The woman snatched the child away and called the fire brigade, who trapped the 1.5m-long (5ft) alligator.
The firefighters said the family was lucky the reptile was not hungry.
Firefighter Captain Luiz Claudio Farias said it could have seriously hurt or even killed the boy.
The alligator was taken from the house and released in another area. Link -via Arbroath
(Image credit: Flickr user Mohammed Al-Naser)