Species Highlight: Pronghorn

Text and photos by Heather Cline 

Most people who know me or have seen my work know that I am primarily a nature photographer, but what really got me interested in nature photography was wildlife. I love animals of all kinds. I enjoy watching them, learning about them, and of course photographing them!

Over the years, I pulled back from wildlife photography a bit because I didn't feel like I had the right equipment to get really good images without encroaching into their personal space so I gradually focused more on landscapes and macro work.

Earlier this year, I saw a pronghorn not far off the road an I got really excited because I hadn't seen one in years. I think it was that day that I decided I was going to Yellowstone before the year was over. Yellowstone is known as the Serengeti of North America and a good place to see pronghorn. This didn't really solve my equipment issue so I purchased a good telephoto lens and this helped boost my confidence that I could obtain good images while remaining at a respectable distance. I'm still trying to convince my husband this was a responsible expenditure!

I was fortunate during my trip to Yellowstone to see and photograph some pronghorn and wanted to share some information about them here. My goal is to educate and inspire others to appreciate these beautiful animals.  

Overview

• Pronghorns are a North American ungulate (hoofed animal). 
• The scientific name for a pronghorn is Antilocapra americana and they are the only surviving member of the Antilocapridae family.
• While they are often referred to as Pronghorn Antelope, they are not members of the goat or antelope families. The pronghorn’s closest living relatives are the giraffes and okapi. 
• The naming appendage of "antelope" started back in 1804-1806 when Lewis & Clark journeyed across North America. While antelope do appear similar to pronghorn, technically antelopes are animals that are native to Africa and Eurasia, not North America.
• Males are called bucks. Females are called does. Babies are called fawns.
• They have 300 degrees of vision and can detect movement up to 4 miles away.
• On average they live for 10 years.

Size

• Pronghorns are about 4 to 5 feet from nose to tail and stand about 3.5 feet high at the shoulder.
• They weigh between 85 and 145 pounds.
• Males are usually 10% bigger than females.

Speed & Agility

• Pronghorns are the fastest land mammal in North America.
• They are often cited as the second-fastest land animal, second only to the cheetah. However, they can sustain high speeds longer than cheetahs.
• Their average running speed is 40 MPH, but they can run at speeds of up to 60 MPH for long distances.
• Pronghorns have 13 distinct gaits - one reaches up to 20 feet per stride.
• To protect themselves when running over uneven or firm ground, they have pointed and padded double hooves.
• Pronghorns are excellent swimmers. 
• Although they are excellent runners, pronghorn are not good jumpers. If they come across a fence, they often go under it.

Horns

• Pronghorns got their name from the horns that point backwards toward their rump and then prong.
• Both sexes have horns, but the buck's horns are longer and measure 12 to 16 inches.
• The horns fall off annually, usually shortly after breeding.
• The horns of the pronghorn help make it unique: they are a cross between horns and antlers, with qualities of both. True antlers are made of bone and shed each year; true horns are made of compressed keratin that grows from a bony core and are never shed. The horns adorning the pronghorn are neither true horns nor true antlers. Instead, the sheath is made of keratin but the horns shed yearly.
• True horns have only one point, not the prongs or forks that antlers have. Yet the male (buck) pronghorn’s horns can grow to be 10 inches (25 centimeters) long with a forward-facing prong. Hence its name: pronghorn. Female pronghorn (called does) also have horns, but they are much smaller. Pronghorn are the only animals in the world that have forked horns that shed each year

Pronghorn with deformed horns

Diet

• Pronghorn are herbivores. They eat grasses, forbs, sagebrush, and other prairie plants.
• They eat the non-woody flowering plants first, if available. Shrubs, grasses, cactus, and domestic crops are also on the menu, depending on the time of year. Shrubs are important in wintertime, and pronghorn use their front feet to dig for food buried in the snow. The pronghorn's teeth are always growing, because they wear down as they grind food.
• Pronghorn digest their food twice. After they swallow food, it passes through the stomach and then the pronghorn regurgitates it. This process allows the pronghorn to break the plant material into smaller pieces so that more nutrients are absorbed. The regurgitated food is called cud.
• They seldom drink water because they receive most of their water from the plants they eat.

Social and Breeding Behaviors

• Groups of pronghorns are called bands or herds.
• All ages and sexes gather together in bands during the winter months. Bucks are territorial during the summer months. During breeding season, bucks gather harems and fight other bucks.
• They breed at about 2 years of age in late September.
• Does give birth to two grayish-brown fawns after 7-8 months.
• The newborns can take their first wobbly steps just 30 minutes after birth. At four days old, they can outrun humans, and in one week, they are able to run faster than a horse, if needed.
• The baby pronghorns depend on their mothers’ milk until they attain the age of weaning at 4 or 5 months

Predators and Threats

• Predators include cougars, wolves, bobcats, coyotes, and eagles.
• Pronghorn rarely sleep to stay alert for predators. If they do sleep, it is generally for less than 10 minutes at a time. 
• Threats to pronghorn include habitat loss, human-wildlife conflicts, and overexploitation due to historic hunting, which greatly reduced the population size.
• Early hunters of pronghorn tied handkerchiefs to poles and waved them in the air in a technique called flagging. This attracted curious pronghorn within gunshot range. Flagging is now illegal, and protection of habitat and restrictions on hunting have allowed the pronghorn to recover a bit. 
• It is thought that there were up to 35 million Pronghorns in North America at one point. That number dropped to roughly 13,000 by 1915. Today there are roughly 800,000.
• The pronghorn's 300-mile migration is grueling and requires crossing private property and fences. In the past, pronghorn had to worry about predators and cold weather. Today the bigger threats are cars, impassable fences and roads, and development.
• Of the five Pronghorn subspecies, the peninsular pronghorn is at critical risk with only 150 remaining in Baja California, Mexico. Hunting, agriculture, and cattle ranching (along with livestock fences) have led to the rapid decline of this subspecies

Pronghorn crossing the road

Range and Climate 

• Pronghorn are found in the United States in the Great Plains, Wyoming, Montana, northeast California, southeast Oregon, Nevada, Utah, Colorado, Arizona, and New Mexico.
• Pronghorn like open plains, fields, grasslands, brush, deserts, and basins.
• Their habitat ranges from sea-level to about 11,500 feet.
• Between the summer and winter, pronghorn migrate between feeding grounds to survive the harsh winter.
• Pronghorns have hollow hair that helps to insulate them from the cold.
• They can survive in temperatures ranging from -50 to 130 F

Migration

• Pronghorn have the longest land migration in the continental United States
• The migration depends on where the pronghorn lives. Some do not need to migrate because the nearby land has plenty of food all year. Other large herds make a 300-mile roundtrip migration.
• In November, the Wyoming Pronghorn start migrating south in small herds from Grand Teton National Park across government land, private lands, and ranches. If they make it to the Upper Green River Valley, then the pronghorn will make the journey back north to greener pastures in April.

I hope you enjoyed this focus on the magnificent pronghorn and are lucky enough to see them in the wild on your next adventure.