Ozotoceros bezoarticus
Pampas deer

The pampas deer once lived throughout the natural grasslands of eastern South America situated between latitudes 5 and 40S. Now the distribution is restricted to local populations. Jackson (1987), Nowak (1991).

The pampas deer occupies a wide variety of open grassland habitats at low elevations. These habitats include areas temporarily inundated by fresh or estuarine water, rolling hills, and areas with winter drought and no permanent surface water. In some places the grass is high enough to completely cover a standing deer. However, much of the original range has been modified by agriculture and other human activities. Jackson (1987), Nowak (1991).

Ozotoceros bezoarticus is a medium-sized, lightly built cervid. Head and body length is 110 - 140 cm, shoulder height is 70 - 75 cm. The prevailing color of the upper parts and limbs is reddish brown or yellowish gray. The face, crown, and tail are darker. Coat color is richer on the back than toward the extremities. Cream-colored areas occur as tarsal tufts, inside the ears, around the eyes, chest, throat, underparts, and underside of the tail. There is no marked difference between summer and winter pelage. Pelage of newborns is chestnut with a row of white spots on each side of the back and a second line from the shoulders to the thighs. The spots disappear by about 2 months of age, leaving a russet juvenile coat.

Males are slightly larger but there is no marked sexual dimorphism in size, weight, or pelage. Only males have antlers, that consist of three tines: a lower or front prong of the main fork and the upper or posterior prong divided. A synchronized antler cycle exits. Antlers are shed in mid winter, a new set begins to grow immediately and racks are cleaned of velvet by early summer.

It was suggested a latitudinal size gradient with northern animals larger. Three subspecies have been described based on geographic variation of the color coat. Ozotoceros bezoarticus bezoarticus is pale red-brown, O. b. leucogaster is tawny-brown, and O. b. celer is bay.

Jackson (1986, 1987), Nowak (1991), Gonzalez et al. (1991).

The home range of Ozotoceros bezoarticus is unknown, but this spcies is largely sedentary. No regular daily or seasonal movements are described. The pampas deer lives in small groups rarely exceeding 5 - 6 individuals. Most observations are of solitary animals. Groups are fluid in composition; the members, especially adult bucks, freely move from one group to another at any season. However, mother-young bonds appear strong with fawns staying with the maternal female all year. Males mix with females throughout the year. No evident habitat partitioning exists, either by sex or age. Sometimes, aggregations of up to 50 or more individuals form on common feeding grounds. When undisturbed during clement weather the pampas deer often lays on open feeding grounds to ruminate and rest. Reactions to disturbance include staring, peering, standing alert, footstamping and snorting, stilting, and tail raising. To avoid detection, the pampas deer also freezes if in cover, lies on ground, or crawls or slinks away. Agresive postures include glaring, a head-low threat and chase, striking with the forefoot, biting and antler-present threats; submisive acts include looking-away, exposing the neck, and commencing self-grooming.

During the mating season adult males compete with one another for the estrous females. They trash vegetation with their antlers and rub the scent glands on their heads and face on plants and other objects. Aggression is demonstrated by thrusting with the antlers or flailing with the forefeet. Flighting is frequent between males of equal size. There is no evidence of territoriality or of lasting pair or of harem formation. Several males may harry a receptive female simultaneously.

Pregnant females and those with neonates become secretive. Females physically defend their small young by foot stamping, snorting, feigning injury, and butting.

Jackson (1985, 1987), Jackson and Langguth (1987), Langguth and Jackson (1980).

Ozotoceros bezoarticus is herbivorous, but its exact diet is unknown. It seems that the pampas deer selects new green growth, although shrubs also are browsed and seed-heads of grasses consumed (Jackson 1987).

Ozotoceros bezoarticus competes for food and space with domestic livestock, especially sheep (Jackson 1987).

The role of Ozotoceros bezoarticus in the culture of the Indians was comparable to that played by the bison in the lives of the plains Indians of North America. Later, the pampas deer was hunted commercially for skins for exportation and stomach stones (bezoares) for pseudomedicinal use. Over 2 million skins of Ozotoceros are estimated to have been exported from Argentina in the years 1860-70, and many more were captured in other countries. Official statistics for 1880 indicate that 61,401 skins of pampas deer were shipped from the port of Buenos Aires (Argentina). Also, the pampas deer was hunted locally for food, sport, skins, and stomach stones. Jackson (1987), Nowak (1991).

Ozotoceros bezoarticus occurred in great numbers, especially on the pampas of Argentina and Uruguay. Numbers declined rapidly through loss of habitat, transmission of disease from domestic livestock, and continued uncontrolled hunting. The pampas deer is on Appendix 1 of CITES and is designated an endangered species by the IUCN. Jackson (1987), Groombridge (1993).

The taxonomic status of Uruguayan specimens is undefined, althougth an affinity with Ozotoceros bezoarticus leucogaster was suggested (Gonzalez et al. 1991). Ozotoceros bezoarticus is distinguished by well-developed hind interdigital glands. The exudate of these glands gives a pungent, persistent, onionlike smell characteristic of the species. This odor can be detected at a distance of 1.5 km, and it is particularly strong at bedding sites and along regurlaly used paths. It was also suggested that this secretion could have an alarm role during moments of danger. Histological work demonstrated that the gland has a musculature that may assist in expelling secretion (Jackson 1987, Nowak, 1991, Lannguth and Jackson 1980).