There are two ways to copy animation layers. You can copy an animation layer to create a duplicate layer with the same objects and attributes, or you can copy a layer to create a duplicate with the same objects, attributes, and animation.
To copy an animation layer with its animation
Depending on which option you choose, a layer is created either containing the same objects, attributes, and animation or only the same objects and attributes (but no animation). It appears below the selected layer in the stack.