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Surviving Wild: Diet of the American Mustang

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America’s wild horses have adapted to surviving on native grasses and shrubs available. We know they eat, but the question is, what do they eat? The answer to that varies depending on the region but can be broken down into three main components.

(source)

What do wild horses eat? According to a University of Wyoming rangeland study, wild horses eat a combination of grasses, shrubs and forbs. The percentage breakdown for each is:

  • 82% Grasses
  • 8% Shrubs
  • 10% Forbs

I know you may be wondering, what is the difference between a grass, a shrub and a forb? Let’s have a look!

Grasses

Plants are classified as grasses when they have narrow leaves with parallel veins. On wild rangelands, these grasses may look more like weeds. The fact of the matter is, lawn grass isn’t particularly nutritious and wouldn’t really work as a long term forage for horses. A variety of species of grass are abundant on the rangeland and help to provide nutrition to wild horses.

Let’s have a look at some of the types of grasses you might find where wild horses roam in the United States.

Idaho Fescue Grass

Idaho fescue is one of the most desirable range grasses due to its ability to produce a lot of seed and withstand heavy grazing. It is palatable and nutritious for most grazing speecies including horses and cattle. (source)

Idaho Fescue Grass - Matt Lavin from Bozeman, Montana, USA [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]
Photo by Matt Lavin from Bozeman, Montana, USA [CC BY-SA 2.0], via Wikimedia Commons

Needle Grass

Needle grass is sometimes also called “Purple Stipa” or “Purple Tussockgrass”. It is a great rangeland grass because of its ability to thrive on disturbed areas and poor soils. It withstands drought and can grow in full sun or partial shade. (source)

Purple Needlegrass along with mountain dandelion, owls clover and other grasses. Pacific Southwest Region USFWS from Sacramento, US [Public domain], via Wikimedia Commons

Squirrel Tail Grass

Squirrel tail grass is another great rangeland grass often consumed by wild horses. Pet owners, particularly, might recognize this plant as the “foxtail weed”.

Squirrel tail grass is successful on the range due to its ability to germinate at a wide variety of temperatures and compete with cheatgrass. It is palatable to horses, cattle and sheep in the spring before the seed head, or foxtail, develops.

Squirrel Tail Grass – Dcrjsr [CC BY 4.0], via Wikimedia Commons

Bluegrass

Bluegrass is one of the rangeland species that actually works pretty well as a lawn grass as well. Most commonly we hear about “Kentucky Bluegrass”. Horses and cattle are very fond of this type of grass as it is highly palatable (very yummy).

Kentucky bluegrass does go dormant in very hot conditions but can survive sever droughts. It’s resistance to heavy use makes it one of the favorite grasses for high traffic situations like baseball fields. (source)

Kentucky Bluegrass Stem – Ryan Hodnett [CC BY-SA 4.0], via Wikimedia Commons

Great Basin Wild Rye

The USDA describes basin wildrye as a large, robust perennial bunchgrass. This grass can reach 6′ in height and 3′ in diameter. It is a grass that is native to the great plains.

Basin wildrye is palatable to all types of grazing animals and wildlife including horses, burros and cattle.

Great Basin Wildrye – Matt Lavin from Bozeman, Montana, USA [CC BY-SA 2.0], via Wikimedia Commons

Shrubs

Shrubs are pretty easy to spot on a wild horse range. If it looks like a bush (big or small) it is probably a shrub. They are woody plants with multiple stems that are typically low to the ground. Though, in some areas, shrubs can be over 6′ tall.

Most horses are going to prefer to eat grasses whenever possible. Forbs are the next favorite and shrubs seem to be last on the list of preferred foods. If you think about the difference between grasses and shrubs, it makes a lot of sense.

Which would you prefer to chew on: a nice, soft patch of grass or rough, woody shrubs? I think we know why horses prefer grass. When they need to, however, they can eat shrubs. Some of the common shrubs available for wild horses to eat include:

Big and Low Sage

There are a wide variety of subspecies of sagebrush but they all have generally the same look. They typically grow between 2 and 4 foot tall in vast communities. Some, however, can reach over ten feet tall if the right conditions are present.

Sagebrush does well on the open range because of its ability to grow in hot, dry summers as well as in areas with strong winds. While this shrub is not as palatable as grasses, it can be consumed when food is scarce. (source)

Big Sagebrush Steppe – Matt Lavin from Bozeman, Montana, USA [CC BY-SA 2.0], via Wikimedia Commons

Bitterbrush

This shrub is native to the western United States where wild mustangs typically roam. It is a plant that is well adapted to desert life and very hardy. It can be identified by its small yellow flowers when in bloom. (source)

Fun Fact: The bitterbrush is a member of the rose family!

Bitterbrush – Dcrjsr [CC BY-SA 3.0], via Wikimedia Commons

Juniper

Juniper is an interesting species when it comes to rangeland management. In some areas, like California, it is a native shrub. In some areas though, like parts of Oregon, it is considered an invasive shrub and actually cut back as part of rangeland management strategies. (source)

California Juniper – Robb Hannawacker, while working for Joshua Tree National Park [Public domain], via Wikimedia Commons

Greasewood

Greasewood is a thorny shrub with succulent like leaves. It can be anywhere from 3 to 7 feet tall and is used as a nutrition source by wildlife such as pronghorns and prarie dogs. (source)

Greasewood – Cory Maylett [CC BY-SA 4.0], via Wikimedia Commons

Saltbrush

Saltbrush is a member of the goosefoot family of shrubs and is common to the great plains and southwest desert.

Fun Fact: Saltbrush was often used by Native Americans to make yellow dyes and the seeds of the plant were used to make flour. (source)

Saltbrush – Matt Lavin from Bozeman, Montana, USA [CC BY-SA 2.0], via Wikimedia Commons

Forbs

It is quite possible you have never heard the word “Forb” before, and certainly not in relation to horse food.

Forbs are plants that commonly have pretty flowers and net-like veins on their leaves. Think about looking over a beautiful prairie full of grasses and wild flowers. Many of those wild flowers are probably forbs. Research has shown that a wild horses diet will typically contain around 10% forbs.

Some examples of forbs that grow on the range where wild mustangs roam include:

Scarlet Globemallow

This beautiful perennial is native to the Great Plains and western United States. It is one of many forbs that can often be found where wild horses roam. This particular variety is also a popular drought tolerant plant for home landscape design.

Scarlet Globemallow – USFWS Mountain-Prairie [Public domain], via Wikimedia Commons

Indian Paintbrush

Another beautiful forb, there are different varieties which can be found throughout the United States. The most common varieties make their home in the eastern states. Different species of Indian Paintbrush may also be referred to as clovers. (source)

Indian Paintbrush – Phil Whitehouse from London, United Kingdom [CC BY 2.0], via Wikimedia Commons

Area Specific Wild Horse Diets

Let’s look at some of the common regions where wild horses roam and the grasses and shrubs available for them to eat in those locations.

Please note that this list is by no means comprehensive. In fact, it should be considered just a small sampling of what may be available in each state. The plants listed below were what I was able to ascertain from the BLM website but they rarely list the grasses for each HMA.

More information can be found on the BLM website.

Wild Horse Diets in Arizona

Arizona may seem like one giant desert but it does actually have various types of ecosystems depending on the area. According to the BLM, wild mustangs in Arizona could browse on:

  • Indian Wheat
  • Various Summer and Winter forbs
California Department of Fish and Wildlife from Sacramento, CA, USA [CC BY 2.0], via Wikimedia Commons

Wild Horse Diets in California

There are several herd management areas (HMA’s) that have wild mustangs in the state of California. While each range will have it’s own unique mix of vegetation available, we can look at some of the generally available vegetation.

According to the BLM, some of the vegetation available to wild horses in California includes:

  • Juniper
  • Bitterbrush
  • Big and Low Sage
  • Bluegrass
  • Squirreltail
  • Needlegrass
  • Idaho Fescue

Wild Horse Diets in Colorado

Colorado’s wild horses typically graze on the following:

  • Sagebrush
  • Pinion Juniper
  • Bunchgrass
  • Saltbush

Wild Horse Diets in Idaho

Wild mustangs in Idaho may consume the following:

  • Sagebrush
  • Threadgrass
  • Indian Ricegrass
  • Thurber Needlegrass
  • Wheatgrass

Wild Horse Diets in Montana-Dakotas

These states are home to the famous Pryor Mountain wild horses. There is a protected refuge for these mustangs and forage can often be limited. Some of the plant species Pryor Mustangs may graze on include:

  • Mountain Mahogany Shrub
BLM Nevada [CC BY 2.0], via Wikimedia Commons

Wild Horse Diets in Nevada

Nevada is home to many different populations of wild mustangs. They can be found throughout most of the state. Wild horses in Nevada might eat any of the following:

  • Salt Desert Shrub
  • Sagebrush
  • Winterfat
  • Pinyon Juniper
  • Rabbitbrush
  • Bluebunch Grass
  • Wheat Grass
  • Squirreltail
  • Needlegrass
  • Bottlebrush
  • Bitterbrush
  • Bluegrass
  • Milkvetch (forb)
  • Arrowleaf Balsamroot (forb)
  • Lupine (forb)
  • Phlox (forb)
  • Aster (forb)

Wild Horse Diets in New Mexico

New Mexico doesn’t have a lot of wild horses. According to the BLM, the total population is usually around 90 horses for the state. These horses might eat:

  • Pinon-Juniper
  • Black Grama
  • New Mexico Feather Grass
  • Blue Grama
  • Galleta
  • Bottlebrush
  • Squirreltail
  • Indian Ricegrass
  • Mountain Mahogany
  • Sand Dropseed
  • Cholla

Wild Horse Diets in Oregon and Washington

Oregon is most famously known for the South Steens HMA but there are actually quite a few different herd management areas (HMA’s) spread throughout Oregon and Washington. Horses in these areas might consume:

  • Sagebrush
  • Bunch Grasses
  • Cheatgrass
  • Medusa Head Rye
  • Bluebunch Wheatgrass
  • Thurber’s Needle Grass
  • Bottlebrush
  • Squirreltail
  • Sandberg Bluegrass
  • Numerous Forbs

Wild Horse Diets in Utah

There are 19 different HMA’s in Utah. The wild horses found in Utah may graze on:

  • Sagebrush
  • Juniper
  • Mountain Fir
  • Ricegrass
  • Wheat Grass
  • Blue Grass
  • Squirrel Tail
  • Salt Desert Shrub
SteppinStars [CC0], via Wikimedia Commons

Wild Horse Diets in Wyoming

Wyoming is home to 16 different wild horse HMA’s. The wild horses in Wyoming can often choose from the following foods:

  • Sagebrush
  • Greasewood
  • Saltbrush
  • Juniper
  • Indian Rice Grass
  • Wheat Grass
  • Sedges
  • Needlegrass

Related Questions

How do researchers determine what horses eat in the wild? Most studies rely on fecal analysis to determine what the horses have been meeting. Basically, this information was brought to you by dedicated researchers who analyzed lots and lots of horse poop.

What do wild horses drink? Each wild horse rangeland has water sources available for the animals that live there. In severe drought conditions, mustangs may have to travel miles each day to find water. In some areas, the BLM has installed equipment to catch rainwater and provide supplemental water.

What kind of meat do wild horses eat? While horses have been observed eating meat, it is not a staple of their diet. On rare occasions, wild horses may sample or even consume dead animals if they come across them.

What do wild horses eat in the winter? While grasses are the preferred forage for horses, in the winter, horses may have to resort to eating shrubs for the major portion of their diet.

Is it illegal to feed wild horses? It is illegal to feed wild horses and burros. If you see a wild horse or burro in need of assistance, contact the BLM and they can take appropriate action.

Do horses eat their babies? No, horses do not eat their babies.

If you would like to learn more about mustangs, check out these other helpful articles:

April Lee

I've owned horses for 25 years and have a particular love for gentling wild horses. I write these articles to help others learn more about horses. If you enjoyed the article please take a moment to pin it to Pinterest or share on social media. It really does help! Check out my about page for more detailed information.