 Because of their large , heavy body size , the adults have no trouble eating prey as large as fully grown rabbits . When prey happens by , they strike with very fast precision from any angle . Once they strike their prey , they hang on to it with their large fangs rather than letting it go and waiting for it to die . This behaviour is very different from the behaviour of other species of vipers . These snakes feed on a variety of birds and mammals , such as <unk> , many different species of rodents , including field mice and rats , as well as hares and rabbits . There are also reports of more unlikely prey items , such as tree monkeys , the brush @-@ tailed <unk> ( <unk> ) and even the small royal antelope ( <unk> ) . 
