Otters juggle stones when hungry according to new Exeter University research
Captive otters juggle stones when they are hungry according to the latest research.
The University of Exeter has carried out an extensive study into the activity commonly referred to as “rock juggling” to try and establish why it happens.
The dextrous mammals are often seen lying on their backs and batting the stones into the air, catching them and rolling them around their chests and necks.
Watch the otters in action:
Experts had suggested the behaviour might help the animals practise the foraging skills they need to extract foods from complex prey such as mussels and clams.
But this study found that it could be excitement for food that drives the behaviour because otters juggle more when hungry, in anticipation of feeding times.
The team set the otters a series of food reward tasks to solve in order to see whether the otters that juggled more frequently were faster at solving them.
They also investigated whether sex, age and hunger levels could explain why some otters juggled more than others.
In turns out that both juvenile and senior otters juggled more than adults - it aides pups' development and potentially keeps the brain active in seniors.
Otter parents may have been juggling less as they did not have the time while looking after their pups.