There are only two puff adders in the world...the African and the Somali. Both extremely venomous....this is a picture of one...
Possibilities for what you saw....
#1: Bull Snake...found all throughout North American especially from the mississippi west...Oklahoma is loaded with them...non-venomous constrictor that acts like a rattler when threatened. Not prevalent for "flattening" or "puffing" the head however.
a picture of one:
Info on them:
Diet:
Bull snakes eat small mammals, such as rabbits, gophers, rodents, as well as ground nesting birds, lizards, and the young of other snakes. Juvenile bull snakes depend on insects and small lizards.
(The idea that bull snakes occasionally eat rattlesnakes is sometimes touted as a reason for humans not to harm bull snakes when encountering them in the wild, although a better reason is the bull snake's role in controlling warm-blooded vermin such as rodents. Note that many snakes have evolved a natural immunity to venom, just as rattlesnakes themselves are immune to their own.)
Behavior:
Most bull snakes are quite docile, and can easily be handled with open hands, or worn as bracelets or necklaces. In contrast, some bull snakes are quite bad-tempered, and if captured or cornered will bite anyone who comes near.
When threatened by anything as large as a human, a bull snake's primary defense is to flee, if possible.
As another defense mechanism, bull snakes mimic rattlesnakes. This starts with coloration, which generally follows the "diamondback" pattern. When angry or threatened, bull snakes often will elevate their tail and rapidly vibrate it, the way a rattler would. They also hiss, making a rattle-like sound. All in all, this can be convincing to someone not familiar with the details. If cornered, they assume a rattlesnake-like coiled posture, from which they can lunge far and fast to bite an opponent. The long, thin teeth are unlikely to do lasting damage to humans.
They customarily kill their prey by constriction before eating it.
#2: Western Hognose (Heterodon)...this is the most likely candidate for what you saw.
A pic of one: (The colors can vary from whiteish, yellowish, brown, black and even reddish markings.)
Some info on it.
Hognose snakes are rear-fanged and technically venomous, but the venom they excrete is not considered to be dangerous to humans and they will never bite in defense (as the only way to get bitten by a hognose snake is to smell like their prey). There has been some debate whether or not hognose are venomous, but there is evidence that their saliva has some toxicity to smaller prey items, such as toads and frogs.
Behavior:
When threatened, hognose snakes will flatten their necks and raise their heads off the ground, not unlike a cobra, and hiss. They may sometimes feign strikes, but are not apt to bite. This behaviour has earned them several nicknames, such as "puff adder", "blowing adder", "flathead", "spreading adder" or "hissing adder". Note, though, the nickname "puff adder" is only a nickname, and is not scientifically correct. There is a highly venomous viper from Africa called the puff adder, Bitis arietans. pictured top of post.
If this threat display does not work to deter a would-be predator, hognose snakes will often roll onto their back and play dead, going so far as to emit a foul musk and fecal matter from their cloaca and let their tongue hang out of their mouth, sometimes accompanied by small droplets of blood. If they are rolled upright while in this state, they will often roll back as if insisting they really are dead. It has been observed that the snake, while appearing to be dead, will still watch the animal that caused the death pose. The snake will 'resurrect' sooner if the threat is looking away from it than if the threat is looking at the snake.
Diet:
Heterodon are diurnal active foragers that typically consume their prey live without any constriction or body pinning.
For most hog nose snakes the bulk of their diet is made up by rodents, and lizards. H. platyrhinos is an exception, and specializes in feeding on toads although other food items such as eggs, insects and mice can make up as much as 50% of their diet.
Good luck with this. I would move mama and eggs for sure. Check out the snake and see if you want it around...sometimes having a particular snake around is a blessing.
example: I have a kingsnake about 6' long that suns in my yard. I allow him to stay around because (unlike the lady across the street from me) I do not have rattlesnakes in my yard.
I will let the kingsnake stay and eat all the rattlesnakes he wants.
I candled about 10 out of about 15 of her eggs and all of them showed a chick moving about!!
