They are most active at dawn and dusk as they browse and graze on a variety of plants. They eat the non-woody flowering plants first, if available. Shrubs, grasses, cactus, and domestic crops are also on the menu, depending on the time of year.
Shrubs are important in wintertime, and pronghorn use their front feet to dig for food buried in the snow. The pronghorn’s teeth are always growing, because they wear down as the animal grinds its food. They drink when water is available, but they can go for weeks without it, getting moisture from their food.
During fall and winter, pronghorn live in large herds of up to 1,000 individuals. Each buck gathers three or four does in a small harem within the larger herd. Breeding takes place in September and October, with bucks defending and marking territories.
Often, more dominant bucks have better territories with better food supplies to attract the does. Yet the females decide which males they want to breed with. They often stay with one male for a day or two before moving on to another to assess his fitness. Fawns born in the same litter often have different fathers.