QuickCheck: Do sea otters have pockets for storing rocks?

Sea Otter (Enhydra lutris) preening itself in Morro Bay, California. - Photo courtesy of Mike Baird (bairdphotos.com) - (CC BY 2.0)

IF YOU are a fan of sea otters, you may have observed – either in real life or in a nature documentary – how these adorable, furry critters are masters at using tools.

Otters are known to use rocks to crack open the shells of their favourite prey, usually invertebrates such as crabs, clams and snails.

But where does one find a rock in the middle of the ocean? Does the otter dive down to the seafloor to hunt for a suitable stone whenever it wants to have a meal?

As it turns out, nature has a solution for everything; it is said that otters have biological 'pockets' under their fur for storing rocks and food. Is this true?

Verdict:

TRUE

Even otters have prized possessions.

Under each of the sea otter's forearms are folds of baggy skin, which act as built-in pouches for tools such as rocks and any extra food it has gathered.

Sea otters have been observed to be incredibly innovative and impressive. One study noted that even stranded juveniles that were reared by humans spontaneously developed a knowledge of stone tool use.

Interestingly, otters are also known to be very particular when choosing their rocks, often opting for stones within a specific size range.

Different otters may also display varying preferences for rocks of different shapes, textures or weights.

It is common for otters to have favourite rocks and even pass these "collections" down to their offspring, much like a family heirloom.

These rocks play a significant role in the otter's life beyond serving as a practical mealtime tool – otters have been observed grooming their rocks, self-soothing by rubbing the rocks against their body, as well as juggling and playing with their collections.

The exact reasons behind such behaviours are still being studied, with some scientists purporting that frequent interaction with rocks helps otters maintain their dexterity.

Other scientists think the animals are just having fun!

References:

1. https://animalqueries.com/do-sea-otters-collect-rocks/

2. https://oceantoday.noaa.gov/seaotteranatomy/

3. https://www.sciencedirect.com/science/article/abs/pii/S0006320707001796?via%3Dihub

4. https://www.aquariumofpacific.org/blogs/comments/chloe_the_sea_otter_demonstrates_otter_pockets

5. https://www.smithsonianmag.com/smart-news/hungry-otters-juggle-behaviors-function-remains-mysterious-180974837/