From what I can see, it's a moccasin (Aka Cotton mouth) they're very dangerous and prone to strike. Not always very lengthy, they're a VERY stout viper with a potent venom. The southern states are crawling with them, here in Arkansas they are a frequent non-favorite and one of those "kill on sight" snakes. They're rumored to smell although I've never come across it... Definitely one to avoid, but when in doubt check the shape of the head.

A wide spade shape means it's a viper, more often than not.. that's you're best chance of identifying a poisonous snake. I'm guessing you're from Florida? I'm not too awful familiar with the wildlife around there but I don't think it's that dissimilar to here in AR. Hope I helped!

~Ino***

How often to these snakes breed, where to they lay their eggs, and how many do they lay? I've not seen any babies; just large, mature snakes.

They give birth to live young, if I'm not mistaken. I'm not sure how often they breed though.

~Ino***