Here are some interesting snake facts, whether they're relevent or not. ^_^.
The cobra is a venomous snake with a deadly bite.
The king cobra, is the world's longest venomous snake. Arbok is pretty huge, so it could be a king cobra.
However, my theory is that it's a spitting cobra, which can spit venom several feet, and if it goes in the victim's eyes, causes temporary blindness. I think Arbok is one because of its acid attack, which sounds just like this.
Boas are known to kill their prey by squeezing it/suffocating it in its coils rather than through venomous bites like the cobra. This fits in with Aabo's wrap-type attacks.
Snakes, particularly cobras, are known for having mongeese as their enemies. This is sort of true - mongeese don't mind a snakey meal - but usually won't bother with the danger of trying to catch it. However, this was played upon in "Ghost of Maiden's Peak" when Ekans was terrified of a mongoose.
Okay, can I just say something cool I read, boas actually have live young, not eggs. That has no relevence at all but I thought it was interesting. ^_^.
Rattlesnakes are very heavy snakes (heheh, put Ekans on a diet), and don't have a very good sense of sight or hearing. They make up for it with heat sensors on their snouts, feeling movement through the ground, and a great sense of smell. They don't attack often but when they do, their venom is quite powerful, and the larger the rattler, the more dangerous its bite.
Baby cobra can defend themselves a few hours after birth.
Dead snakes can still strike with their venom by reflex action.
Most snakes swallow their prey alive and whole, but venomous ones usually wait until their venom has killed it. They like eating things like birds, lizards, fish, frogs and rabbits.
Cobras like eating eggs. Ekans' Pokedex info says it likes to eat eggs of Pidgey and Spearow whole. ^_^.
Snakes don't require a lot of feeding.
King cobra sometimes eat other snakes.
Snakes are actually quite intelligent.
A fairly vague fact is this, but I was told most cobras were about 10 feet when fully grown. Arbok is about 11 feet, so that's pretty close.
Snakes have no eyelids.
Snakes are reptiles, and cold blooded, so they love to curl up in the sun.
Most snakes are actually very shy.