The bushmaster is Bothrops asper, also known as fer - de - lance, nauyaca in Mexico and terciopelo in Central america. As nanoboy mentions they are very venemous and feared. When i did fieldwork in veracruz, nauyacas could be found in cornfields and coffee plots as well as in the tropical forests. It is said that Nauyacas do not fear any humans and are very aggresive.