adult bushmasters can grow up to the length of 2 meters (6.5 ft) to 2.5 meters (8.25 ft), but there have been some which have grown up to the length of 3 meters (10 ft). the largest one ever found was 3.65 meters (12 ft) long, making the bushmasters the longest venomous snakes in the western hemisphere and the longest vipers in the world. they are not the heaviest vipers in the world, but adults usually weigh up to 3 to 5 kg (6.6 to 11 ib).