 <unk> gabonica , most commonly known as the Gaboon viper , is a viper species found in the rainforests and <unk> of sub @-@ Saharan Africa . Like all vipers , it is venomous . It is not only the largest member of the genus <unk> , but also the world 's heaviest <unk> , and it has the longest fangs – up to 2 inches in length ( 5 cm ) , and it has highest venom yield of any snake . Two subspecies are currently recognized , including the nominate subspecies described here . 
