Every year on 1 May, San Domenico di Sora gets some spectacularly bizarre accessories. During a religious procession in the Italian village of Cocullo, a statue of the saint is adorned with harmless snakes (above). The origins of this festa dei serpari, or festival of the snake-catchers, may date back centuries.

Gianpaolo Montinaro, a biologist at the University of Bari Aldo Moro, Italy, was eager to study the snakes, but it took him years to convince the villagers that a long-term research project would help, rather than harm, the reptiles. Legally, the serpari can only catch local snakes, such as green whip snakes (Hierophis viridiflavus) and four-lined snakes (Elaphe quatuorlineata, shown top and below), in the weeks up to the procession. Shortly after, the animals are released (pictured bottom) at the exact spot where they were found, which leaves little time for Montinaro and his team to study them.

Before each procession, the researchers transform the local museum into a pop-up health clinic for snakes. They measure each animal鈥檚 length and weight, take swabs and blood samples, and implant microchips to identify repeat visitors. They also treat wounds and remove parasites from the snakes鈥� bodies and mouths (pictured above).

Almost 20 years鈥� worth of data indicates the snakes are thriving, with no sign of a dangerous fungal disease that has appeared in other European populations. We might benefit as well. 鈥淪nakes pick up microbes on the ground,鈥� says Montinaro. 鈥淭hat helps us to look out for novel pathogens that could infect humans.鈥�