Center for Biological Diversity

For Immediate Release, August 21, 2018

Contact: Jenny Loda, (510) 844-7100 x 336,

Lawsuit Launched to Protect Critical Habitat for Two Threatened Snakes in Arizona, New Mexico

PHOENIX— The Center for Biological Diversity today filed a formal notice of intent to sue the U.S. Fish and Wildlife Service for failing to designate critical habitat for the northern Mexican garter snake and narrow-headed garter snake.

Threatened by nonnative species and the loss and degradation of their riverside habitats, these aquatic garter snakes have undergone dramatic, range-wide declines in their native habitats of Arizona, New Mexico and Mexico. The snakes are now almost entirely limited to small, isolated populations at risk of being driven extinct.

“If these unique, beautiful garter snakes are going to survive, federal officials need to start protecting their habitat,” said Jenny Loda, a Center biologist and attorney working to protect vulnerable amphibians and reptiles. “Delay means death for these extremely vulnerable creatures. Safeguarding the rivers these snakes need to live will also benefit other native species and people.”

After more than a decade of delay in response to the Center’s legal advocacy, the Fish and Wildlife Service protected northern Mexican garter snakes as well as narrow-headed garter snakes as threatened under the Endangered Species Act in 2014. The agency proposed protecting more than 420,000 acres of critical habitat for the snakes along with the listing proposal in 2013, but failed to finalize those habitat protections.

Designating critical habitat is an important step toward ensuring the snakes’ survival. Their decline has been caused by the destruction of their streamside habitats through livestock grazing, water withdrawal and agricultural and urban sprawl, as well as by the introduction and spread of nonnative species like sunfish, bass and crayfish.

The Fish and Wildlife Service found that 83 percent of the northern Mexican garter snake’s populations in the United States and 76 percent of the narrow-headed garter snake’s populations occur at low densities or may already be gone. 

Critical habitat designation would help address the numerous threats by requiring federal agencies to consult with the Service when their actions may result in damage or destruction of the snakes’ habitats.

“Studies show that species with critical habitat protections are twice as likely to be recovering as those without,” said Loda. “It’s time for the Service to stop dragging its feet and comply with the Endangered Species Act by finalizing habitat protections for these threatened snakes.”

The Center petitioned for the listing of the Mexican garter snake in 2003. After several lawsuits, the snake was designated a candidate for Endangered Species Act protection in 2008. In 2011 the Center submitted a status report documenting the need for protection of the narrow-headed garter snake.

Under the Center’s landmark 2011 settlement with the Fish and Wildlife Service, both species were listed as threatened in 2014. 

The northern Mexican garter snake historically existed in every county in Arizona, with additional populations in New Mexico and Mexico. It ranges from olive to olive-brown in color and has three bright, lateral stripes. The northern Mexican garter snakes’ habitat requirements include permanent water, vegetative cover and native prey.

The narrow-headed garter snake is widely considered one of the most aquatic garter snakes. This small- to medium-sized garter snake is tan or gray-brown, has an unusually elongated head, and has brown, black or reddish spots. It lives in the Mogollon Rim in New Mexico and Arizona, in clear and rocky stream habitats.

Narrow-headed garter snake

Narrow-headed garter snake photo by Pierson Hill. This image is available for media use.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.6 million members and online activists dedicated to the protection of endangered species and wild places.

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