Also, if a bowl is too deep, the cat may take the food out for convenience. A wider, shallower bowl will probably eliminate this behavior. When a cat kills prey, it bites down quickly several times. When falling, the cat uses its tail to right itself and swivels its body in mid-air, so that it is facing the ground, and lands with its back arched to absorb the shock. Cats have very flexible bodies, so the swiveling is easy for them to do.
Cats use their tail to communicate their mood.
It could be that the grass helps the cat get rid of fur swallowed while grooming, or that grass provides fiber or vitamins and minerals not found in meat.