Mule deer (Odocoileus hemionus) fawn resting in someone’s backyard, chewing it’s cud.
Mule deer are primarily browsers, with a majority of their diet comprised of forbs (weeds) and browse (leaves and twigs of woody shrubs).
Deer digestive tracts differ from cattle and elk in that they have a smaller rumen in relation to their body size, so they must be more selective in their feeding. Instead of eating large quantities of low-quality feed like grass, deer must select the most nutritious plants and parts of plants.
Because of this, deer have more specific forage requirements than larger ruminants.