The US ridge-nosed rattlesnake population is in trouble. Here’s how the LA Zoo is trying to help

The Los Angeles Zoo is caring for more than a dozen New Mexico ridge-nosed rattlesnakes, including six babies, as part of an international recovery program for the federally threatened species.

The snakes are found in an isolated habitat between U.S. and Mexico mountain ranges, but the population has dropped to possibly less than a few hundred in our neck of the woods.

The “Project Obscurus” program — a nod to their scientific name crotalus willardi obscurus — hopes to genetically rescue the rattlesnakes in the U.S.

Tony Daly-Crews, founder of the Rattlesnake Conversancy, told LAist that without these conservation efforts, the species was likely to be stamped out from the area.

“This project is the first on the ground recovery action that's been taken for the species since it was listed to the Endangered Species Act 50 years ago,” he said. “This is a big experiment, we don't know all of it's going to work … but we're confident that we're going to be able to do something here.”

Not your usual L.A. rattlesnakes

These grayish, well-camouflaged rattlesnakes are tiny compared to the ones you try to avoid hiking in SoCal’s hills, no more than 2 feet long.

And 15 of them are at the L.A. Zoo, including six out of the 20 babies in the program, with the rest split between the Arizona-Sonora Desert Museum and San Antonio Zoo.

Byron Wusstig, acting curator of ectotherms at the L.A. Zoo, told LAist that all of the little ones could be released into the wild once they mature.

“What we found with these youngsters so far is that they're really hearty babies,” he said. “They feed really well right from the beginning, and that was a huge relief for us here at the zoo.”

New Mexico ridge-nosed rattlesnake.

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Jamie Pham

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Courtesy of Los Angeles Zoo

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The snakes eat a variety of things, including birds, rodents, lizards, and centipedes, which Daly-Crews noted they wouldn’t have known without past research. He said he’s looking forward to Project Obscurus adding onto that knowledge through temperature data, which will help them better care for the animals in captivity.

“Seeing the newborn babies born here at the zoo, and how well they adapted to life and human care right from the get go, is really rewarding to me,” Wusstig said. “I think it provides a bright future for the species, and the captive breeding program that we're beginning to establish here.”

One animal at a time

In August, more than 40 experts spent a week in the mountains of Sierra San Luis, Mexico, collecting ridge-nosed rattlesnakes for the first phase of the project.

They spent up to 15 hours a day hiking in the desert, looking for these “incredibly difficult to detect” animals — with a paramedic and anti-venom on hand, just in case.

“You're looking for a tiny gray snake amongst a bunch of gray rocks, so it's a huge challenge,” Wusstig said.

The three zoos took home 10 each, which work as the founders of the breeding program. Another portion went directly into the wild in the U.S., including a female who gave birth as she was being released. All zoo partners have gone on to have successful live births since.

Daly-Crews said it’s a monumental effort for a species that, frankly, a lot of people don’t know or care about. But he said these little rattlesnakes are a representation of the ecosystem and the world around them.

“We don't expect you to love rattlesnakes,” he said. “But we'd appreciate it if people could understand the importance of these animals, and their ecosystems, and at least leave them alone if they see them in the wild.”