Bison in Texas: Native or Exotic?

When one thinks of the old west, the mind’s eye may see cowboys and Indians in a gunfight, or maybe the transcontinental railroad cutting across the country, or a prospector panning for gold… but I think of bison. The great beasts of the plains, once millions strong in herds a mile wide that continued onward as steady as time, and nearly lost to the hands of greed and negligence. The dismal history of bison prefaced, what is often considered, one of the great conservation successes and led to bison becoming the national mammal of United States of America. But were those conservation efforts to save this iconic species actually successful– it depends on the perspective and definition of success.

North American plains bison (Bison bison) went through an extreme genetic bottleneck when the population was decimated by indiscriminate commercial hunting and disease epidemics introduced by domesticated cattle. The remaining bison were protected, and the species recovered before physical extinction, but random cross-breeding and intentional efforts to hybridize cattle and bison by ranchers and wildlife managers became rampant. Cattle ranchers were hybridizing bison and cattle to produce a “beefalo” that was heartier and more durable than cattle but with a higher quality beef than bison. When these hybrids bred back to bison, they became visibly indistinguishable from pure bison¹. As a result, wildlife managers also contributed to spread hybridized bison, often unintentionally by integrating hybridized bison into pure bison herds but occasionally intentionally to bolster bison genetics against diseases without changing the physical appearance. After generations of visually indistinguishable hybrid bison contributing to the gene pool of the population, it was thought there were only a few genetically pure herds remaining such as the Yellowstone, Custer, Wind Cave, and Castle Rock (Vermejo) Herds. Unfortunately, with the use of advanced genetic sequencing techniques, a recent study from Texas A&M University indicated that even the genetically pure herds are in fact infested with cattle genes³. This essentially means that pure North American plains bison are genetically extinct, including those bison in the Texas state bison herd at the Caprock Canyons State Park. So was the conservation effort to save bison a success? Genetically, no. Ecologically, yes, because although the remaining bison are not 100% pure, they appear as if they were pure and are still on the landscape fulfilling the ecological role. So, if we, as wildlife managers, consider the saving of bison a success, do we consider them native wildlife or exotic livestock?

At a national level, bison are considered a wildlife resource that the United States Department of the Interior actively works to restore on Native American reservation and national forest/park land⁵. At the state level, only six states (Alaska, Arizona, Montana, Utah, South Dakota, and Wyoming²) recognize bison as a game animal with regulated seasons and bag limits. In Texas, however, similar to many of the remaining 44 states, bison are considered livestock, regulated by the states’ livestock health agencies (i.e.- Texas Animal Health Commission) and propagated by private ranches for meat, fiber, hunting, or other purposes³. Bison, as “exotic livestock” in Texas, are not subject to hunting regulatory seasons, methods of take, or bag limits. The harvest of bison is legally equivalent to butchering a domestic livestock animal (cow, sheep, goat, hog, etc.), and the live sale and/or movement of bison is regulated similarly to domestic livestock, albeit with less disease surveillance (i.e.- trichomoniasis testing exemption). Despite these considerations, there is a heritage wild bison herd managed at the Caprock Canyons State Park in Briscoe County, Texas– the Official State Bison Herd of Texas.

The animals belonging to the Texas State Bison herd are descendants of the last wild Texas bison known to survive, which were rescued, adopted, and raised by Molly and Charles Goodnight in the late 1870’s. The handful of young bison were the genesis of the private Goodnight Bison Herd on the Goodnight’s JA Ranch in Armstrong County. Decades later, the bison herd was donated by the JA Ranch to the state of Texas and moved to the Caprock Canyons State Park in 1997 to become what is now the Texas State Bison Herd⁴. Occasionally these animals are rounded up for genetic culling and general health checks to keep the herd as healthy and genetically robust as possible⁴, but for the most part, the herd is managed as a wildlife resource at the park.

All this circles back to show the answer to the question, “Are bison native or exotic to Texas?”, is complicated and not-at-all straight-forward. From a cultural perspective, bison are the National Mammal of the United States and a religious symbol to many Native American cultures. From a historical perspective, the bison range included Texas and bison were never completely physically exterminated from the landscape. From a genetic perspective, pure American plains bison are likely genetically extinct. And from a regulatory perspective, bison are exotic hoof-stock in Texas.