Regardless of their age, otters have a peculiar habit that sets them apart: they carry a favorite stone with them throughout their entire lives. You’ve probably seen in photos or videos how these adorable creatures swim on their backs, holding something in their front paws.

Often, this can be their food or even their offspring. The truth is, the skill with which they manipulate objects while staying afloat is undeniable. But sometimes, what they take such good care of is a stone, their favorite stone.

Why do otters have a favorite stone?

This is the question that many biologists ponder as they watch otters choose and hold onto the same stone for their entire lives. Susan Milius, an expert in Life Sciences, dismisses the idea that otters simply play with stones just to appear cute. She argues that otters’ movements resemble more of a rocking motion with their front paws than a simple graceful tossing of objects. She expressed this in an interview with Science News.

However, the question remains: Why do otters choose a single stone to keep? According to the same specialist, this could be a form of training that prepares them for the challenges they will face in their environment.

Otters in their habitat must be ready to crack open mollusks, extract crustaceans from their shells, or tear into the carcasses of their prey to feed. Since they have relatively short claws, they need to constantly improve their dexterity to survive in their environment.

In this way, it is plausible that playing with stones is an evolutionary necessity for their species, allowing them to keep their claws sharp and be prepared for any survival opportunity.

Many unanswered hypotheses

Although this theory could explain the peculiar behavior of otters, it is only one of several that exist. There is still not enough evidence to confidently assert which one is correct.

From an evolutionary perspective, play in the animal world generally does not serve a practical purpose or satisfy an immediate survival need. Gordon Burghardt, a researcher at the University of Tennessee, suggests that otters are likely to do it “simply for fun, out of boredom, or for both reasons,” rather than as a direct need for survival.

This could explain why otters, regardless of their age, continue to perform these characteristic movements with their favorite stones.

In any case, it is extremely curious to see how these endearing animals go to great lengths to preserve their favorite stones, guarding them jealously. Although we don’t know why they do it, perhaps we should just let them have fun with them.