I'm working on a setting where one of the large continents is similar to North America before the arrival of humans, including a biome containing the three large grazing ungulate species: aurochs, bison, horses. I'm trying to figure out exactly what their ranges will be, and in particular, how they relate to each other.

All three are stereotypically animals of the prairies, but bison at least seemed to actually be able to live in quite forested regions. There is an account here of what seems to have been quite a substantial population of bison in Louisiana, which is nowhere near the prairies, and at first glance, entirely forested: https://heartoflouisiana.com/last-buffalo-in-louisiana/

I'm not quite sure how it is possible for a grazer to live in a forest, but there is a variety of bison called the wood bison https://en.wikipedia.org/wiki/Wood_bison confirming it is possible. Perhaps primordial forests are patchier, possessed of more meadows or at least margins of grass, than one might think?

Is this also true of aurochs and horses? Or put another way, if you make your way from forest toward prairie, would you be equally likely to encounter all three species at any given time? Or would you have a scenario where you could encounter bison in the forest, but would need to travel another few hundred miles up the Mississippi, say, before reaching prairies and encountering horses?

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    $\begingroup$ The Auroch at least is easy. They were dwellers of floodplain forests and marshes. Odds are that a Horse and an Auroch would never lay eyes on each other. $\endgroup$
    – PcMan
    Oct 5, 2021 at 7:24
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    $\begingroup$ TIL: aurochs - depending of geography, not a very often bit of general culture (which is to say it would worth a link from the question to wikipedia). Do you mind to put it in or should I? $\endgroup$ Oct 5, 2021 at 7:58
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    $\begingroup$ Have you checked this link? It has a pretty comprehensive analysis on feeding ranges - including the split between browsers, intermediate feeders and grazers $\endgroup$ Oct 5, 2021 at 7:59
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    $\begingroup$ The aurochs could live in the steppe (= the Eurasian correspondent to American prairies, sort of), but it most clearly did not have to. There were aurochses all over Europe, and the Eurasian steppe is limited to the southern part of the really eastern part of Europe, north and east of the Black Sea. The aurochses which survived into historical times, for example in Poland and Moldavia, lived in forested areas; maybe not densely forested, but definitely not the steppe. $\endgroup$
    – AlexP
    Oct 5, 2021 at 8:36
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    $\begingroup$ Looking into this a little I did not find that there were aurochs in North America. Is your fictional world supposed to be North America or can it be patterned on someplace where these 3 did coexist? $\endgroup$
    – Willk
    Oct 5, 2021 at 14:02

1 Answer 1


Here is a proposal.

  1. Aurochs are wetland specialists. Your auroch herds will be along rivers and in wetlands / flooded areas. You can pattern them on the existing niche for water buffalo. In temperate areas they might make seasonal migrations.

  2. Bison are browser / grazers. They are versatile and subpopulations might specialize in one ecosystem type or another. Large herds will roam the grasslands as the American bison did. Smaller groups would live in open forest or edge ecosystems as European bison did in historic times. There are places where the bison and auroch overlap and even interbreed.

  3. Horse groups are everywhere. Horses can get by in more marginal territories but will exist in rich territories also. They live from the desert all the way to subalpine areas with regional adaptations for these subpopulations or even subspecies. Small groups of horses or small stallion herds can be found at higher altitudes than the bovids, and in drier places where browse would not support herds of bovids. Occasionally horses will join mixed herds with bison as one can see with zebra / wildebeest mixed herds in Africa - the bison benefit from the keener senses of the horses and the horses benefit from the offensive capabilities of the bison.

  4. Yaks. Did you mention yaks? I guess I dreamed that. Can you have yaks too please?

  • $\begingroup$ Okay, you had me right up to yaks. ;-) $\endgroup$
    – DWKraus
    Oct 5, 2021 at 20:37
  • $\begingroup$ Upvoted for the yaks. The question should have mentioned yaks. Thank you for uphelding these beatiful hairy animals. $\endgroup$
    – AlexP
    Oct 7, 2021 at 20:09

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