Venom Delivery of Snakes as High-Pressure and Low-Pressure Systems

Abstract

Two fundamentally different venom delivery systems are found among advanced snakes. One is a high-pressure system present in viperids and elapids wherein a pulse of venom is delivered quickly by a sudden pressure surge. The other is a low-pressure system found in some colubrids wherein release of oral secretions is more protracted. These differences help account for the great variation in medical signs and symptoms following bites of humans by colubrid snakes. Further, the high-pressure venom system of elapids and viperids represents an evolutionary innovation in snakes accompanied by a change from a mechanical to a chemical predatory strategy.