An otter that lived 6 million years ago may have been a prime predator during its time. The creature's jaws suggest a strong bite that could crush harder and larger prey.
Wolf-Sized Prehistoric Otter
Modern otters possess characteristics that charm many people, but as it turns out, some of their ancestors are quite formidable ancient predators. A team of researchers found that an extinct species of otter that lived about 6 million years ago was wolf-sized at 50 kg in weight, making it larger than all currently living otter species.
Apart from being large in size, researchers also found that the Siamogale melilutra's jaws have a biting ability that suggests it might have been a prime predator compared to its living relatives. With such strong jaws, they might have preyed on hard mollusks, birds, and small mammals. However, their actual diet remains unknown.
A Formidable Hunter With Strong Jaws
In order to understand the S. melilutra better, researchers created 3D computerized models of the ancient otter as well as 10 of the 13 living otter species and compared how the jaw bones bend with biting force. They created the S. melilutra's jaw bone model out of the digital reconstruction of the ancient creature's crushed fossils.
Researchers found a linear relationship between animal size and jaw stiffness whereby smaller otters had stiffer, sturdier jaws. However, the S. melilutra possessed jaws that were evidently six times sturdier than researchers expected given its size. With such strong jaws and large size, the ancient otter might have been an excellent hunter.
Interestingly, the location where the ancient otter's remains were found once had a shallow swamp or lake, and surrounded by a dense forest. As such, there was likely a large diversity of creatures in the environment the S. melilutra lived in which includes turtles, mollusks, water birds, crabs, and fish.
"In the shallow swamp of South China, it's possible that an abundance of big clams drove these giant otters to acquire their rare traits, including their crushing teeth and robust jaws," said Xiaoming Wang of the Chinese Academy of Sciences, American Museum of Natural History, and Natural History Museum of Los Angeles County, co-author of the research.
Modern-day otters have evolved to living and hunting in marine environments, and have diets that are diverse among the 13 species scattered in the Americas, Asia, Europe, and Africa. Their body weights range from 4 kg up to 45 kg, and are known for using tools in crushing harder foods.
Researchers surmise that perhaps the ancient otters developed the sturdy jaws because they did not have a tool-use capability, although this could just be one factor and cannot possibly explain the trend in species development. As such, further studies need to be done to understand the species.
The study is published in Scientific Reports.