This paper documents the presence of rattlesnakes, as an invasive species, in several municipalities of the State of Rio de Janeiro. As previous registers indicate, these snakes probably invaded at least the municipality of Valença carried by floodwaters between the decades of 1950 and 1960. In the new environment, along the margins of the Rio Preto, these snakes were able to establish new populations in deforested areas turned into cattle grazing. The presence of rattlesnake in the municipality of Barra do Piraí, a municipality that has no border with Rio Preto, however, indicates that these snakes dispersal into new areas may be facilitated by open areas, represented by pastures, created after deforestations.
Atlantic Forest; habitat disturbance; range expansion; rattlesnake; snake
