The Yellow Boa or Boa Coridyu is native to swamps, mainly from southern Brazil to northern Argentina. Buenos Aires Zoo. In context at www.dixpix.ca/Amazon/fauna/snakes/index.html
The Rainbow Boa or Boa Arcoiris is found from southeastern Bolivia to northern Argentina, preferring more open areas. Serpentario de Mendoza, Argentina.
It hisses and bites, but no venom. Known as the Short-tailed Boa or as Boa de Amaral this species is native from Bolivia and southern Brazil to northern Argentina. Serpentario Armero, amazonian Colombia. In context at www.dixpix.ca/Amazon/fauna/snakes/index.html
This is the 'official' Boa Constrictor, native to Northern South America. Also known as the Colombian Red-tail Boa. Buenos Aires Zoo. In context at www.dixpix.ca/Amazon/fauna/snakes/index.html