LOOK: Caiman Discovered With Bizarre Tail ‘Mutation’

by Caitlin Berard
(Photo by Wolfgang Kaehler/LightRocket via Getty Images)

The cousins of alligators, caimans are similar in appearance but have bony plays buried in the skin on their bellies. They’re also smaller than the American alligator, reaching only 5 to 10 feet in length, depending on the specific type.

Like its relatives, caimans spend their days basking in the sun and using their powerful tails to propel them through the water while their legs remain relaxed at their sides.

All crocodilians share the same long and tapered tail shape, which they use to swim by sweeping it back and forth in the water. It’s the most crucial part of their anatomy, as it serves as their main means of transportation, hunting, and protection.

With that in mind, this little caiman might have a tougher time in the wild than his relatives. Rather than a tapered tail, the caiman’s lower half more closely resembles a mermaid than a crocodilian.

It may be possible for the caiman to swim using natural sweeping movements. However, it won’t be nearly as effective.

So, what caused such a deformity? It’s easy to assume its unusual tail is the result of a genetic mutation, but it’s more likely that the caiman suffered an injury shortly after birth and its tail healed incorrectly. Rather than regrowing a single tail tip, the injury sprouted two tips, which then fused into the fin-like structure.

Whales and dolphins have similar tail shapes to the deformed caiman but use up/down locomotion to swim. While crocodilians can move their tails up and down, it’s a far weaker and more limited movement than their typical side-to-side method.

‘Mutant’ Caiman Resembles Ancient Crocodilians

Interestingly, though the whale-tailed caiman is likely the result of an injury and not de-evolution, it does resemble an ancient member of the family. Crocodilians swam in the same waters as the dinosaurs, appearing 95 million years ago in the Late Cretaceous period. They aren’t technically dinosaurs but do belong to the same reptile group, Archosauria.

Just a few years ago, scientists added another piece to the ever-growing puzzle that is the evolutionary history of crocodilians like caimans and crocodiles.

The fossil was found in Hungary’s Gerecse Mountains and analyzed by an international team of researchers. Though every fossil find is an interesting one, this one was especially intriguing, as the animal had both heavy, bony armor and dolphin-like tail fins and flippers – just like the mutant caiman.

“This fossil provides a unique insight into how crocodiles began evolving into dolphin and killer whale-like forms more than 180 million years ago,” study author Mark Young said in a news release. “The presence of both bony armor and a tail fin highlights the remarkable diversity of Jurassic-era crocodiles.”