These Conservationists Are Desperate to Defrost Snake Sperm

Freezing and defrosting snake sperm could be a key to conserving endangered species—but artificial insemination isn’t always easy. It’s hard to pick which species to save in Brazil right now. Yellow fever is tearing through primate populations, wiping out squirrel and howler monkeys. Poachers are nabbing giant anteaters for meat and blue macaws to sell as exotic pets. But conservation biologist Rogério Zacariotti wants to save a venomous yellow viper—the golden lancehead. Which is where Zacariotti comes in. As a graduate student, he moved to California to collaborate with Barbara Durrant, who studies reproduction at the San Diego Zoo. When Durrant and Zacariotti first checked the scientific literature on how to freeze snake semen, they found just about nothing. acariotti, Durrant, and two other scientists published their research in 2011 with the title “117 Cryopreservation of Snake Semen: Are We Frozen In Time?” In the field of herpetology, that’s not always a given. Durrant, Zacariotti, and their colleagues are used to defending their less-than-charismatic subjects to the general public, as well as grant committees. Snakes can be medicinally useful, Zacariotti argues, pointing to certain high blood pressure medications made from their venom. And “in Brazil, they are working on an analgesic from the rattlesnake protein that is stronger than morphine and is not addictive,” he says. Durrant says she hopes to apply the techniques they learn in the lab to other species of snakes and reptiles. “What they’ve done is a very first step in research—it’s just the very beginning,” says Terrence Tiersch, professor at the Louisiana State University school of natural resources and aquatic cryopreservation researcher. So Durrant reached out to Mike Rochford, an invasive species coordinator at Fort Lauderdale, to see if he had any extra python sperm he was willing to send over. Turns out, he did. He mailed Durrant entire vas deferentia, the ducts that hold the sperm, from dead snakes. The bigger samples gave Durrant the computational power she needed to finally find the a combination of cryoprotectants that doesn’t kill the sperm.