RIO DE JANEIRO - Oh, the glories of Rio that await spectators and athletes at the 2016 Olympics: those beaches, that music, the dramatic mountains. And then there are a few thousand alligator-like creatures slithering through sewage-like lagoons.
Some 5,000 to 6,000 broad-snouted caimans live in fetid lagoon systems of western Rio de Janeiro, conservationists say, and there's a chance that visitors could have an encounter with one, though experts hasten to add that the caimans, smaller and less aggressive than alligators or crocodiles, are not considered a threat to humans.
Some of the animals already have taken refuge in ponds being built inside the Olympic golf course, which abuts a once pristine mangrove-filled lagoon that's now thick with tons of raw sewage pumped from nearby high-end condominiums. In fact, with two decades of growth decimating natural habitats, the hardy caimans have become an increasingly common sight in the urban heart of western Rio. The district is the main hub for the 2016 Games and site of the Olympic village, though most events will take place in indoor facilities.
The caimans congregate in a canal in the affluent Recreio dos Bandeirantes suburb that's sandwiched between busy thoroughfares. Beach-bound mothers with toddlers in strollers, neighbors out to walk the dog and pizza delivery boys pause on a narrow wooden footbridge over the canal to observe the caimans.
With few fish surviving in the polluted waters, caiman increasingly rely on handouts from humans, which can range from raw chicken to crackers. They also feed on birds and sewer rats.
"Caimans are like tanks, a very old species with a remarkable capacity for renovation that allows them to survive under extreme conditions where others couldn't," said Ricardo Freitas, an ecology professor who runs the Instituto Jacare, or the Caiman Institute, which aims to protect the reptiles. "But the fact of the matter is that their days are numbered if things don't change drastically."
With a population that's 85 percent male, a serious demographic problem is looming for Rio's caimans, said Freitas, who suspects that the uncontrolled release of raw sewage is behind the gender imbalance. Organic matter raises water temperature and among caimans, high temperatures during a certain stage of incubation result in male offspring.