If you’ve ever seen otters romping at the zoo, sometimes it looks like they’re juggling little rocks.
But they wanted to knowwhy otters might feel the need to do it, what function it served, if it was beneficial and what factors might influence their behavior.
The researchers observed captive Asian small-clawed otters and smooth-coated otters practicing rock juggling over six months.
They studied 50 otters across three zoos in the United Kingdom, with ages ranging from 3 months to 19 years old. Only six of the otters studied were smooth-coated otters because they are more rare than small-clawed otters in captivity.
The two different types of otters are related, but they differ in key areas, inclulding their diets. Asian small-clawed otters eat shellfish and crabs, while smooth-coated otters pursue fish.
The otters showed a variety of rock jugglingbehaviors, sometimes engaging in the activity on land. At other times they would take pebbles to the edge of the pool.
The researchers created three different food puzzles in order to test if the juggling otters were better and more dexterous at retrieving food. Some captive otters have never encountered mussels or clams and wouldn’t know what to do with them. But they are used to receiving puzzle objects for enrichment, like plastic containers they can open.
The food puzzles included tennis balls with holes cut in them, medicine bottles and Lego Duplo bricks.
« We wanted to try and replicate foraging behaviours as best as we could, » said Mari-Lisa Allison, study author and researcher and recent graduate from the University of Exeter’s College of Life and Environmental Sciences, in an email to CNN.
« With the Duplo bricks being stacked on top of one another with minced meat stuffed between each brick, we hoped that this would mimic having to extract foods from mussels [and] clams by prying them open, » Allison said.
