Some snakes produce venom. Some do not. Of the ones that do, a small portion have the ability to “project” their venom at a distance.
Venom so powerful that it can kill an elephant does a snake little good if it dies in the encounter as well. Nature has a solution: “spit”.
“Spitting” is a defensive ability some snakes have. It is defensive in that it is not used for hunting as often times the animal the snake is defending against is too large to process. Biting is for “offensive” encounters and “spitting” snakes can (and do) bite.
Oh BTW, it is not just cobras that can spit venom. The Mangshan Pit Viper can spit venom as well. Although, all the other of spitting snakes are from the elipadae family (cobras).
The mechanism by which snakes spit venom is quite simple. Like most other snakes that inject venom, spitting snakes have hollow fangs. The difference with spitting snakes is the outlet, or hole, for the venom is more front facing and smaller.
The snakes instinctively aim for the eyes with precision. They are so precise that they often “lead” to where the eyes will go. They alter the force and angles based on their target’s distance. It works really well. There is even emerging evidence that the venom of spitting snakes leans more towards the use of cytotoxins and myotoxins verses neurotoxins found in most elipadae. Cytotoxins and myotoxins cause more damage at the site of envenomation and tend to cause more pain. Neurotoxins often induce a type of paralysis and are usually deadlier.
You can’t really put a nice bow on this. This is pretty close to nightmare fuel. I am fairly certain that if aliens do exist it will be our planet and not theirs that has scariest animals. It’s a tube with a head that has poisonous daggers that can FRIGGIN SHOOT POISON!
Beware they live.