Kym McDonough is in a race against the clock—the biological clock, that is, of the desert tortoise.

With fall well under way, Nevada's state reptile population is inching closer to brumation, which is the cold-blooded version of hibernation, in which tortoises hunker down in burrows to get through the cold months, occasionally rousing from their slumber on warmer winter days.

Time is ticking for McDonough, the Northern Nevada adoption coordinator for the nonprofit Tortoise Group, to find a new home for Dee, an adult desert tortoise being given up for adoption by her elderly Reno caretaker, Jean Norris. Norris is concerned that her own slowing mobility will make it hard for her to care for the two tortoises she currently has. Each will go to a different family, as Nevada law limits legal desert tortoise adoption to one per household, citing concerns of overbreeding and tortoise-to-tortoise disease transmission.

It's McDonough's job to relocate pet desert tortoises whose caretakers either cannot or no longer want to care for their crawling critters anymore. Tortoise Group is the only organization allowed by Nevada's government to carry out legal adoptions as a means of conservation for this federally endangered species.

"My job is not only to adopt out but also to educate," said McDonough, who hosts brumation clinics to show tortoise caretakers how to keep their critters comfy come sleep season. "A lot of people don't even know that it's something that you can do up here," she said of legal desert tortoise adoption in Northern Nevada.

Although Dee is being adopted out of Reno, most tortoises that McDonough relocates get hand-delivered to her by a Tortoise Group colleague making the long drive from Las Vegas. Wild desert tortoise populations in their native Mojave and Sonoran deserts have been declining—largely the result of human encroachment on their habitat, according to the U.S. Fish and Wildlife Service (FWS). However, captive desert tortoises are experiencing just the opposite problem: the greater Las Vegas area is home to anywhere between an estimated 137,172 and 153,783 pet desert tortoises, according to a 2018 study by the University of Nevada, Las Vegas. The FWS points to uncontrolled breeding as the cause of such staggering numbers, with thousands of them ending up as unwanted pets, according to the agency.

Fortunately, for tortoises, they can live outside their climatic comfort zone, which is the southern reaches of the Silver State, but that's provided the right custodian comes along.

That's right: custodian. The state entrusts Nevada residents to act as legal custodians—by law, no one "owns" an adopted desert tortoise—provided such residents undergo a rigorous yard approval process conducted by Tortoise Group staff, such as McDonough. Nevada residents who acquired their desert tortoise before August 1989, when the species was added to the Endangered Species Act, are exempt from the yard approval process.

Shari and Sarah Byrnes went through such a process earlier this spring. The mother-daughter duo met with McDonough in the Byrnes family's south Reno backyard to find out what changes they would need to make to their property before it could be deemed tortoise-friendly. Among the requirements: constructing a rainproof, concrete burrow; adding a fence around their garden to block flowers that are poisonous to a tortoise, such as calla lilies; and planting flowers that are healthy to a tortoise, such as honeysuckle and petunias.

The burrow the Byrnes family built has a south-face opening to prevent the northerly, hot summer sun from shining into Dee's resting place. Although wild tortoises in the Mojave and Sonoran deserts build burrows underground, caretakers of captive tortoises in Northern Nevada must build theirs above, since the ground can freeze. Beneath the sand floor of the burrow, there is a foundation consisting of plywood and a plastic tarp to insulate the structure from frigid soil.

After tortoise-tailoring their yard in the spring, and waiting months on Tortoise Group's adoption list, the Byrneses made it to the front of the line in late September, when they welcomed Dee to her new home—marking McDonough's 40th desert tortoise adoption of the year.

"I always want an animal of any kind ever," said daughter Sarah Byrnes in her backyard as Dee meandered through the lawn, crawling past Shiloh, a miniature Australian shepherd, and making her way toward twin cats Benjamin and Franklin.

Quick to draw an entourage of animals by her side, Dee likely won't be hard to find, should the Byrneses need to take her inside on a cold day. But since she's a tiny tortoise in a big backyard, the family isn't taking any chances. Shari plans to install a geo-tracking Tile device, similar to the kind often attached to keys, on Dee's shell.

"We're going high-tech with this tortoise," Shari said.

It's a practice welcomed by Tortoise Group as one small step toward helping keep this small threatened species out of harm's way.

Benjamin Payne is a graduate student at the Reynolds School of Journalism.