Center for Biological Diversity

For Immediate Release, April 12, 2023


Robin Silver, (602) 799-3275,

Lawsuit Launched Over Massive Habitat Reduction for Endangered Snakes in Arizona, New Mexico

TUCSON, Ariz.— The Center for Biological Diversity filed a formal notice today of its intent to sue the U.S. Fish and Wildlife Service for reducing critical habitat for two endangered snakes by more than 90% from what it originally proposed to protect the animals.

In 2021 the Service reduced protection to 447 stream miles in the Southwest as critical habitat for the narrow-headed garter snake and 217 stream miles of critical habitat for the northern Mexican garter snake. That amounted to roughly 44,000 protected acres in Arizona and New Mexico. However, the agency had drastically reduced the amount of critical habitat from what it originally proposed in July 2013 — by 93% from the original 421,423 acres for the northern Mexican garter snake and a 91% reduction from the 210,289 acres proposed for the narrow-headed garter snake.

“Federal biologists are abdicating their duty to protect these species by giving them enough habitat to survive and recover,” said Robin Silver, a cofounder of the Center. “It’s disappointing to see them buckle under pressure from other interests, including ranchers and state and federal agencies, when so many species face extinction. Endangered species like these rare aquatic snakes will disappear forever if we don’t protect the places they need to live.”

The agency ignored snake experts and its own scientists before shrinking the snakes’ protected habitat. Among other things, it excluded hundreds of thousands of acres of ephemeral streams — despite noting in its own proposed rule that both the northern Mexican and narrow-headed garter snakes “rely on terrestrial habitat for thermoregulation, gestation, shelter, protection from predators, immigration, emigration, and brumation.”

Arizona and New Mexico waterways now protected for the snakes under the Endangered Species Act include 46 miles of the Gila River, 71 miles of the San Francisco River, 52 miles of the Blue River, 20 miles of the Tularosa River and 27 miles of the Verde River. Yet when it was considering the snakes for federal protection in 2013, the Service originally proposed to safeguard 1,380 stream miles for the narrow-headed garter snake.

Both garter snake species were listed as threatened in 2014. Both are disappearing as Southwestern streams continue to be degraded by livestock grazing and mining, upended by invasive species, drained for agriculture and suburban sprawl, and shrinking with climate change-induced drought.

The Center first submitted a petition to list both garter snakes under the Endangered Species Act in 2003 and had to file multiple lawsuits before the Service listed the snakes in 2014. At the time the agency had proposed protecting more than 420,000 acres of critical habitat for them.

“Protecting rivers that disappearing animals rely on benefits snakes, fish, birds, amphibians and mammals, including people,” said Silver. “It’s taken way too long to protect these snakes, but slashing their habitat is a blow they will not survive. We have to protect and restore these rivers and ephemeral waters to keep these snakes swimming and thriving.”

Narrow-headed garter snake. Photo credit: Pierson Hill. Image is available for media use.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.7 million members and online activists dedicated to the protection of endangered species and wild places.

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