Venom organ failure. Many caterpillars have defensive venom glands associated with specialized bristles on the body, known as urticating hairs, which can be lethal to humans (e.g., that of the "Lonomia" moth), although the venom's strength varies depending on the species. Bees synthesize and employ an acidic venom (apitoxin) to cause pain in those that they sting to defend their hives and food stores, whereas wasps use a chemically different alkaline venom designed to paralyze prey, so it can be stored alive in the food chambers of their young. The use of venom is much more widespread than just these examples.
Snake venom adaptation to assist digestion. However, studies of the western diamondback rattlesnake ("Crotalus atrox"), a snake with highly proteolytic venom, show that venom has no impact on the time required for food to pass through the gut. These various adaptations of venom have also led to considerable debate about the definition of venom and venomous snakes. In the vipers, which have the most highly developed venom delivery apparatus, the venom gland is very large and is surrounded by the masseter or temporal muscle, which consists of two bands, the superior arising from behind the eye, the inferior extending from the gland