In a scientific breakthrough, researchers have recorded the first known instance of a crocodile’s virgin birth. The female American crocodile lived in isolation for 16 years at a zoo in Costa Rica.
What’s the story behind the crocodile’s virgin birth?
This incredible discovery has revealed a surprising reproductive capability in crocodiles and could provide insight into their prehistoric relatives.
In 2018, the female American crocodile, despite her solitary existence, laid 14 eggs in her enclosure, which is not an uncommon occurrence among captive reptiles. However, things took an unexpected turn when, after three months of incubation, scientists discovered a fully formed, stillborn baby crocodile in one of the eggs.
Genetic analysis of the fetus revealed that this was a result of facultative parthenogenesis (FP), a type of reproduction that occurs without the genetic contribution of males. Essentially, the mother’s egg cell developed into a baby without being fertilized by a male’s sperm cell.
Facultative parthenogenesis explained
In FP, the process of egg cell formation divides a precursor cell into four cells. One of these becomes the egg cell, retaining key cellular structures and the gel-like cytoplasm, while the others contain extra genetic material. Interestingly, one of these cells acts like a sperm cell, fusing with the egg to facilitate fertilization.
While this type of reproduction, colloquially known as a “virgin birth,” has been documented in various species of fish, birds, lizards, and snakes, this is the first-known instance in a crocodile.
The American crocodile is a vulnerable species at risk of extinction. According to one hypothesis, FP may be more prevalent among species on the brink of extinction. The discovery of this unusual reproductive strategy could have significant implications for the conservation of endangered crocodile populations.
A glimpse into the prehistoric past
This astounding discovery in Costa Rica could also open new windows into the ancient past. As the study suggests, the “virgin birth” phenomenon might offer insights into the possible reproductive capabilities of extinct archosaurian relatives of crocodilians and birds, specifically members of Pterosauria and Dinosauria that roamed the earth during the Triassic Period about 250 million years ago.