Oregon Zoo's lead zookeeper at the Predators of the Serengeti area, Beth Foster, had her African lions leaping to get hold of a long line of butcher paper tied together.Butcher paper is thick brown paper used for wrapping meat but it is also used in arts and crafts.Video filmed at the zoo showed the lions, called Kya, Neka, Hasani, Mashavu and Niara, leaping high in the air to tear pieces off the line.”We have six lions right now, it's really important for us to keep them mentally and physically fit,” zookeeper Beth Foster said.”We call it the leaping lion toy. They love it, they love it. They are really inquisitive and they have those instincts to pounce,” she added.Foster said the idea for the exercise came from toys available in pet shops