Like cats, killer whales are renowned for playing with their food. They appear to have invented the frisbee game to avoid being stung by the rays' barbed tails. The strange behaviour was observed by Ingrid Visser, a research student at Auckland University, who spent two years studying killer whales off New Zealand.
She watched 19 whales, mostly male, pursue and eat 55 stingrays, some of which measured two metres across. On one occasion two whales ate 18 stingrays in a six-hour binge.
Normally one killer whale would dive down to find a ray on the sea bed and then signal the others. Ms Visser had observed whales in water as deep as 120ft, often doing headstands.
The study was reported in New Scientist and said: "Sometimes a whale flips the ray out of the water before tossing it around like a Frisbee with at least one other whale. Visser says this may be an attempt to reposition the ray so the whale can eat it without being stung."
It was also thought adult whales may use the game to show youngsters how to tackle dangerous prey.rReuse content