According to a new study, the ancient relative of modern-day otters may have been a dominant predator. The wolf-sized otter, which lived roughly 6 million years ago, weighed in at roughly 110 lb (50 kg) and had a surprisingly powerful bite.

Present-day otters are among the most beloved members of the animal kingdom. According to a new study carried out by an international team of scientists, however, the otters we know and love today had a far more formidable ancestor – a large mammal known as Siamogale melilutra.

In an attempt to better understand the power of the ancient otter, the scientists created a computer model to simulate the strain that biting down put on the animal's jaw.

The models used in the study were created from computed tomography scans of skull, and, in the case of Siamogale melilutra, fossil fragments. One of the most painstaking elements involved in the creation of the prehistoric otter model was the reconstruction of its cranium from scans of crushed fossil remains.

The scientists compared this data with models displaying how the jaw bones of 10 current-day otter species flexed under the strain of biting.

Initially, the authors of the study had expected that the prehistoric otter jaw would have similar characteristics to the jaws of modern day species, but capable of creating more force due to the extinct animal's larger size. The results of the study revealed a distinguishing characteristic of the Siamogale melilutra's jaw that set it apart from its modern day relatives, and granted it a surprisingly powerful bite.

The computer simulations of the current-day otter species displayed a clear relationship between the size of the otter and the stiffness of their jaws. Smaller otters were found to have stiffer jaws, while the larger species were more flexible.

Siamogale melilutra bucked this trend, with computer simulations showing that the larger ancient otter had a jaw roughly six times sturdier than would be expected based on its modern counterparts. The surprisingly powerful bite would have allowed the animal to crush large mollusks, birds, and small mammals.

The team believes that the creature's size combined with its above-average jaw strength could have made Siamogale melilutra a dominant predator in the region of southwest China where it lived some 6 million years ago.

"At the time that the otter lived, the area where its remains were found included a swamp or a shallow lake surrounded by evergreen forest or dense woodland," comments Dr. Denise F. Su, a paleoecologist at the Cleveland Museum of Natural History who was among the team that first discovered the giant otter fossil. "There was a diverse aquatic fauna at Shuitangba, including fish, crab, mollusks, turtles and frogs, as well as many different species of water birds, all of which could have been potential prey for S. melilutra."

The study has been published in the journal Scientific Reports.

Source: University at Buffalo

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