The crocodile that reproduced on its own

The unusual event occurred in a reptile park in Costa Rica. A female laid an egg containing a fetus 99.9% genetically identical to her. This is the crocodile that reproduced unaided. The so-called “virgin birth” phenomenon has occurred before in other species. But never before in crocodiles.

This trait could be inherited from an evolutionary ancestor. Because of this, perhaps dinosaurs might also have been able to self-reproduce. The egg was laid by an 18-year-old female American crocodile in Reptilandia Park.

The crocodile that reproduced unaided is the first recorded case in these reptiles.
The crocodile that reproduced unaided is the first recorded case in these reptiles.

More and more cases

The fetus inside was fully formed but dead, so it did not hatch. The female arrived at the zoo when she was two years old and was kept apart from other crocodiles throughout her life. The park’s scientific team contacted scientists from the Virginia Polytechnic Institute. They specialize in virgin births, known as parthenogenesis.

The researchers discovered that the fetus was more than 99.9% genetically identical to its mother. This confirms that it had no father. It is not ruled out that this is not so unusual in crocodiles. It could have gone unnoticed, because they have not been looking for instances of them. This is what the authors of the study published in the journal Biology Letters of the Royal Society point out.

“It is not uncommon for captive reptiles to lay clutches of eggs. Given the isolation period of the pairs, the eggs would normally be considered nonviable and discarded. We should assess the potential viability of eggs when males are absent,” the researchers add.

“This can occur in the presence of potential mates. Cases may go unnoticed if they occur in females cohabiting with males.” It is unclear why parthenogenesis occurs in different species. Cases of this phenomenon are occurring more frequently in the scientific literature. And it is probably because scientists are now looking for them.

There are various theories explaining parthenogenesis.
There are different theories explaining parthenogenesis.


There is a theory as to why virgin births occur in species capable of parthenogenesis. It says that it happens when the number of individuals decreases and the species is on the verge of extinction. The crocodile that reproduced unaided gives us new insights into the possibilities for these reptiles. “And also about the crocodiles’ extinct relatives. Especially the dinosaurs,” the scientists point out.

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