Gray brocket deer are mostly frugivorous, especially during the wet season (November to February). They focus on soft, fleshy fruits available from bush-like trees. During the dry season they feed more on the mast crops from the trees of Zyzyphus oblongifoia and Casesalpinia paraguarensis (February thru October). These trees produce dry, tough fruits, which become scarce during the wet season. In a region such as the chaco, water stress is more apparent during the extended dry season, resulting in the deer eating more cacti and bromeliad fruits, as well as succulent leaves and roots to satisfy water requirements. Gray brocket deer are also grazers and a browsers. They utilize roots, twigs, flowers, buds, bark and leaves of trees and shrubs, some seasonally and other annually. (Stallings, 1984)
- Stallings, J. 1984. Notes on the feeding habits of Mazama gouazoubira in the Chaco Boreal of Paraguay. Biotropica, 16: 155-157.