Entomologists and animal behavior specialists continue to wonder why otters have a favorite stone that they keep throughout their lives and with which they play affectionately. If you have ever had the opportunity to watch documentaries about otters, you may have already heard about the habit of these aquatic rodents of choosing the stone they like the most from a young age. This is a lifelong choice and a bond that has not yet been understood, but there is much speculation.
While it is true that the media has fallen into an exaggeration about how otters treat their stones, arguing that they are capable of juggling them, these animals do keep the same stone for life and play affectionately with it. It’s not about throwing it in the air and treating it like a basketball, but they do massage its little paws with them.
Experts are still trying to understand why they have this behavior, which is very touching to human eyes. It has been speculated that it is some kind of game that trains them for the challenges of everyday life. Otters make movements with their favorite stones, rolling them over their chest and small paws.
It is believed that animals with small claws, such as otters, need to develop their psychomotor skills to extract their food. These aquatic rodents feed mainly on mollusks, or other types of prey with exoskeletons. So biologists speculated that stimulating their paws through playing with stones could help them strengthen their feeding skills.
The animals have fun too
However, new research has debunked this speculation as there is not enough evidence to support it. According to Mari-Lisa Allison, from the Center for Ecology and Conservation at the University of Exeter and leader of a new study, the behavior of otters in the wild, as well as in captivity, was carefully observed. No empirical evidence was found to ensure that the development of psychomotor skills is the reason behind playing with stones.
Allison explains that in the animal world, frolicking apparently serves no evolutionary or adaptive purpose. She is also firmly convinced that it does not satisfy an immediate need for survival, so playing with stones would not have the ultimate goal of adapting otters to extract prey from their exoskeletons. In this case, the playing would have to cease as experience arrives and age advances, but it has been observed that older otters increase their bond with stones. So what is her theory?
Based on observational findings from otter behavior, Allison explains that there is a much more interesting reason behind this. Otters likely play simply “for fun, boredom, or both.” After all, it seems that animals also have fun and do not just act on their instincts, as was previously thought.
References:
Allison, M. Reed, R. Michels, E. Boogert, N. The drivers and functions of rock juggling in otters. The Royal Society. DOI