Crocodile in Costa Rican Zoo Impregnated Itself, a First Ever Recorded
Rebecca West
The first known case of a crocodile that became pregnant without ever having mated has been identified at a Costa Rican zoo. How do we know that? The semiaquatic reptile produced a foetus that was 99.9 percent genetically identical to itself!
The phenomenon is often referred to as a "virgin birth" and has been reported in various species of fish, birds, and reptiles. It has not, however, been seen in crocodiles before — but was anybody checking? Apparently not, but we'll get to that in a minute.
The egg was laid back in January 2018 by an 18-year-old American crocodile at Dominical Reptile Park, known locally as Parque Reptilandia. The foetus inside the egg was said to be fully formed but ended up being stillborn, so it never actually hatched.
Virgin Births
The virgin mother-to-be was 2 years old when she was first captured and kept separated from other crocodiles for her entire life. Due to this, the park's scientists reached out to Dr. Warren Booth, a scientist working at Virginia Tech here in the U.S. Booth has reportedly been studying parthenogenesis, aka virgin births, for at least 11 years now.
After analyzing the foetus, Booth found it to be more than 99.9 percent genetically identical to its mother, which means that it had no father.
He admitted to BBC News that he wasn't surprised by the discovery.
Parthenogenesis in Animals
"We see it in sharks, birds, snakes, and lizards, and it is remarkably common and widespread."
He raised the theory that one possible reason parthenogenesis hasn't been reported in crocodiles yet is that people haven't been looking for the occurrence.
"There was a big increase in reports of parthenogenesis when people started keeping pet snakes. But your average reptile keeper doesn't keep a crocodile," he explained.
One thought is that the phenomena occurs in species capable of parthenogenesis when their numbers decline, and are possibly on the cusp of extinction. Booth added that this may have happened to certain species of dinosaurs when their numbers fell due to changes in the environment.
American Crocodiles
The research has been published in the Royal Society journal, Biology Letters.
American crocodiles are a species of crocodilian found in the Neotropics. The creatures are the most widespread of the four extant species of crocodiles from the Americas, with populations seen from South Florida and the coasts of Mexico, to as far south as Peru and Venezuela.
Males can grow up to 20 feet in length, and the average clutch of eggs is 30 to 70! They can get pretty old, too. For instance, American crocodiles have a lifespan of around 70 years, while saltwater crocodiles can live up to 100 years.
The conservation status of the American crocodile is currently listed as vulnerable but their populations are said to be increasing.
