In Argentina’s Chaco region, wild caiman and captive caiman can be close neighbors. Those living on ranches are generally bound for the butcher or belt-maker, whereas their wild counterparts live out their lives in nearby water holes. While it’s a relationship that’s helped the wild ones survive—the ranches stem the demand for hunting wild crocodilians—lately, it’s posing some problems.

Caiman ranchers collect eggs from the wild and go on each year to raise more than 100,000 of the reptiles for the purpose of shoes, belts, and other leather products. About 10 percent of these caiman are luckier lizards. The ranchers return them, as hatchlings, back to the wild. The trouble comes when these farm-raised reptiles have been exposed to Salmonella bacteria.

Salmonella can spread between humans, reptiles, and other animals. Some strains of the bacterium are harmful and occasionally, deadly. WCS health experts found two such strains in an Argentine ranching facility. Surveying the ranch between 2001 and 2005, they screened more than 100 caiman for Salmonella bacteria. In 2002, the results for 77 percent of those crocs came up positive.

The caiman ranch had volunteered for the assessment of its captive crocs. But currently Argentina has no standardized health surveillance system for its caiman operations.

“An accidental introduction of Salmonella or other pathogens into the environment during the release of captive-raised caimans could pose a health threat to wild caiman populations and other susceptible wildlife species, including some birds and mammals,” said the study’s lead author Marcela Uhart of WCS’s Global Health program. “Preventive measures to detect the presence of harmful pathogens in caiman ranching facilities can help reduce potential health risks to humans as well as protect wild animal populations.”

Robert Cook, executive vice president and general director of WCS’s Living Institutions, adds that putting a monitoring system in place could go a long way towards mending the problem. “Caimans almost became extinct in the late 1960s as a result of over-hunting for their hides,” he said. “Today, the International Union for Conservation of Nature supports caiman ranches as a tool for crocodilian conservation. A health monitoring system would help ensure the sustainability of both reintroduction and commercial aspects of caiman ranching as well as the safety of products for human usage.”