We, the undersigned organizations, scientists, and members of the public, write to express deep concern about current federal management decisions that are driving the genetically unique, geographically isolated Carter wild horses toward functional extinction.
“Functional extinction” describes a point where a population has been reduced so severely that it can no longer play its natural role in the ecosystem or sustain itself as a viable, reproducing group without suffering progressive loss of fitness due to inbreeding and genetic drift. In other words, animals may exist on paper, but the population is no longer healthy, self-sustaining, or capable of long‑term survival. The Carter herd identity will be irrevocably lost to history.
For wild horses, conservation biologists and federal experts have long recognized that herds need on the order of 150–200 animals of breeding age to maintain adequate genetic diversity and avoid inbreeding depression over time. By contrast, current plans for the isolated Carter herd would reduce this population to just 25 animals and then layer on fertility control, while more than 280,000 acres of land that were originally designated for wild horse use have been effectively stripped away to prioritize commercial livestock, without adequate environmental analysis or transparent justification.
This combination—drastic numerical reduction, ongoing fertility suppression, geographic isolation, and loss of designated range—meets the very conditions that define functional extinction. A herd of 25 closely related horses simply cannot maintain the genetic diversity and demographic resilience needed to withstand disease, drought, fire, and a changing climate. The result is a managed slide toward disappearance, not lawful, science‑based stewardship.
The Carter wild horses are not only part of our national heritage; they also represent a distinct genetic and cultural resource that cannot be recreated once lost. Federal law directs that wild free‑roaming horses and their ranges be protected as an integral part of the public lands on which they live, not reduced to a token remnant while livestock interests are elevated above statutory designations. Management choices that knowingly render this herd functionally extinct undermine that mandate and erode public trust in our institutions.
Accordingly, we respectfully urge you to:
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Ensure that management of the Carter herd is aligned with modern conservation genetics by setting population objectives that are large enough—and connected enough—to maintain long‑term genetic viability, rather than arbitrarily reducing the herd to 25 animals under fertility control.
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Restore and honor the full acreage originally designated for wild horse use in the Carter complex, and require robust environmental review and public disclosure before any changes to those designations or to the balance between wild horses and commercial livestock.
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Exercise rigorous oversight to confirm that federal wild horse policies are grounded in best available science and the intent of Congress, instead of being driven by pressure to maximize private livestock use of public lands.
Wild Horse Education and Carter Reservoir Mustangs, Inc. have brought these issues before the federal courts, challenging the legal and scientific adequacy of the current management framework for the Carter, Buckhorn, and Coppersmith areas. The depth and breadth of public concern reflected in this letter underscores that what happens to the Carter wild horses is not a niche issue; it is a test of whether wild horse and burro protections on our public lands remain meaningful.
We ask you to stand on the side of science, law, and future generations by rejecting management actions that would render the Carter herd functionally extinct, and by supporting a future that keeps these wild horses truly wild, viable, and present on the landscape.
Sincerely,