Skip to main content
It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
sdzglibrarybanner San Diego Zoo Global Library

Pronghorn (Antilocapra americana) Fact Sheet: Physical Characteristics

Pronghorn (Antilocapra americana)

Physical Characteristics

Body measurements

Attribute Males Females
Weight 42-59 kg (93-130 lb) 40-50 kg (88-110 lb)
133.8-149.4 cm (52.7-58.8 in)
128.3-148.6 cm (50.5-58.5 in)
Tail Length 8.3-13.5 cm (3.3-5.3 in) 8.6-12.7 cm (3.4-5 in)


Data on body measurements from Tables 20 and 22 in Chapter 5 of O'Gara and Yoakum (2004). Values reported are means from study populations across western North America.

General Appearance

Coloration and Patterns

  • Upper body and outside of legs light tan or reddish tan; chest, belly, inner legs, cheeks, lower jaw, sides, and rump patch are white
  • Two broad white blazes across the throat. Male has broad black band from eyes down the snout and a black neck patch
  • Rump patch is a large circular patch of white hairs 7 to 10 cm (2.8 to 4 inches) long, which can be erected as a signal
  • Long black eyelashes help protect the eyes from the sun.


  • Having forked or branching horns is a distinguishing feature of the Antilocaprid family. (Davis 2007)
  • Both sexes carry horns. About 70% of females have horns, which may be stunted or undeveloped
    • Females may have horns with no sheath
  • Male horns 30 to 50 cm (11.8 to 19.7 inches); female horns, if present, seldom more than 7.5 to 10 cm (3.0 to 3.9 inches)
  • Developed by three years of age
  • Black and composed of a permanent, bony interior knob covered by a keratinous sheath, which is shed annually like antlers
  • Lyre shaped, curving back and slightly inward near conical tips, each with one broad, short prong that juts forward and slightly upward, usually halfway from the base
  • Used in male competitions during the rut, using thrusts and counter thrusts to try to gore opponents
    • Prongs used to catch the thrust of opponent's horn and also to deliver serious piercing stabs.


  • Short hairs that stand on end, about 7 to 10 cm (2.8 to 3.9 inches) long
  • Reduced or absent in mexicana subspecies


  • Large, protruding eyes that appear to be located on the side of the head but are oriented forward enough to allow limited binocular vision
  • Largest eyes of any North American ungulate in relation to its size; each eyeball is about 36 mm (1.4 inches) in diameter
  • Nearly a 300-degree arc of vision without moving head or eyes; can detect movement up to 6.5 km (4 miles) away
  • See movement more clearly than stationary objects


  • Pointed double hooves, with cartilaginous padding to cushion shock in running over hard ground and rocks
  • Front hooves are larger than back ones and carry most of the weight while animal is running
  • Females strike with front hooves during agonistic encounters
  • Both sexes have glands on the feet that secrete an oily conditioner for the hoofs.

Sexual Dimorphism

  • Males average 10 percent larger than females
  • Males have longer horns
  • Black face and neck markings are not present in females

Other Physical and Physiological Characteristics

Adaptations for long-distance running and endurance

  • Long limbs with reduced number of toes
  • Lightweight bones
  • Small digestive tract to use less energy during locomotion
  • Large tracheae, lungs, heart for rapid intake of oxygen and increased rate and power of circulation.

Genetic characteristics

  • Variable number of chromosomes; the diploid number is 58 or 60 (Wurster and Benirschke, 1968; O’Gara & Yoakum 2004).
  • Antilocapridae shows genetic similarities to both Bovidae and Cervidae.
    • Studies showed the chromosome number and configurations in pronghorn similar to bovids (Todd 1975; Baccus et al 1983)
    • Baccus et al. (1983) maintained that the pronghorn is genetically similar to cervids.
  • DNA investigations indicate Antilocapridae is a legitimate family of its own (Cronin et. al, 1996).
  • Occasional specimens have extra horns or teats, females may or may not have horns, and some females have a different type of uterus than others (O’Gara, 1968).

What's in a Name?

Pronghorn face

Pronghorn have forked or branching horns, with a forward-pointing tine, setting them apart from antelopes and bovids (cattle, sheep, buffalo, etc.).

The only suriviving member of Antilocapridae, they are unique in the animal world.

Image credit: © San Diego Zoo Global. All rights reserved.

A White Sight

the white rump of an American Pronghorn

The pronghorn's distinctive white rump.

This female has small horns compared to the male pictured above.

Image credit: © San Diego Zoo Global. All rights reserved.

Page Citations

Byers (1997)
O'Gara (1978)
O’Gara & Yoakum (2004)

SDZG Library Links