Natures wonders: sea otters use tools for food gathering (Introduction)

by David Turell , Thursday, May 16, 2024, 20:54 (123 days ago) @ David Turell

Seen mainly in females:

https://phys.org/news/2024-05-sea-otter-tool-access-larger.html

"Sea otters are one of the few animals that use tools to access their food, and a new study has found that individual sea otters that use tools—most of whom are female—are able to eat larger prey and reduce tooth damage when their preferred prey becomes depleted.

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"The research team from The University of Texas at Austin, University of California, Santa Cruz, Monterey Bay Aquarium and elsewhere monitored how the marine mammals used tools—such as rocks, shells and trash—to break open prey and identified links to the animals' dietary patterns and dental health.

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"'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 southern sea otter's range of coastal Central California, some of the preferred prey such as large abalone and sea urchins, are not difficult to break open. However, these food resources dwindle or disappear in many areas. This leads otters to prey more often on crabs, clams, mussels and small marine snails whose hard shells can damage the otter's teeth in the process of prying them open.

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"Research shows that female otters are more likely to use tools, and in the study, those that did were able to access harder or larger prey than otters that did not use tools. In fact, females were able to consume prey that were up to 35% harder compared with male tool users and non–tool users.

"Female dolphins, chimps and bonobos are also known to use tools more than their male counterparts, probably for the same reasons. In these species, females tend to raise offspring, and they are often the ones that pass down tool-use behavior to offspring.

"Listed as a threatened species under the U.S. Endangered Species Act, southern sea otters number only about 3,000 in California, where they play a critical role in marine ecosystems preying on sea urchins that feed on kelp forests." (my bold)

Comment: the last paragraph is a delightful account of how otters fit into an ecosystem. The same issue arises, a learned instinct or designed instinct? I think learned.