Yes, mice eat grass, but it is not the favorite food of this little animal. Usually these animals, which live in a natural environment, feed on cereals, stems of cereals, seeds. They like any vegetable food – fruits of trees, seeds of grasses and all that can be obtained from the plant.
If this rodent lives near human habitation, then its menu is much more diverse. Here already in food goes and bread, and vegetables, and sausage – the mouse is not capricious in the choice.
It also happens that mice eat their weak cousins, but this happens if the mice are locked together in a cage and there is nowhere to take food. So do the rats.
If you managed to buy a mouse as a pet, then you can feed it with cereals, bread, cheese, vegetables, as well as any vegetable food, but it is better to stick to a diet that is close to the natural nutrition of these animals. Feed your pet once a day, overfeeding for these crumbs is fraught with diseases.