(Rodrigo Cunha/)
According to legend, several people have seen alligators and other exotic animals living inside the sewer networks of big cities. There would even be reports of attacks on humans! But the real thing is that it is impossible for an alligator or any other animal to survive inside the sewer itself. The decomposition of excrement releases methane, a gas highly harmful to life.
But what about the constant alligator sightings in Rio de Janeiro? You’ll notice: they are always found in areas with access to the surface, such as culverts, canals and ponds. In fact, some animals end up living in the most superficial galleries or in areas where sewage is discharged into rivers. There is a wide variety of fauna at these points, as shown in the infographic below.
BACTERIA – In the deepest galleries of the sewage network, the only form of life found are bacteria, which manage to survive in an environment taken over by methane gas. Any other living being in here would have certain death!
RATS – In the superficial galleries of the sewage network, which have an exit to the street, such as the manholes, it is possible to find small animals: rats, cockroaches, reptiles such as lizards and lizards, ants, beetles, centipedes and other insects
ALLIGATORS – Only at the dumping points in the rivers can you find larger animals. In these areas, fish feed on sewage residues. There, not only a stray alligator, but also large birds, such as herons, can come up to feed on the fish.