The mule deer is a small, intermediate, ruminant feeder with limited ability to digest highly fibrous roughage and feeds on leaves, twigs, acorns, legume seeds, fleshy fruits, berries, and drupes.
The mule deer is a small ruminant with limited ability to digest highly fibrous roughage. Based on its stomach structure and its diet of woody and herbaceous forage in approximate equal proportions, the mule deer is classified as an intermediate feeder.
Mule deer frequently browse leaves and twigs of trees and shrubs. Green leaves are very succulent and, except for epidermal tissue and structural ribs, consist largely of easily digestible cell contents. Dead and weathered leaves have little protein and high cell-wall values. As a result, they are of very low digestibility. Mule deer also eat acorns, legume seeds, and fleshy fruits, including berries and drupes that have moderate cell-wall levels and are easily digested.
Optimum growth and productivity of individuals and populations are dependent upon adequate supplies of highly digestible, succulent forage. Diets consisting primarily of woody twigs cannot meet the maintenance requirements of the mule deer.