Feral horses

Horses (Equus caballus / Equus ferus caballus) are found living a wild way of life in many parts of the world with little human intervention, or none at all. There is little discussion between scientists as to the domestic origin of most of these free ranging horse populations, although some do defend theories of non-domestic origin.

For those that consider that all extant wild living populations of horses indeed descended from domestic horses, the term used to describe them is “Feral” and below some examples of its scientific usage:

“The majority of the apparently wild populations around the world are in fact feral. That is they are domestic animals which have returned to the wild” Kiley-Worthington (1987)

“Feral horses are those whose ancestors or who themselves were domestic stock, but have been free running for some time” McDonnell (1999)

“A number of other populations of free-ranging horses or ponies like these at Assateague are found throughout the world. Some live on Islands while others rom over inland regions. Some populations have been studies by scientists, others remain unstudied. All these populations consist of feral animals, animals that have been domesticated but have since returned to the wild. There are no groups that have never been domesticated, and thus there are no truly wild horses in existence.” Keiper (1985)

“Historically, romantic names such as Mustang and Cayuse in North America, Brumby in Australia, and Cimarron, Begual, or Monstreco in South America were applied to free ranging horses. Today’s horses regardless of nomenclature are feral animals whose ancestors were once domesticated.” Berger (1986)

The word feral has its origins in the Latin fera, or wild animal, or ferus which is simply translated as wild. Funnily enough, fairly recent (2003) adjustments to taxonomical nomenclature of horses have made space for the extinct wild ancestor of Equus caballus, the domestic horse. These previously unclassified ancestors were named Equus ferus and proponents of this line of thinking suggest that the nomenclature of domestic horses should thus be: Equus ferus caballus.

Furthermore modern dictionaries like “American Heritage® Dictionary of the English Language, Fourth Edition 2000”, propose in most cases two distinct definitions for feral, as follows:  

1) Existing in a wild or untamed state

2) Having returned to an untamed state from domestication.

Recently however, some scientists propose reconsidering the use of the term “feral” for designating free ranging horses on at least two grounds. The first is the theory or belief of native indigenous non-domestic descent, while the second is a plea against its usage based on likely negative consequences as in this quote from Kirkpatrick & Fazio:

“Customarily, such wild horses that survive today are designated “feral” and regarded as intrusive, exotic animals, unlike the native horses that died out at the end of the Pleistocene. But as E. caballus, they are not so alien after all. The fact that horses were domesticated before they were reintroduced matters little from a biological viewpoint. Indeed, domestication altered them little, as we can see by how quickly horses revert to ancient behavioral patterns in the wild.” (Kirkpatrick & Fazio 2008)

The above statement may be true, false or partly both, but that does not change the fact that Kirkpatrick & Fazio are aware of the domestic ancestry of horses. They however claim that domestication, which truly is a blink of the eye in as much as evolutionary timescales are concerned, has altered horses little. The topic of little genetic alteration through domestication will surely be a topic for others to refute if they wish to, but for the purpose of this article let us concentrate on the issue of having descended from domestic stock as the reason behind the term feral.

Ross McPhee, Curator of Vertebrate Zoology at the American Museum of Natural History, recently defended the “nativeness” of Equus caballus to the North American continent with an apt and eloquent argument. In a nutshell: the bulk of horse evolution occurred in North America up to a species very similar to Equus caballus, and these crossed over to Eurasia and South America before going extinct in Northern America, later to be re-introduced by colonizers to the same continent from which they once came. (Read it here: MANAGED TO EXTINCTION? )

Once again, it seems there is no dispute that the extant wild horses of North America have indeed descended from domestic stock. Whether one should reconsider horse’s native, indigenous etc… or not, has no bearing on whether they are feral =>from domestic descent.

In basic terms, the following description from the American Museum of Natural History sums it up pretty well:

“The so-called “wild” horses that abound in Australia and North America are actually feral. A domestic animal becomes “feral” simply by fending for itself when left in the wild, without being helped or managed by humans in any way. If it finds others of its own species, reproduces, and the offspring also fend for themselves in the wild, the result is a feral population.” ( http://www.amnh.org )


Some criticism on the matter of feral vs. wild

The matter of feral versus wild has inundated the social media. The main marketing strategy for this seems to be “you’re either with us or against us”, pushing people to think that those that utilize one term are “good and intelligent” while those that use the other are “misinformed, conspiring or misguided”.


It saddens me to think that people who share a passion for horses can be so self-centered and can’t see past the tips of their noses. Social media is an easy way to spread gospel and biased unsubstantiated claims about the work of others, and it’s apparently free. I do understand that much of the gospel is spewed forth for the best of intentions, but good intentions are biased by necessity. I refrain from posting examples of this carefree slander, so as not to fuel bad taste.

Controversy, what controversy? There really is none in the usage or definition of the term “feral”. Free ranging horses, wherever they may be in the world, are either descended from domestic horses, or they are not.

In my opinion, debates on topics like these only distract people from many other aspects more important to the preservation and conservation of free-ranging, feral, or wild horses such as further behavioral and ecological field studies that are likely to result in more viable and stable management schemes.

A plea for protection and conservation

Whether we label free ranging, wild or feral horses in one way or another, antiquated and biased population maintenance practices still abound.

In many parts of the world there are heated debates as to whether horses, the descendants of those that once carried man into the modern ages in more ways than one, should be left to roam freely or should be controlled strictly and considered an invasive pest.

The word we use to describe a population that is when once was not, or even, was and has not been for some time, will make no difference to our need, or greed for expansion. Many populations of free-ranging horses have been reported to cause havoc to local flora and fauna in their ranges. Some people may consider this unacceptable others just unavoidable given the circumstance.

Damn, that’s a very difficult question to answer in many respects. We have already interfered with most ecosystems in the world, either directly or indirectly. Our encroachment of greener pastures for whatever our interest, has pushed horses into marginal lands across the globe.

Now our encroachment is taking that away from the horses too!

In my opinion science is not likely to sort out our moral, ethical or political beliefs or battles, but it can give us the criteria to freely decide for ourselves.


“The coming generations will have good reason to call us unfaithful stewards if when we are gone there are no longer little horses on the Exmoor hills.”  Mary Etherington (1947)

I would like to extend Mary Hetherington’s quote to include the majority of the free ranging feral horse populations in the world that are having a bumpy ride on earth because some species are considered worthy of protection while others are not.


Further articles regarding the feral-wild-native-indigenous dichotomy:

Are the wild horses of the American west native?

The Surprising History of America’s Wild Horses


The Aboriginal North American Horse

The genomic signature of dog domestication reveals adaptation to a starch-rich diet (full text paper)

4 thoughts on “Feral horses

  1. Reblogged this on WILD HORSE HUB CENTRAL and commented:
    From our friends at EQUILIBRE Gaia’ (I did look up Gaia and it was a surprise, but not one that changed the way I listen to the wisdom of Victor Ros, Director. Thank you for what you do, as always, WHHC.

    • Thanks for reblogging this post. Curious to see what you found when you looked up Gaia. Just to clarify, our Center is in the local Spanish town of Santa Perpetua de Gaia, and Gaia is the name of the river that crosses through our land. So the name Gaia after Equilibre is only a geographic distinction, and not a way of “seeing” the world. Best always, Vic

  2. Some years ago when I was investigating the New Zealand Kaimanawa horses an interesting sentence stuck in my mind, it was from the Department of Conservation pages I think, a horse is wild when its survival does not depend on man for feed.
    It’s a nice distinction wild or free and fed.
    We talk about feral horses having domesticated ancestors but in reality all domesticated horses had wild horse ancestors further back…

    • Thanks for sharing Tamlyn, and absolutely agree. The names we use to label free roaming, wild or feral horses should not be equated to better or worse, vermin or wildlife, but instead afford limitations by highlighting important variables to consider in our generalizations of their behavior and relationship with the environment in which they inhabit.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s