Thousands of alligator-like reptiles have swarmed in to warm water very close to the site where the 2016 Olympic Games will be held.
The creatures, called caimans, are thought to have been attracted by the warmer water in Rio de Janeiro, caused by pollution in the densely populated city.
Although the reptiles continue to slither their way through sewage-filled lagoons, experts say they pose no real threat to humans.
The caimans are both smaller and less aggressive than alligators or crocodiles.
They have gathered in a canal in the affluent Recreio dos Bandeirantes suburb, right between two busy roads.
And some have even begun to move into the ponds located on the Olympic golf course.
Both sites are close to where the Olympic village will be located in three years time.
Biologist Ricardo Freitas, founder of the Caiman Institute, told Sky News: “A big problem would be the lack of food, but people feed them so you have food, high temperature and the caimans, especially the larger ones, start to concentrate in these places and dominate the territory.”