How an Introduced Species Exploded to 20,000 and Is Now Threatening Texas Wildlife
The real story behind one of Texas’ biggest wildlife headaches starts with a decision the state made on purpose.
In 1957, the Texas Parks and Wildlife Department released 31 aoudad — also known as Barbary sheep — into the Texas Panhandle. The goal was straightforward: give hunters more to shoot. An additional 40 animals were released the following year, bringing the total to 71.
That population of 71 has since grown to more than 20,000, according to TPWD. And the species those 20,000 are now pushing out? Native desert bighorn sheep, which the state also manages and protects.
The aoudad didn’t stay put in the Panhandle. They spread into West Texas, including the Trans-Pecos region, where they now share habitat with desert bighorn sheep.
TPWD surveys in 2025 recorded approximately 730 desert bighorn sheep statewide. Set that against the 20,000-plus aoudad and the imbalance is obvious.
Wildlife officials say aoudad reproduce far more quickly, often producing twins twice a year. Bighorn sheep typically have one offspring annually. On top of that, aoudad compete directly with native sheep for forage — so the faster-breeding invasive species is also eating the native species’ food.
Competition alone would be concerning. But the disease angle is what turned this into a crisis.
In 2019, desert bighorn sheep in West Texas were hit by a pneumonia outbreak linked to the pathogen Mycoplasma ovipneumoniae. Researchers identified aoudad as potential carriers of the disease — often without showing symptoms themselves.
The fallout was severe. According to TPWD data, the desert bighorn population dropped from about 1,500 animals in 2019 to fewer than 500 by 2024 following the outbreak. That’s roughly two-thirds of the population gone in five years.
Now a separate disease is spreading among aoudad in West Texas. Infectious keratoconjunctivitis, commonly known as pinkeye, has been documented across a wide area. TPWD reported, “Since December [2025], approximately 25 Aoudad showing severe clinical characteristics (e.g., blindness) in one or both eyes have been documented across 30 miles.”
TPWD described the disease as “a highly contagious eye infection that can be a common disease in livestock. IKC has also been described in many wildlife species. It rarely affects just one animal, but spreads throughout a herd.” The agency added it “can be spread by flies, dust, and other exposed environmental vectors. In wildlife populations there is no available treatment and the disease naturally runs its course through the herd.”
So far, TPWD has not documented IKC cases in desert bighorn sheep but is monitoring closely due to potential risk. Given what happened with the 2019 pneumonia outbreak — where aoudad carried the pathogen without visible illness — the concern is that pinkeye could make the jump as well.
To manage the growing aoudad population, Texas enacted Senate Bill 1245, which took effect on Sept. 1, 2025. The law allows aerial hunting of aoudad from helicopters on private land.
That matters because of a key fact about Texas: more than 93% of land in the state is privately owned. Aoudad are classified as an exotic species and have no closed season or bag limit on private property, meaning landowners can now hunt them from the air year-round with no limit on how many they take.
TPWD is also managing populations through public land hunts and working with research partners, including Texas A&M University and Borderlands Research Institute, to study disease transmission and population control.
This article was created by content specialists using various tools, including AI.
