If you encounter a situation which requires you to transfer animation, for example copying a pose or segment of animation from one scene to another, transferring all the animation from a broken rig to a new rig, from a corrupted scene to a new scene, or from one character rig to another entirely different character, a good way to do it is using Maya's built in ATOM tool.
You can find the ATOM tool in Maya 2013 to 2015 in the Animation menu set under “Animate > ATOM”, and in Maya 2016 under “File > ATOM”.
The first step to transferring your animation is to Export your original animation in order to use it later on. You can find the process here:
Once you have your original animation exported, you can now Import it onto a new rig or into a new scene by following these steps.
If you'd like a video demonstration on this process, you can find one below:
For more information on the specific settings of the ATOM tool, you can find explanations on the Maya Help website.
There is also a video tutorial created by Beau Pratt on how to use the ATOM animation transfer tool which you can find below: