The Bushmasters apparently don't get as far north as Belize.
Here's a good site for descriptions and ranges of various poisonous snakes:
http://danger.mongabay.com/survival/afm/e.htmlHere's a Yararaca Lance-head killed in northern Artgentina in winter. Although I have several pix of dead snakes, none were killed by me, but they were all(save the mamba) in places where they could have easily caused injury or worse to people/dogs.