Bighorn Sheep Near the North Entrance of Yellowstone National Park are Dying from Pneumonia

Bighorn sheep near the northern entrance of Yellowstone National Park are dying from pneumonia. Pneumonia outbreaks in bighorn sheep are often associated with contact with domestic sheep or goats which carry many pathogens that cause pneumonia in bighorn sheep but do not affect domestic sheep or goats.

According to a press release by Montana FWP, in the past two weeks, FWP staff members have collected ten dead bighorn sheep – a mix of rams, lambs, and one adult ewe.

The Wildlife News readers will recall that a bighorn sheep was observed last year in the same pasture as several domestic sheep owned by a resident of Gardiner, Montana. It is unknown whether bighorn sheep had any contact with these domestic sheep.

Bighorn Sheep near north entrance of Yellowstone National Park  © Ken Cole
Bighorn Sheep near north entrance of Yellowstone National Park © Ken Cole

This herd of bighorn sheep is highly visible to visitors of Yellowstone National Park. The outbreak comes during the bighorn sheep rutting season when rams often travel long distances in search of mates. Because bighorn sheep and domestic sheep are closely related bighorn sheep rams have an attraction to domestic sheep and are likely to intermingle during the rut.

Several pathogens carried by domestic sheep and goats have been linked to deadly pneumonia outbreaks in bighorn sheep. It is likely that it may take more than one of the pathogens to result in an outbreak but at least one of the pathogens has been unequivocally linked in laboratory testing to cause pneumonia and death of bighorn sheep.

All age die-offs of bighorn sheep have been known to result in the deaths of up to 90% of the herd and the effects of the outbreaks often plague the herds for a decade or more by killing young lambs that have no immunity to the pathogens. There is no known vaccination or cure for these pathogens and any resistance that an individual bighorn sheep may develop is not passed to their offspring.

In the winter of 2009-2010 The Wildlife News reported on several pneumonia outbreaks that killed hundreds of bighorn sheep in several states.

The Wildlife News has advocated in the past for zoning laws that would restrict domestic sheep use in areas where bighorn sheep occur. We continue to advocate for this position.


  1. larry thorngren Avatar

    When I saw bighorn ewes and lambs coughing and sneezing across the river from Corwin Springs last year, I went up to the Yellowstone research building in Mammoth Hot Springs and talked to the person who told me he was in charge of research for Yellowstone Bighorns. I did not write his name down and cannot recall it.
    However, when I said that the bighorns were in danger from the domestic sheep down toward Corwin Springs and that something needed to be done about it, he blew me off and said “they are on private property and the rancher can do a the pleases”. He essentially told me that he wasn’t going to try to do anything about it and it was none of the park’s business. He seemed irritated that I thought something should be done.

    1. rork Avatar

      Maybe he was irritated cause you, for unknown reasons, thought something COULD be done by this person.

  2. Ed Loosli Avatar
    Ed Loosli

    from Montana Fish Wildlife & Parks:
    “FWP, within its scope of authority, works to ensure separation of domestic and wild sheep. This includes the lethal removal of any wild sheep known to have been in direct contact with a domestic sheep.”

    With all due respect: Why doesn’t Montana FWP include, lethal removal of any domestic sheep known to have been in direct contact with wild sheep, instead of the other way around?? Why is it always the wildlife that has to take the hit from being near domestic livestock??

    1. Frenchy's Meadow Avatar
      Frenchy’s Meadow

      FWP needs to work something out with the domestic sheep owner Mr. Hoppe on this issue.

      1. skyrim Avatar

        “work something out”……..
        A damn good start would be to stop frequenting his tourism business enterprises.

        1. Joanne Favazza Avatar
          Joanne Favazza

          Hoppe is a scourge to wildlife. He shot and killed a collared park wolf a couple of years ago that he lured with sheep carcasses.

      2. Brett Haverstick Avatar
        Brett Haverstick

        Hoppe is also public enemy number one for grey wolves in the Gardiner area.

    2. Mtnman Avatar

      So this is coming down to making the whole state a wildlife management area that the rich out of town or out of state people can come view without having to live with the consequences of their legislation!! There is ways to vaccinate however the cost is greater than the means and like any vaccination not a sure preventative,but they don’t tell the general public that. One solution is creating a more inviting winter range away from domestic livestock???? My family ranched in Cinnabar Basin for fifty years ending in the mid 1990’s and and one time owned Corwin Springs . That wild sheep herd wintered and summered with their livestock without any problems other than normal diseases and natural causes predators etc., by the way this includes pneumonia. Current methods by the fwp have long been proven to work Montana boasts a large sheep herd that contains the next B&C world record , hard work by the fwp and hunting conservationist groups has made this so. While an outbreak is scary and can potentially have terrible consequences they do happen with or without contact . The pasturella pathogen does occur naturally and is vaccinated for in domestic livestock however this does not prevent all cases. The sheep may or may not have been the catalyst but was not the sole cause number one healthy non-stressed animals usually don’t contract diseases immune or not . I am an avid wild sheep enthusiast and professional guide in the greater Yellowstone. Asaroka-Beartooth in Mt. And the Thorofare region in wy. I spend six to eight months observing all the wild life in the whole greater Yellowstone and the remainder running livestock in the region. The single most catalyst for weaker disease prone animals is an overpopulation of predators and Bison in the region. The over population of bison and predators have driven the elk herds into sheep habitat and out of the valleys and timber thus putting pressure on the bighorn . Also more apex predators means the cougar targets more sheep because the wolf is eating more deer, adding to the stress the golden eagle puts on them. Any pneumonia outbreak in wild sheep is tragic and is cause for immediate attention to assert it don’t spread. These protocols already exist within the fwp and I’m sure they are working hard to implement one of them. Thank you for your time.

      1. Ken Cole Avatar

        There is NOT a vaccine that has been developed for either domestic sheep or bighorn sheep against the pathogens causing pneumonia in bighorn sheep. Virtually every domestic sheep carries these pathogens.

        You also say:

        Current methods by the fwp have long been proven to work Montana boasts a large sheep herd that contains the next B&C world record , hard work by the fwp and hunting conservationist groups has made this so.

        How do explain the mass die-off that killed nearly 700 bighorn sheep in the winter of 2009-2010? This is just the beginning of this outbreak. Stay tuned, I’m sure hundreds more sheep will die in this one too. FWP is powerless to do anything to stop it.

        The only solution would have been to keep domestic sheep out of the Gardiner but nobody, not FWP, not the NPS, not the U.S. Forest Service, not Park County did a gawd-damned thing to prevent this. This is on them and the certain individual, who I believe, saw the money that CUT got and wanted his/her share of the money too.

        1. Elk375 Avatar

          Ken where did the mass die of 700 Big Horn sheep occur in the winter of 2009-2010? I know that there was several large mass die offs of sheep.

  3. Ida Lupines Avatar
    Ida Lupines

    Very sad. This sounds like a very cruel man. Isn’t this awful that people freak completely out over brucellosis, the latest E. granulosus (nevermind the fact that our domesticated pets and livestock, that number in the millions in this country carry tapeworms and other diseases too), but yet completely ignore something like this?

  4. Anita Chittenden Avatar
    Anita Chittenden

    Why are domestic sheep still allowed to graze on private or public lands..where Native Bighorn Sheep are near by?..This is in CA. but it talks about the domestic sheep being a danger of the bighorn sheep giving them Pneumonia..Why can’t Montana do the same..How very sad this is and could have maybe been avoided..again Native Wildlife paying with their lives!

    [PDF]Domestic sheep, bighorn sheep, and respiratory disease: a …

  5. jable Avatar

    That “Gardiner resident” had his sheep back in that pasture this year.

  6. John Avatar

    I agree with some of the posts here. Domestic sheep should not be anywhere near wild life and same with cattle. Both are imports which sicken our natural wildlife but always it is the ranchers who cry their tears of ‘foul’. Same here in Washington state. They cry and cry and nature suffers. Both states are backward run via the rancher mentality of not caring. Totally sad.

    1. rork Avatar

      “not be anywhere near wildlife” would mean no cows or sheep at all in many states. We might want to try for something a bit less drastic, that has some chance of actually happening.

  7. jerry collins Avatar
    jerry collins

    An obvious need for more wolves,especially for the domestic sheep in the area. With the FWS killing off the Bison, and everything else with fins fur and feathers, the west will soon be over run with cows.

  8. rork Avatar

    “It is likely that it may take more than one of the pathogens to result in an outbreak” was a bit puzzling.

    1. Ken Cole Avatar

      Most of the current science indicates that it may take the presence of one of the many pathogens implicated in bighorn sheep pneumonia, Mycoplasma ovipneumoniae, to pave the way, in a sense, for other pathogens such as Mannheimia haemolytica to cause full blown pneumonia. At this point, the actual mechanisms haven’t been fully worked out but there is no doubt that contact between the two species results in severe consequences for bighorn sheep.

      1. rork Avatar

        Thanks. Should have studied harder on my own, but am lazy sometimes.

        1. Nancy Avatar

          Excellent link posted by Rod below on the subject.

  9. Logan Avatar

    I agree with everyones comments, all domestic sheep need to be removed from areas that support Bighorn populations. As bighorns expand their range, domestic sheep should be removed ahead of them. We can get more sheep if we need them but Bighorns don’t come so easily.

    On a side note, the article says that pneumonia can be transmitted to Bighorns by domestic sheep and goats. Noone will dispute the fact that sheep can spread disease but does anyone have any documentation that goats can pass on pneumonia? What about alpacas or llamas? I ask because I have been looking at the possibility of using pack goats or llamas on long distance backpacking trips but I certainly don’t want to endanger bighorns in the areas I plan on visiting.

    1. Mark L Avatar
      Mark L

      Here’s one:
      “While the body of literature linking disease transmission from domestic goats (Capra aegagrus hircus) to bighorn sheep is not as extensive as that of domestic sheep, nonetheless, it does exist. As in domestic and bighorn sheep, strains of Mannheima haemolytica are the organisms most frequently isolated from the lungs of pneumonic domestic goats. Mannheima haemolytica A1 is infrequently isolated from the upper respiratory tract of healthy bighorn sheep, and is thought to act as an opportunistic invader in much the same way as other strains of Pasteurella spp. Mannheima haemolytica A2 has been found in the upper respiratory tract of healthy domestic sheep and goats, but has not been isolated from healthy wild sheep (Garde et al. 2005). It is thought that bighorn sheep are infected with M. haemolytica A2 through contact with domestic sheep or goats (Foreyt et al. 1996, Martin et al. 1996, Schommer and Woolever 2001). This bacteria has the potential to act as a primary pathogen in bighorn sheep, resulting in all age die-offs (Garde et al. 2005). In addition pasteurella spp. were isolated from feral goats and bighorn sheep in the Hells Canyon National Recreation Area. Although the direction of transmission could not be established, evidence suggests transmission of strains from goats to bighorn sheep (Rudolph et al. 2003, Foreyt et al. 2009)”


      Risk Analysis of Disease Transmission between Domestic Sheep and Goats and Rocky Mountain Bighorn Sheep

      …sorry, gotta be an easier way to show the usda site, but best I could find at the moment. Note some pathogens were isolated from feral goats, which wouldn’t be your case with pack goats (I like ’em too, BTW).

  10. Ken Watts Avatar
    Ken Watts

    Can the Bighorn Sheep be inoculated?

    1. Ken Cole Avatar

      No. The only effective way to keep bighorn sheep from contracting pneumonia from domestic sheep is keep them very far apart.

  11. Gary Humbard Avatar
    Gary Humbard

    Someone mentioned Bill Hoppe as the landowner who has the domestic sheep, the same guy who has had numerous conflicts with bison. Since we have private property rights in this country, one solution would be for a CO like Defenders try to sign a contract where Defenders would pay him for the permanent removal of domestic sheep from his property. If the sheep are on public land then a group like The Conservation Fund could purchase the grazing permit and permanently remove the domestic sheep.

    Whether people like it or not, grazing permits provide a economic value to the permittee and government agency and there needs to be economic incentives to remove the livestock when conflicts arise. That is why I financially support The Conservation Fund.

    1. tim zaspel Avatar
      tim zaspel

      “Whether people like it or not, grazing permits provide a economic value to the permittee and government agency”

      Oh really?

      “Experts estimate that direct and indirect costs of the federal grazing program may add up to as much as a $1 billion loss each year for taxpayers.”

      1. Nancy Avatar

        “Experts estimate that direct and indirect costs of the federal grazing program may add up to as much as a $1 billion loss each year for taxpayers.”

        Tim zaspel, pretty sure Gary is aware of that fact (given his work history) but as of now, there are no alternatives/incentives on the horizon, to do anything about the situation of what it cost taxpayers.

        The definition of the word permit means to “allow” and many of these permits are like gold to livestock grazers and, treated that way when ranches are bought and sold.
        Please, anyone, chime in if I’ve misunderstood that concept of how western lands (and wildlife too) continue to be manipulated, tossed around by a few, with heavy handed $$ influence back east.

        A good read:

        1. timz Avatar

          “Tim zaspel, pretty sure Gary is aware of that fact”

          Than maybe he could explain where the economic value is when it comes at such a huge cost.

          1. Gary Humbard Avatar
            Gary Humbard

            timz, for each AUM, the agency receives money albeit at a very low rate. If no livestock were permitted on the grazing allotment, the agency would not receive any money from the permittee, but would also not incur costs associated with the permit. Everyone knows the ultimate winner is the permittee, but when I read “livestock should be removed from public lands”, this is not reality. Conservation organizations who purchase perpetual grazing permits from willing permittees is a proven way to resolve issues such as described in this post.

            1. Ed Loosli Avatar
              Ed Loosli

              Gary Humbard:
              As far as I know, the BLM does not allow grazing leases to be bought out by conservationists. If a lease is bought from a rancher, they also MUST put cattle or sheep on the allotment and at the numbers called for by the BLM. Exceptions are few, if any.

              1. Gary Humbard Avatar
                Gary Humbard

                Ed Loosli, there are perpetual BLM and FS grazing leases being purchased from willing ranchers from COs such as The Conservation Fund without the requirement of having any livestock on the allotment. I talked with the Arizona coordinator of the “Fund” and he explained their strategy and accomplishments. Some leases come with caveats that require that livestock remain, however, many do not and when wildlife conflicts arise those are the ones they target for purchase.


    2. Ralph Maughan Avatar
      Ralph Maughan

      Hoppe has been well known in the area for years as an anti-wolf militant.

      Gary Humbard, I believe that public grazing permits are not an issue in this instance but I could be wrong.

      1. Ken Cole Avatar

        Hoppe’s sheep have been seen on the private pasture just downstream and across the river from the Yellowstone National Park boundary just recently.

  12. Rod Coronado Avatar

    chlamydia bacteria has also been transmitted to bighorn from goats and causes blinding which resulted in numerous bighorn deaths in Arizona. It’s not breaking science that domestic livestock infect native wildlife with fatal disease. It’s blatantly ignored in favor of pseudo-science that promotes the fear that native wildlife like bison, transmit disease to livestock. The Gardiner rancher in question grazes sheep literally on the north bank of the Yellowstone River while on the south bank within the park, bighorn sheep congregate. Just north of town another rancher grazes sheep without a fence directly on the river.
    FWP spokespeople told me this Fall that its the fault of the National Park Service (and people like your readers)to think that the rest of Montana should be treated like a national park. Their position is that wildlife has to cope with multi-use policies the moment the cross that park boundary. Also, the domestic sheep grazing in question is all on private lands and is hobby farming at best.

    1. Elk375 Avatar


      I am truly a bit confused. The Yellowstone River Runs north and south from Gardiner to Livingston how can there be a north and south bank. There is a east and west bank.

      1. Yvette Avatar

        Elk375, I bet you are confused. Streams meander, so even if a stream/river flows in a general north/south direction there will be reaches that will flow east/west. So the way we determine and notate banks is to use the terminology, left bank/right bank. When facing downstream the left bank is on your left; if facing upstream the left bank is on your right.

        1. Ken Cole Avatar

          That depends on whether you are fisheries biologist or a hydrologist.

  13. Elk375 Avatar

    If one goes to The Wild Sheep Foundation Facebook page there are pictures of Hoppe’s sheep with a ram. For those of you who do not like hunting do not scroll down any farther.


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