in Animals

Why do otters have a favorite stone for life?

Otters are fascinating animals. They belong to a group of semi-aquatic mammals of the mustelid family.

You've probably seen them in documentaries, with their elongated bodies covered in fur that allows them to float and swim in water without getting cold. Their legs are short and strong, and their teeth are made to eat all kinds of food.

Otters are found in many parts of the world, including North America, Europe, Asia, and Africa, and they all behave in the same way: they usually carry a stone in their hands, which they play with regularly. Otters use the stones to break the shells of the crustaceans and mollusks they hunt and which make up most of their diet. But they have also been seen playing with rocks. Why do they do this?

Otters are one of the few animals that use tools, in this case stones, to reach their prey and access their food. Moreover, otters choose the stones they use carefully and can keep them on them for a long time, hiding them in the folds of their fur or in their pockets, in the case of sea otters, located in the loose skin under their front legs, so that they can use them later.

Training to hunt

A study published by the Center for Ecology and Conservation from the University of Exeter, UK, examines “the drivers and functions of rock juggling in otters.” “The movement they perform is more like a swinging motion between the front legs than an exercise in rhythmically throwing objects in the air,” the researchers explain.

Otters regularly play with rocks, regardless of age or sex.

It has been observed that the movements otters make with their favorite stone are very close to the chest, as if it were rolling. This movement resembles the one they make when they eat mollusks. So scientists have suggested that this may be a way to exercise their motor skills, perfect their dexterity and sharpen their claws. Although we are not 100% certain of this claim.

On the other hand, the study found that this behavior occurs in both young and old otters, regardless of the sex of the otter. The frequency of this behavior increases when otters are hungry. As the study indicates, this behavior may change over time and a study with wild otters is needed to confirm whether they also play with rocks for fun and because they are bored, as is the case with captive otters.