Why do spitting cobras spit venom?

The spitting mechanism is actually an adaptation, which protects spitting cobras, from predators larger than themselves. When threatened, these cobras eject a spray of venom into the eyes of their predator, with incredible accuracy! The spray, although not fatal, causes temporary blindness, which if not treated, results in permanent blindness. Spitting cobras are not particularly muscular, and do not have the strength to squeeze and kill large prey. Their fangs are small and if they bite, they need to hold on to their prey for a long time, before it dies. If they bite a large predator, they will have to bite it and wait till it dies. In this struggle of holding on to larger prey, if the prey gets loose, it can kill the spitting cobra, even after injecting the venom. This is because the venom takes time to kill the predator. Thus, it is important for the spitting cobra to disable its predator, as quickly as possible. Ashe's spitting cobra also commonly known as the large brown spitting cobra, is the largest species of spitting cobra found in world today. Its venom is considered to be the most poisonous of all spitting cobras, and has the capacity to inject twice the amount of venom, any snake can inject in one bite. One bite has enough venom to kill 25 to 30 people.