When this failed to deter me, he brought out the big guns. Out from the front of his short, fixed fangs came a spurt of sickly looking liquid, aimed directly for my eyes.
It splattered on the glass window between us. With rag in hand, I finished cleaning the front of his tank, then moved on to the next snake.
There are few adaptations among venomous snakes -any snakes, really - more sophisticated that the defensive maneuvers of the spitting cobras.
Most venomous snakes use their toxins primarily for subduing and killing their prey; its defensive uses are a utilitarian afterthought. Venom is, biologically, expensive to produce, so snakes tend not to waste it needlessly. It is for that reason that it is not unusual for a person bitten by a venomous snake to experience a dry bite, or one in which no venom is actually injected.
About half of the two-dozen or so species of cobra, however, have the ability to spit their venom, which is used solely for defensive purposes. Venom is forced out of small holes at the front of their fangs, sending it in a directed squirt towards an attacker. If it lands on bare, exposed skin, there is no harmful consequence for the victim. If it gets into an open wound, it can be dangerous. If it gets into the eyes, permanent blindness is a possible result if no treatment is offered.
From BBC's Life in Cold Blood - Sir David demonstrates the defensive capabilities of a spitting cobra
Even if the snake does bite, oftentimes it will have expended so much venom spitting that there won't be much, if any, left for the bite itself. That's what happened to Joe Slowinski, the hero of Jamie James' The Snake Charmer... and from a species of spitting cobra that he had just discovered, to make it more insulting.
While they may be "safer" to work with than some other venomous snakes, spitting cobras are capable of inflicting a world of pain upon unwary keepers and handlers. The victim who gets spit in the eyes, it is said, gets a close approximation of what it feels like to have battery acid poured into his or her eyeballs. How do I know? Not because I've ever taken a hit. Because I've read the accounts of some people who have. In addition to his bite, Joe Slowinski took an eyeful of the stuff. Peter Brazaitis, author of You Belong In a Zoo! never got sprayed, but had the misfortune of rubbing his eyes without realizing that he had a drop of the stuff on his hand first. Never made that mistake again, I'm willing to bet. If you do get venom in the eye, immediate first aid involves flushing the eyes with water or saline solution. Some cultures through Africa and Asia that share their lands with spitting cobras use fruit juices... or urine.
I might opt for the blindness.