Sea otters, one of the few animals that use tools to access their food, have been found to benefit from this behavior in a new study. Most of the otters that use tools are female, and this study found that they are able to eat larger prey and reduce tooth damage when their preferred prey becomes scarce. The researchers followed 196 radio-tagged southern sea otters off the coast of California to understand how they use tools in their environment. They monitored the otters’ tool use, dietary patterns, and dental health to better grasp the relationship between these factors.
The study, led by Chris Law from The University of Texas at Austin along with researchers from UC Santa Cruz, Monterey Bay Aquarium, and other institutions, discovered that both male and female otters using tools showed a reduction in tooth injuries. Females, in particular, use tools more frequently to overcome their smaller size and weaker biting ability as they need to meet their calorie demands to raise their pups. This behavior is crucial for their survival, ensuring they can efficiently forage and consume enough food to sustain themselves and their offspring.
In the coastal Central California region, some of the sea otters’ preferred prey, such as large abalone and sea urchins, have become scarce, leading otters to rely more on crabs, clams, mussels, and small marine snails with hard shells that can damage their teeth. Maintaining tooth condition is vital for otters’ survival, as worn or damaged teeth can lead to starvation. Using tools allows individual otters to diversify their diets and access different types of prey, helping them meet their calorie needs. The study found that female otters had less tooth damage compared to males, underscoring the importance of tool use for their survival.
Female otters are more likely to use tools, and those that do can access harder or larger prey compared to otters that do not use tools. Female dolphins, chimps, and bonobos also exhibit similar behavior, with females passing down tool-use skills to their offspring. Southern sea otters are listed as a threatened species under the U.S. Endangered Species Act, with only around 3,000 individuals in California. These otters play a critical role in marine ecosystems by preying on sea urchins that feed on kelp forests, highlighting the importance of understanding their foraging behaviors.
Scientists involved in the study include Rita Mehta, Tim Tinker, Jessica Fujii, Teri Nicholson, Michelle Staedler, Joseph Tomoleoni, and Colleen Young hailing from various institutions. The research was funded by organizations such as the U.S. National Science Foundation, Packard Foundation, Coastal Conservancy, U.S. Fish and Wildlife Service, Pacific Gas & Electric, and Bureau of Ocean Energy Management. This study sheds light on the significance of tool use among sea otters, particularly females, and its role in their survival and foraging behaviors in changing environments, providing valuable insights for the conservation of this threatened species.