Crocodile impregnated itself in first recorded "virgin birth"

In Costa Rica, a female crocodile birthed a clutch of eggs. No big deal except for the fact that this particular crocodile hadn't been around any male crocodiles in more than 15 years. Of all the eggs, only one of them developed into a foetus—and it didn't survive—but it was 99.9% genetically identical to its mother. It's the first evidence that crocodiles are capable of parthenogenesis, or "virgin births." Yep, like with the dinosaurs in Jurassic Park, life, uh, found a way.

From the New York Times:

While parthenogenesis has been identified in creatures as diverse as king cobras, sawfish and California condors, this is the first time it has been found in crocodiles[…]

Here's how a virgin birth happens: As an egg cell matures in its mother's body, it divides repeatedly to generate a final product with exactly half the genes needed for an individual. Three smaller cellular sacs containing chromosomes, known as polar bodies, are formed as byproducts. Polar bodies usually wither away. But in vertebrates that can perform parthenogenesis, one polar body sometimes fuses with the egg, creating a cell with the necessary complement of chromosomes to form an individual[…]

This is precisely what happens in parthenogenesis in birds, lizards and snakes, Dr. Booth said, suggesting that this group of animals inherited the ability from a common ancestor. But crocodiles evolved long before many other modern parthenogenetic animals, which suggests intriguing possibilities about the creatures that came in between.

"What this tells us is it's very likely that this also happened in pterosaurs and dinosaurs," Dr. Booth said.