|North American Pronghorn
The pronghorn will probably always be known as the pronghorn “antelope”. It is well to be aware, however, that our pronghorn is the sold survivor of an ancient family of animals known as the Antilocapridae and is not an antelope. The true antelopes belong to the Bovidae along with oxen, sheep, goats, bison, and buffalo. In 1972, approximately 98 percent of Arizona pronghorns were found on a combination of juniper-pinyon woodland, grama-galleta plains and grama-tobosa plains. About 1% occupied Great Basin sagebrush and the remaining 1% occupied a combination of creosote-bush-bursage and paloverde-cacti. The pronghorn is a game animal in Arizona.
Order - Artiodactyla
Family - Antilocapridae
Genus - Antilocapra
Species - Americana americana
There are three sub-species of pronghorn in Arizona. Sub-species americana is found in the northern half of the state, mexicana in the southeastern quarter, and sonoriensis in the southwestern quarter. Differences are mainly slight color variations and habitat adaptations. The upper parts of the animals are reddish brown or tan with a darker brown mane on the neck. There are two broad white bands across the throat, a large white rump patch, and the underparts are white. In males, the face and a patch on each side of the head are black while in the females the mask and patch are nearly lacking. Each sex has horns. The horns are slightly curved with a single prong projecting forward. The outer shell of the horn is shed annually. The pronghorn lacks dew claws, has eleven scent glands, weighs from 100-125 pounds, and is relatively short-lived (7-10 years).
Females breed at 14-15 months, twins are common, each kid weighs about 6 pounds. Gestation period is eight months. When the kids are 3-days-old they can outrun a man. Some research has shown the coyote and bobcat to be the most important predators on antelope, especially on the young kids. Pronghorns have telescopic vision, depend little on their sense of smell, and are the fleetest of all North American game animals. Many have been clocked up to 40 mph with a few records near 60 mph. By flexing certain muscles the pronghorn can maintain its hair at many different angles. Cold air is excluded when the hairs lie smooth and flat. Hair can be raised to allow air circulation in hot weather. The hair is hollow and will break and crush easily when handled. Pronghorns breed in August and September and the young are born in May and early June. The pronghorns roam in small bands during summers but congregate in herds in the winter. Herd home range is 20 to 40 square miles.
Detailed food habit studies have not been completed for Arizona. Good information is available from Catron County, New Mexico, which borders Arizona and is closely similar to the best Arizona habitat (Juniper-pinyon). The following data was taken from the Adobe Ranch on the west end of the San Augustine Plains. Data is shown as percent of total material in antelope stomachs taken on the ranch.
Species of Plants Winter Spring Summer Fall
Grama grasses T T T T
Pricklypear & cholla 23.4 21.7 0.3 T
Yucca 0 0 T 0
Juniper 6.5 T 0.3 T
Juniper mistletoe 0.4 0 T 0
Oak 0 T T T
Fourwing saltbush 0 1.2 0 0
Squaw currant 0 T 0 0
Apacheplume T T
Skunkbush sumac 0 1.7 5.0 0
Rabbitbrush T 0 0 0
Rubber rabbitbrush 0.2 1.7 T 1.5
Carruthii sagebrush 25.5 5.8 47.0 45.4
Fringed sagebrush 42.3 45.5 13.8 1.7
Buckwheat 1.3 6.8 2.5 41.6
Purslane 0 0 10.5 0
Bladderpod T 2.5 T 0
Spurge 0 6.1 2.8 5.9
Houstonia 0.6 3.5 0.5 0.7
Snakeweed T 1.7 T 0
Zinnia T 0.5 0.2 0.2
Further studies are being made but are not complete for Arizona. Grass makes up only a small percentage of pronghorn diets with forbs and browse being the major foods.
Large basins and rolling grassy plains with scattered brushy draws and canyons and where vegetation is no higher than 24” are ideal antelope habit.
It is desirable to have one-quarter to one gallon per animal, per day for each day of the year, particularly during warm seasons.
Pronghorns reproduce and survive best on native ranges with a wide diversity of vegetative types and an abundance of forbs, browse, and grass on a yearlong basis. Some management suggestions are:
Make water available every 3 to 4 miles on open range.
Insure that water is available throughout restricted home ranges (5 miles or less).
Do not build woven wire fences on antelope ranges.
Bottom wire on all barbed-wire fences should be smooth, 16 inches from the ground and with no stays between posts. Other wires should be 10 inches apart.
Include adapted species of forbs, browse and legumes in reseeding mixtures. Do not plant single species on reseeded areas. Some suggested species are alfalfa, white and yellow sweet clover, green wheat, burnet and kochia.
Bobcats and coyotes can prey heavily on young pronghorns. Selective removal of some predators may be necessary. Contact the Arizona Game and Fish Department for guidance.
References – Part 1 – 4, 7, 8, 9, 12, 13, 35
Sundstrom, Charles. Abundance, Distribution and Food Habits of the Pronghorn.
Wyoming Game and Fish Commission Bulletin #12, 1973.
Russel, T.P. Antelope of New Mexico. New Mexico Department of Game and
Fish bulletin #12, 1964.