Their habitat includes water and hills, often with winter drought, and grass that is high enough to cover a standing deer.

[4] Many of them live on the Pantanal wetlands, where there are ongoing conservation efforts, and other areas of annual flooding cycles.

[5] 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.

The Pampas deer evolved as a plains animal; their direct ancestor first appeared during the Pleistocene epoch.

It is possible that with the general decline of these predators, Pampas deer have evolved to be less fearful, a potential detriment to the species' longevity.

Males have small, lightweight antlers that are 3-pronged, which go through a yearly cycle of shedding in August or September, with a new grown set by December.

[3][4] When they feel they may be in danger, they hide low in the foliage and hold, and then bound off about 100–200 meters, often looking back at the disturbance.

Females with a fawn will fake a limp to distract a predator, or if they are unsure of a situation, such as if a human appears.

Although this is endearing to observers, their lack of fleeing at the sight of humans makes them easier for poachers to kill.

The pampas deer eat less grass and more forbs (flowering broad leafed plants with soft stems) and browse (shoots, leaves, and twigs), respectively.

[4] The Pampas deer of southern Argentina, once very abundant, are now considered a threatened species by the IUCN.

Their overall decline is also due (in part) from hunting and poaching, but also from agricultural habitat loss (thus exposing deer to diseases from domesticated and feral livestock), competition from more recently-introduced wildlife, and general over-exploitation.

Lack of funding and technology have made it difficult for biologists to track and aid the deer population, while donations and grants from organizations and universities in the United States have helped immensely with the situation.

[8] Local people often blame the deer for outbreaks of disease in their livestock, particularly Brucellosis in cattle.

The individuals were monitored over a period of 4–18 days, for researchers to collect data on their movements, and thus understand how to better help them.

In the 1860s, documents for the Port of Buenos Aires indicate that some two million Pampas deer pelts were sent to Europe during the decade, alone.

Many years later, as infrastructure was being built throughout the pampas, roads and automobiles made hunting even easier.

Both countries have declared the species to be a "natural monument" and yet the hunting continues, albeit somewhat less frequently.

The deer were revered; not only were they hunted, their carcasses blessed, and spirits thanked for their sacrifice, but the entire animal would be utilized for food, building materials, weapons, clothing, medicine, and more.

Historically, the native peoples of northern Argentina, Paraguay and Uruguay participated in the sale of Pampas deer pelts for export, and yet the animals persevered until European powers ultimately took over.

The settlers brought with them mass agricultural expansion and uncontrolled, unregulated hunting of wildlife, as well as new, lethal pathogens with the arrival of domesticated livestock.

[4] Escaped farm animals formed feral populations, thus competing with the Pampas deer and other local species for resources, in addition to exposing them to potential new diseases.

Some landowners have set aside areas of their properties as undisturbed or native habitat for the deer, as well as keeping cattle instead of sheep or goats; sheep and goats compete more directly with the deer as they also browse on shrubbery and tall vegetation, far more than the grazing cattle.