Scientists have found evidence that sea otters may have been using tools for thousands, or even millions, of years.
Tool use in animals is often a sign of sophisticated cognition. Therefore, not only are otters adorable, they are also more cognitively advanced than one might think. Otters were the only known sea mammal to use tools, until it was discovered that dolphins used tools as well. However, scientists postulate that tool use in dolphins only developed about 200 years ago.
Animals with the ability to use tools do so to gain access to food. Otters, in particular, use rocks to break clam, mussel, and snail shells apart. They also use stones as a hammer to break abalone shells off of sea rocks.
Fascinatingly, otters even have a favorite rock. They have a pouch of loose skin under each foreleg in which they store food and the particular rock they use most often. They can also use two rocks as a hammer and anvil, or pound two shelled prey together to break them apart.
Other than rocks, sea otters also use kelp for various purposes. When otters catch crab, they use kelp strands to immobilize their prey. They also wrap themselves in kelp to avoid drifting away as they rest or sleep on the water's surface.
Many other animals, both on land and at sea, use tools. A new study suggests that otters have been at it for a much longer time.
Researchers have found that tool-using Indo-Pacific bottlenose dolphins living within the same area are closely genetically related to each other. This means that the dolphins may have inherited their ability to use tools from their mothers. Knowing this, the researchers wanted to know if this was also the case for sea otters.
They thus tracked diet and tool use patterns in otters living off the coast of California. They also studied the DNA of 197 individual otters in the area.
In the course of the study, the researchers found that otters may have an innate ability to use tools. The researchers found that tool-using otters do not belong to the same family group, unlike the group of bottlenose dolphins. This suggests that tool use may have originated from the otters' distant ancestors.
Young sea otter pups also display an innate ability to use tools even without training or experience. Pups have demonstrated a rudimentary ability to use rocks as tools, even before weaning and before the necessity of using tools to gain access to food.
Researchers aim to to further their study by analyzing sea otter fossils. This analysis may give researchers an idea of when exactly sea otters began using tools. These present findings, however, suggest that otters may have been using tools for thousands to millions of years. Though the researchers are uncertain of when the behavior began to develop, they're certain that otters have been using tools for a long time.
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