Virgin birth in crocodile reported in Costa Rica zoo

In an unusual occurrence, the first case of virgin birth was reported from a zoo in Costa Rica, in which a female crocodile gave birth to a foetus 99.9% genetically identical to herself.

According to BBC, this phenomenon was also found in species of birds, fish and other reptiles, but never before in crocodiles.

Scientists noted that the trait might be inherited from an evolutionary ancestor, so dinosaurs might also have been capable of self-reproduction.

In 2018, an 18-year-old American crocodile laid an egg in Parque Reptilania. Despite being fully formed, but stillborn, it did not hatch.

The female was obtained at the age of two and was not kept with other crocodiles for her entire life.

After encountering the situation of virgin birth, the park's scientific team contacted a US team from Virginia Polytechnic, which specialises in virgin births, known as parthenogenesis.

After analysis, they also confirmed that there was no father of the newborn.

The researchers wrote in the Royal Society journal Biology Letters, that virgin births may be more common in crocodiles, and have gone unnoticed until now because people have not been looking for instances of them.

"It is not uncommon for captive reptiles to lay clutches of eggs, given the period of isolation from mates, these would normally be considered non-viable and discarded. These findings, therefore, suggest that eggs should be assessed for potential viability when males are absent," the scientists said.

"Furthermore, given that [virgin births] can occur in the presence of potential mates, instances of this may be missed when reproduction occurs in females co-habited with males."

It is not clear why this occurs in different species, but these are cropping up in the scientific literature more often, probably because researchers are now searching for it.

According to one theory, it happens in species capable of parthenogenesis when numbers dwindle, and they are on the verge of extinction.

"This new evidence offers tantalizing insights into the possible reproductive capabilities of extinct relatives of crocodiles, notably the dinosaurs," write experts.