Deer are obligate herbivores, which means that they only eat plant matter and struggle to digest meat. Deer primarily graze on grass and leaves, but they also eat nuts, fungi, grain and fruit. They eat small twigs in times of food scarcity.
The diet of most deer species is seasonal. During the warm months, deer rely on their preferred foods, namely, leaves and grass. Some plants that they especially like to graze on include clovers and wild beans. Oak and elm are also a big part of their diet. Deer even eat harmful weeds such as ragwood and poison ivy. During the cooler months, they eat mushrooms, acorns, cranberries and grain, especially sorghum, in addition to whatever leafy plants they can find.