Will the crabs survive?

To ensure the crabs’ survival, researchers need funds to study them and permission from the city to implement grates over exposed canals so that birds can’t easily prey on them. “We’d love to study these animals because they deserve to not only be studied but also saved,” says Damiani. “This population cannot disappear.” (Read more: Italy’s ancient dolphin population is also fighting for survival.)

So far, the city has denied petitions from Damiani and his colleagues to implement grates and signs informing passersby of the crabs’ existence. The reasoning, he says, is that doing so would mar the view of the ancient monuments: “They don’t care about the crabs, they care more about tourists going to see the Colosseum.”

While the future of Rome’s ancient population of river crabs is nebulous, Seminara hopes that one day there will be enough funds and interest to further investigate the population. For now, crab fans must wait and see if the reclusive creatures can continue to eke out an existence deep beneath the city’s ruins.

“Their existence is certainly folklorish. It would be like finding a crab living in Central Park,” he says. “This is a unique animal. The fact that in the Roman Forum there is the only large freshwater crustacean that we have in Italian waters, has and will always generate a certain amazement.”