I'm a walking, climbing animal; deer are running, jumping, swimming animals.

我是一只行走、攀爬的动物；鹿是跑、跳、游泳的动物。

NARRATOR: In the arboreal scenario, the bird ancestor was a small climbing animal that evolved flight by gliding from the treetops.

旁白：在树栖场景中，鸟类祖先是一种小型攀爬动物，通过从树顶滑翔进化出飞行能力。