Female Otters Adapt to a Changing Environment by Using Tools

Sea otters, known for their adorable appearance and playful behavior, are also one of the few animals that use tools to access their food. A new study has found that individual sea otters, most of whom are female, are able to eat larger prey and reduce tooth damage when their preferred prey becomes scarce.

Researchers from The University of Texas at Austin, University of California, Santa Cruz, Monterey Bay Aquarium, and other institutions followed 196 radio-tagged southern sea otters off the coast of California to study their tool usage. The study, published in Science, revealed that the use of tools among male and female otters led to a reduction in tooth injuries.

Lead researcher Chris Law explained, “The females are likely using tools to overcome their smaller body size and weaker biting ability in order to meet their calorie demands. Raising pups takes a lot of energy, and the females need to be efficient in their foraging. The study shows that tool use is an important behavior for survival.”

In the coastal waters of Central California, sea otters rely on prey such as abalone and sea urchins, which are not difficult to break open. However, as these food sources diminish, otters turn to harder-shelled prey like crabs and clams, which can damage their teeth. Using tools helped female otters access harder or larger prey, reducing tooth damage and ensuring their survival.

The study also found that female otters were more likely to use tools compared to males, similar to other species like dolphins, chimps, and bonobos. With only about 3,000 southern sea otters left in California, understanding their tool usage and dietary patterns is crucial for their conservation. The research was funded by various organizations including the U.S. National Science Foundation and the Packard Foundation.