Role, science correspondent
The first case of a crocodile becoming pregnant itself has been identified in a zoo in Costa Rica.
She gave birth to a fetus that was 99.9% genetically identical to her.
This “virgin birth” phenomenon has been observed in species of birds, fish and other reptiles, but never in crocodiles.
According to the scientists, this characteristic might be inherited from an evolutionary ancestor, so the dinosaurs might have been able to reproduce themselves.
The egg was laid by an 18-year-old female American crocodile in Parque Reptilania in January 2018. The fetus it contained was fully formed, but was stillborn and therefore did not hatch.
The crocodile that laid the egg was obtained when it was two years old and kept away from other crocodiles for its entire life. For this reason, the park’s science team contacted an American team from Virginia Polytechnic, which specializes in virgin births, known scientifically as parthenogenesis.
This team analyzed the fetus and found that it was more than 99.9% genetically identical to its mother, thus confirming that it had no father.
In a paper published in the Royal Society’s journal Biology Letters, researchers say virgin births may be more common in crocodiles and have so far gone unnoticed because people haven’t looked to find examples.
“It is not uncommon for reptiles in captivity to lay clusters of eggs. Given the period of isolation from conspecifics, these eggs would normally be considered non-viable and discarded. These results therefore suggest that the potential viability of the eggs should be assessed in the absence of males,” the scientists explain in their research report.
“Furthermore, since ‘virgin births’ can occur in the presence of potential mates, instances of this type may be missed when breeding occurs in females cohabiting with males.”
The reasons why parthenogenesis occurs in different species are unclear, but the occurrences appear more often in the scientific literature, probably because researchers are now looking for them. One theory is that it occurs in species capable of parthenogenesis when their numbers are dwindling and they are on the verge of extinction.
“This new evidence offers tantalizing insights into the possible reproductive abilities of extinct crocodile-like species, including dinosaurs,” the scientists write.
1686150858
#Parthenogenesis #crocodile #pregnant
