Venom is a key evolutionary innovation that plays a primary role in prey subjugation within venomous snakes. However, while there is a growing body of literature indicating the activity of snake venoms can vary dramatically between taxa, the majority of studies have historically focussed on the activity of snake venoms with regards only towards human or mammalian physiologies. Species of viperid from the Bitis genus are known for their complex venom compositions and wide range of venom activities. To investigate the ecologically differential activity of Bitis venoms we have conducted in vitro clotting assays utilising the plasma of R. marina, G. gallus, T. scincoides and R. norvegicus as model organisms for the amphibian, avian, lizard and rodent coagulation cascades respectively. Our results have shown a range of differential activities across the vertebrate coagulation cascade. Remarkably, B. caudalis (Messina locality) venom which is known to have coagulant activity upon human fibrinogen also had coagulant activity upon both amphibian and lizard plasma while conversely having anticoagulant activity upon avian plasma. The lizard feeding specialist B. peringueyi, as well as its close relative B. schneideri, showed coagulant activity upon lizard plasma although had no effect upon amphibian, avian or rodent plasma. The medically important B. gabonica showed no ability to clot amphibian, avian or lizard plasma despite being known to possess toxins with a coagulant activity upon human coagulation factors. Our results highlight the importance of studying the activities of venoms on relevant models when making conclusions about the ecological role of venoms, as well as further widening our understanding of how variable the activity of toxins can be on physiologically different organisms.