You can choose to copy an animation layer using the Duplicate button, the context menu options, or the keyboard shortcuts. 
To copy the animation layer using Duplicate:
- Select the animation layers you want to copy. 
 
- In the Key Controls window, select a layer from the Layer menu to make it current. 
The current layer displays bright green in the Animation Layer editor. 
  
- Click the Duplicate button in the Animation Layer editor toolbar. 
The newly-duplicated layers appear above the current layer in the stack and contain the keyframes of the layers you copied. 
  
To copy and paste the using the context menu:
- Select the layers you want to copy. 
 
- Right-click one of the selected layers and select Copy from the context menu. 
Tip: Select the layer and press Ctrl-C to copy it. 
  
- Right-click on the layer above which you want the new layer to appear and select Paste from the context menu. 
Tip: Click a layer and press Ctrl-V to paste the new layer above it. 
 The pasted layers appear above the current layer and contain the keyframes of the layer you copied.