At the Leipzig Zoo, the scientists hid rewards such as grapes, banana slices or toy animals under a hollow piece of wood, an imitation bird's nest or an artificial hollow rock.
At the Leipzig Zoo, the scientists hid rewards such as grapes, banana slices or toy animals under a hollow piece of wood, an imitation bird's nest or an artificial hollow rock.
在莱比锡动物园，科学家把一些奖品，比如葡萄，香蕉片或者玩具动物，藏在一段中空的木头，一个仿真鸟巢的下面或一个中空的人工石头下面。