Pampas deer, Ozotoceros bezoarticus, live in the grasslands of South America at low elevations. They are also known as Venado or Gama. Their habitat includes water and hills, often with winter drought, and grass that is high enough to cover a standing deer. Many of them live on the Pantanal wetlands, where there are ongoing conservation efforts, and other areas of annual flooding cycles. Human activity has changed much of the original landscape. They are known to live up to 12 years in the wild, longer if captive, but are threatened due to over-hunting and habitat loss. Many people are concerned over this loss, because a healthy deer population means a healthy grassland, and a healthy grassland is home to many species, some also threatened. Many North American birds migrate south to these areas, and if the Pampas deer habitat is lost, they are afraid these bird species will also decline. There are approximately 80,000 Pampas deer total, with the majority of them living in Brazil.

The Pampas deer are part of the New World deer, another term for all South American deer species. Fossil records indicate that New Word deer traveled to South America from North America as part of the Great American Interchange around 2.5 million years ago, following the formation of the Isthmus of Panama. It is believed that they rapidly evolved into different species, with only a few surviving today. Due to the large continental glaciers and the high soil acidity in areas where there were no glaciers, a huge part of the fossil record has been destroyed, so there is no indication what the New World deer used to look like. Fossil records begin with clear differentiation and are close to what they currently look like. The Pampas deer evolved as plains dwellers. Their direct ancestor first appeared during the Pleistocene period (the Ice Age) during the Pampean Formation.

The Pampas (from Quechua pampa, meaning "plain") are fertile South American lowlands, covering more than 750,000 km² (289,577 sq mi), that include the Argentine provinces of Buenos Aires, La Pampa, Santa Fe, Entre Ríos and Córdoba, most of Uruguay, and the southernmost Brazilian State, Rio Grande do Sul. These vast plains are a natural region only interrupted by the low Ventana and Tandil hills near Bahía Blanca and Tandil (Argentina), with a height of 1,300 m (4,265 ft) and 500 m (1,640 ft) respectively. The climate is mild, with precipitation of 600 mm (23.6 in) to 1,200 mm (47.2 in), more or less evenly distributed through the year, making the soils appropriate for agriculture. This area is also one of the distinct physiography provinces of the larger Paraná-Paraguay Plain division. These plains contain unique wildlife because of the different terrains around it. Some of this wildlife includes the rhea, the pampas deer, several species of armadillos, the pampas fox, the White-eared opossum, the Elegant Crested Tinamou, and several other species.