Makers of all things moving and dancing.  Animators should first and foremost have an excellent grasp of the anatomy and motion of whatever they’re animating (humans are a traditional starting point), along with the 12 principles of animation.  Having knowledge of at least one 2D and one 3D package is also recommended.
Animators may additionally be in charge of the animation of props such as vehicles, or even specialize in these at certain studios.  Depending on the studio they may be in charge of rigging as well, or it may be the job of a dedicated rigger or more general technical artist.