When you realize your home’s look hasn’t evolved much since its post-college phase, you put the Ikea bookshelves on Craigslist, start searching for a contractor who won’t drive you crazy, scrutinize endless tile samples and stop considering Pottery Barn too public a venue to fight with your spouse. Then you prepare the neighbors and pay the county.

When you realize your reptile house is “stuck in the ’80s,” as National Zoo biologist Matt Evans did last year, you put your aging non-endangered snakes, turtles and lizards on the Association of Zoos and Aquariums’ “status list” (a Freecycle of sorts for curators), work the phones to find a new home for unwanted animals, and start cashing in favors from former colleagues whose zoos have just the gecko you gotta have. Then you prepare the neighbors: Tell the plant people you need new native plants, the commissary you need new meat, and the vet you need quarantine space. And you cross your fingers and hope no red tape keeps the Smithsonian’s Reptile Discovery Center from getting fresh, new cold blood.

Kinda makes your remodeling look less beastly.

When Dennis Kelly left his post at Zoo Atlanta to take over the National Zoo last year, he made species preservation his top priority. He enlisted Evans and Jim Murphy, a research associate, to do a massive remodeling of its “geriatric” inventory, while revamping its mission: more research, more species protection and more endangered animals.

The Smithsonian’s zoo wasn’t, as Evans says, “doing much in the way of science” or leading the country in species preservation, so the 71-year-old Murphy, a giant in herpetology circles, was called out of semi-retirement to head up the Reptile Discovery Center.

“Firing up the herpetologists is Jim’s forte,” said David Chiszar, an animal behaviorist and snake specialist at the University of Colorado at Boulder. In terms of research and journal contributions, Chiszar says, “Murphy is probably in the top five across all zoos and across all the years we have had zoos in the U.S.”

It was the conservation aspect that lured Murphy out of semi-retirement: “I am convinced that we are in the midst of the sixth mass extinction event of animals and plants, caused by humans,” he says. The fifth cleared the planet of dinosaurs. “I know hundreds of biologists, and not one is optimistic. It is incumbent upon me to alert others to this looming catastrophe.”

* * *

With every new endangered Malagasy leaf-tailed gecko now calling Woodley Park home, Evans and Murphy are shifting the Reptile Discovery Center from a static, but crowd-pleasing, collection that hadn’t turned over in decades to one that has 13 new species.

To make room for the 33 and counting newcomers, the reptile center team “deaccessioned” 57 animals. Deaccessioning is the right-sizing of the museum world. One day, you’re hanging out with the other leopard geckos munching on mealworms, the next you’re at the Bramble Park Zoo in South Dakota.

But think about it: It is not that easy to find a good home for a leopard gecko.

“Wheeling and dealing,” the seven-person reptile house staff found new leafy cubicles and warm waters for every last one of its downsized crew, Evans says. It got the Staten Island Zoo, known for its robust snake collection, to take on a few more and the St. Augustine Alligator Farm to welcome a crocodile that sat on the status list for more than a year.

This wasn’t a wholesale gutting of geckos or turnover of turtles. If you’ve always loved watching that Aldabra tortoise the size of a coffee table gnaw on carrots, you still can. “We are keeping virtually all of the former species, just cutting back on numbers,” Murphy says. “In some cases, the reptiles are so old that we are reluctant to move them, even though there might be another zoo interested in acquiring them.”

Nor is it easy getting an endangered species.

Murphy credits many new acquisitions to Evans’s endless, spirited bartering and “golden tongue,” while Evans, 33, can’t say enough about his mentor’s decades of connections and respected position in the tightknit herpetological community.

“Jim has such a history of reaching out and bringing so many different communities together — hobbyists, researchers, zoo curators, students,” says Dwight Lawson, deputy director at Zoo Atlanta.

“Look, we’re an odd bunch who grew up scaring our parents with our weird collections of lizards in jars in the basements and keep to ourselves,” Murphy says. “Knowing everyone helps. If I can call up a former employee and remind him about that recommendation letter I wrote and get him to send me something on our wish list from his zoo, that’s good for more than just giving visitors something new to look at.”

That recommendation-letter reminder is how the National Zoo became home to half a dozen former San Diego Zoo inhabitants, including the endangered spider tortoise. The number of the palm-size tortoises in the world may have already fallen by 90 percent. They’re one of the many endangered tortoises in Madagascar, where despite bans, killings are commonplace.

A source of protein in a poor country, the turtles are hunted despite laws protecting them. In addition, loss of habitat and a high going rate on the black market have made their numbers alarmingly low. “People need to realize what’s happening to the biodiversity on this planet,” Murphy says. “And the best way to do that often is to bring the animal at risk right under their noses.”

The veteran herpetologist and the young biologist have enhanced the reptile house with the following additions: three false water cobras, two leaf-tailed geckos, three green tree monitors, two fantastic leaf-tailed geckos, three Hamilton’s turtles, five New Caledonian giant geckos, three spider tortoises, two Timor pythons, two Fiji Island banded iguanas, two Solomon Island prehensile-tailed skinks, four spiny-headed tree frogs, one caiman lizard and one Merten’s water monitor.

Coming attractions include two black-headed pythons, one Eastern indigo snake, another caiman lizard, two impressed tortoises and 18 hellbenders. (Hellbenders, cousins to the Japanese giant salamanders, usually measure about two feet and are known to wrap their huge mouths around fishing lines in streams in the southeastern United States.) That brings the reptile house’s current population to 381 specimens (give or take a few tadpoles), representing 83 species.

All these trades go on without zoos exchanging a dime. They operate under an honor code, giving one another new animals, to thwart smuggled wildlife trading. It’s a booming, difficult-to-quantify market, but most estimates put the international exotic pet trade between $10 billion and $20 billion, with the United States accounting for $6 billion. The Justice Department estimates that profits from international wildlife smuggling are second only to drug trafficking. Exotic-pet collectors and those who use the meat for food and organs for medicinal purposes have pushed the black market rate for radiated tortoises from Madagascar to $30,000.

* * *

Dealing with clumsy moving crews is nothing compared with the logistics of bringing in new species and shipping out old ones. “I just don’t think when people walk through the doors that they truly understand what happens beyond the glass,” Evans says. “Tanks of little baby lizards back here being monitored round-the-clock, trips to native countries, breeding programs, paperwork, phone calls, the negotiating — just so much work.”

Once a new home is found for an animal, vets at the National Zoo have to make sure it’s disease-free and healthy enough to fly. Once cleared, the animal can’t leave unless the receiving zoo has space to quarantine and house the newcomer. And if all that lines up, the temperature must also be ideal for endangered, fragile reptiles to travel. The window is basically a few months in the spring and fall.

None of the National Zoo’s arrivals or departures has been dead on arrival since the overhaul began, Evans notes proudly, like a homeowner with a break-free move. (How do you pack a python? Put the snake in a breathable plastic bag, put the bag in a ventilated box, toss in some cold or hot packs, then put that box in a bigger box.)

Once an animal arrives at the zoo, it must stay in quarantine: 90 days for snakes, 30 for other reptiles and amphibians. During that period, reptile center staff members can have no contact with their new charge. “It’s like having your kids living in transitional housing before you bring them home from the hospital,” Evans said. “I am constantly on the phone with the vet [about] a new arrival: ‘How much did he eat? Did he sleep?’ ”

Meanwhile, the staff is working with the zoo’s facilities folks to build new habitats or find the right humidifier at Wal-Mart to re-create a cloud forest for the Panamanian golden frog.

Then there’s the food. With each new arrival comes a new diet. Although some can chomp away on local leaves, others demand plants native to their country — which requires the zoo’s horticulture department to add to its shopping list of vendors and importers.

Like a parent bent on finding just the right organic baby food, Evans doesn’t take shortcuts for animals with specialized diets. Ever since the reptile house welcomed a tree-perching, red-headed caiman lizard, a live-snail vendor has added another Connecticut Avenue stop to its route. While some escargots may wind up down the hill at a fancy restaurant, a dozen a week are destined for the cement-crusher jowls of the caiman lizard, which dives into the water and uses its forked tongue as a snail sonar. After pulverizing the shell with its powerful jaws and teeth, the caiman spits out the shell fragments.

Accompanying each step of this complicated animal-acquisition dance is enough paperwork to line every cage in the reptile house a few times over. The handoff of one species can take five months.

* * *

All this won’t mean much if the highly endangered residents don’t make babies.

As part of its more robust species-protection role, the Reptile Discovery Center has enrolled 18 species into one of the Association of Zoos and Aquariums’ population-management programs. Seven are in the highest-maintenance program, the Species Survival Plan: the Panamanian golden frog, Chinese alligator, Cuban crocodile, Komodo dragon, Malagasy leaf-tailed gecko, Fiji Island iguana, and radiated tortoise.

The matchmaking duty is more rigorous than just tossing two reptiles into a cage. The center first has to find reptiles from different bloodlines. “You don’t want cousins marrying cousins,” Murphy says, citing the risk that “inbreeding depression” poses to evolutionary success.

Oh, and not all couples start snuggling snouts from the get-go. While the Cuban crocs didn’t keep their handlers waiting long, the Fiji Island iguanas proved to be a less amorous pair. When Evans introduced the female into the enclosure, the bigger male iguana lunged at her with no romantic intentions. Evans and the keepers beefed up her weight and confidence, scheduled “dates” at different times of the breeding season and recently reintroduced the two into the same habitat, where one recent summer day they were sunbathing quietly together.

Once the animals hook up, these programs demand a level of oversight that would exhaust the most hovering of helicopter parents.

Nestled in a closet-size space behind the Panamanian frog display is an incubator carefully set between 89.5 and 90.5 degrees. It is home to four Cuban crocodile eggs from the endangered croc’s first clutch. Hunted for their meat and skin, Cuban crocs recently gained a new enemy: American crocs. Their northern neighbors are moving into their waters and hybridizing with wild populations found only in the Cuban archipelago. Making it worse, American male crocs usually take more than one mate, thereby diluting the gene pool even more. Fewer than 3,000 genetically pure Cuban crocodiles exist in the wild.

The National Zoo, and others, need more male Cubans, and the temperature of the egg determines its sex. “One degree higher and one degree lower, and it’s a disaster!” Evans says.

To ensure that an all-male quartet debuts after 90 days, the staff monitors the eggs like a hungry hawk. Evans can’t help but open the door of the incubator, but he must resist touching the eggs, as any movement can kill the embryo inside.

At Day 45 of the 90-day incubation, Evans was hopeful that all four boys would come out snapping soon. But when he and Murphy checked in at Day 90, all were empty. Just hollow shells.

Murphy was disappointed.

“We did everything right; our incubator worked,” he says. “But animals in captive environments, no matter what we try to do and how hard we try, tend to end whatever they ... please.”

Some of his colleagues call themselves “extinction biologists” and “taxonomy pathologists.” He isn’t quite there yet, but without doubt, he is rattled by the accelerating rate of extinction.

“When I was a kid, I never imagined that I might see the disappearance of two major predators: tigers and polar bears. This freaks me out,” Murphy says. “Perhaps the younger generation can accomplish what we have failed to do: save our planet.”

Amanda Long is a freelance writer who lives in Falls Church. She can be reached at wpmagazine@washpost.com.