Otters have lived on Earth for around 23 million years, although scientists believe that a significant change occurred around 7 million years ago that shifted them away from their ancestors and closer to the otter species that we have today. They probably moved into the water to escape from predators or to find better sources of food. Neither scenario is hard to imagine. All otters except for the sea otter can move easily on land and in water and need to move between the two: the water to fish and the land to sleep in their dens. Most of the fossils which have been found show evidence of animals who lived on land. The reason for this assumption is because primarily water animals’ remains would be at the bottom on rivers, lakes, or the ocean and so would have less of a chance of being found, especially if there is still water in that location, and might not have been fossilized due to water washing away sediments. This means that there is a lot of mystery as to exactly when otters entered the water, and to what extent they lived their lives aquatically. Further, the research into their evolution has progressed very slowly because of the need to focus efforts on the protection and conservation of otters today, which is a more pressing mission.
Originally, this blog post was going be about a generalized overview of otter evolution, talking about who their ancestors were and why their current adaptations were useful and necessary. That was until I started searching for “prehistoric otters”. Google brought up one topic over and over again which surprised me and might surprise you also.
That topic is the giant wolf-sized otter in China.
These huge otters lived in what is now China about 6 million years ago. Lead scientist Jack Tseng has said that they were probably top predators in their area, and with a weight of over 100 pounds (most otters today don’t reach over 20 pounds) and a crushing bite, it isn’t hard to see why. This bite of Siamogale melilutra is an interesting area in which this animal stands out, aside from being a gigantic otter. The jaw in the fossil remains indicate that the jaw was stiff, a common trait in smaller otters, and which results in a stronger bite relative to body size. Tseng and his team used computer simulations and scans to determine the strength of the bite, using modern otters as a reference, and found that the strength was six times what they would have expected. Only one other animal that we know of has been large and had such a stiff jaw, Kolponomos newportensis, a bear living 20 million years ago. Scientists know that hard-shelled mollusks were abundant around the time that S. melilutra was around, and so they think that these made up a large part of their diet. Perhaps this stiff jaw and strong bite helped them break through the shells of their prey.
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Have you heard of the giant otters before? Do you have any knowledge to add to the conversation or any questions? Let me know in the comments below. We publish a new blog every Tuesday and Friday; thank you for reading and, until next time, goodbye!
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