 In their description of B. gabonica , Spawls et al .. ( 2004 ) give an average total length of 80 – 130 cm ( 32 to 51 @.@ 5 in ) , with a maximum total length of 175 cm ( 69 @.@ 3 in ) , saying the species may possibly grow larger still . They acknowledge reports of specimens over 1 @.@ 8 m ( 6 ft ) , or even over 2 m ( 6 @.@ 5 ft ) in total length , but claim there is no evidence to support this . A large specimen of exactly 1 @.@ 8 m ( 5 @.@ 9 ft ) total length , caught in 1973 , was found to have weighed 11 @.@ 3 kg ( 25 lb ) with an empty stomach . Very large specimens may possibly weigh up to 20 kg ( 44 lb ) , which would rank them as the world 's heaviest venomous snake ahead of the Eastern <unk> <unk> , but these masses are not known to have been verified . 
