SARAH MIN HELLER Cronkite News
PHOENIX — An endangered species for nearly a decade, the narrow-headed garter snake is getting new life and help from scientists at the Phoenix Zoo.
Tara Harris, director of conservation and science at the Phoenix Zoo, said 40 of these snakes were born at the Arthur L. and Elaine V. Johnson Conservation Center in 2022. That was by far the most since the program began in 2007, and Harris hopes the zoo gets enough a successful year.
“These narrow-headed garter snakes are Arizonans just like you and me, but their future in our state is uncertain and they need our help,” Harris said.
The aquatic snake, which is native to central and eastern Arizona and western New Mexico, has been in decline for the past two or three decades, said Mason Ryan, garter snake project coordinator at the Arizona Game and Fish Department.
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The snake lives in cool, rocky areas in or near streams; it has been listed as threatened under the US Fish and Wildlife Service since 2014 and is protected by the Arizona Game and Fish Commission.
In general, snakes are useful creatures, act as natural pest control and add to the food web’s biodiversity, Ryan said. These garter snakes are endangered mainly due to invasive species in the state, and boosting their population has proven difficult.
Invasive species such as crawfish and bullfrogs that compete with or eat the snakes are a major threat, Harris said. The garter snakes specialize in eating fish, which doesn’t help, Ryan said. Arizona ranks as the highest state in the percentage of declining native fish species, according to the Federal Register.
Birds of prey, raccoons and other snakes are some of the predators of the narrow-headed garter snake.
“The species is quite difficult to breed,” Ryan added, explaining that breeding can take years to tell and releases can have a big impact. The Phoenix Zoo has bred only 84 narrow-headed garter snakes since the program began in 2007. The snakes are born alive, not hatched from an egg.
Ryan said the snakes are released into Gila County’s Canyon Creek, which stretches from the Tonto National Forest to the Fort Apache Reservation. There were 24 young narrow-headed garter snakes and one adult released last summer, Harris said, adding that the snakes are released at different stages of development to see which ones survive best.
Because the snakes are usually about 3 feet long or less and difficult to find, Harris said they are marked with numbers that can be read using a black light. Ryan said larger garter snakes may have a tracking device implanted under the skin.
Harris said finding a method to get the snakes to breed was a learning process. The zoo uses an enclosure that mimics the snake’s natural habitat with an area for brumation – a sluggish state for garter snakes in winter – running water, fish and trees.
The youths live in the “snake lab,” Harris said. They are stored in a tank with a lid that lets in heat and light from a heat lamp. Inside is almost all water with fish, plus a platform with small shelters on the surface of the water.
In 2021, the federal government helped by designating 447 miles of protected streams for the garter snakes, equivalent to 23,785 protected acres in Arizona and New Mexico, according to the Center for Biological Diversity.
Harris said the public can help protect these snakes by not using invasive species as bait and not bringing in game fish. Teaching and learning about the garter snakes and volunteering is another way to help, Ryan said.
“It’s nice to have these creatures in the landscape,” Ryan said, adding that it would be sad if future generations could never see the garter snakes.
The Phoenix Zoo, which has focused on plant and animal conservation for decades, is currently working to increase the population of black-footed lizards, Chiricahua leopard frogs, ferruginous pygmy owls, desert pupfish and more, in addition to the narrow-headed garter snake.