I don't know, but call the zoo. Bet they can tell you.

In my co we call animal control. If not avail, some pest control cos will do it

eta: my guess is the snake is long gone as dogs started barking etc, they sense danger and flee. I am terrified of snakes btw

In most incorporated areas that actually have an Animal Control Department, that's where you start. If AC doesn't deal with venomous snakes in your area, you can call the local police department or sherriff's office, depending on whose jurisdiction you live in. Some of them do not respond on venomous snake calls, some do. If you cannot get any help that way, check the Yellow Pages for pest control companies for someone like this one that I found by Goggling:

Wildlife and Pest Control/Removal

Where we live, in an unincorporated part of a rural county, the only Animal Control officer in the county is employed by the city of Marietta, so that employee only responds to animal complaints within the city limits. Out here in the rural areas, we have to deal with them ourselves, which is not a problem since you can shoot guns in unincorporated areas. In some of the smaller towns, like Thackerville, the local police sometimes respond to help a citizen who has a problem with dogs at large or wildlife issues.

Good luck. My experience with snakes is that if you don't kill it or trap it when you see it, then it will be gone when you fetch a gun and come back 3 or 5 minutes later. They don't just sit there waiting for you to come back. To get around that when I am home alone, I just call the nearest neighbor who is home and they come over and shoot the varmint, which I have been standing and watching so it can't get away or go into hiding before they get there. Good neighbors like that are worth their weight in gold.

We're in the city limits but we kill our own varmints and snakes.

My husband took care of it, but I am going to contact the city to see why I could not get more help. The city could charge us, especially for a false call, but poisonous is serious to everyone.

Depending on where you live, the question might be where did it come from. We had a manhole for a storm drain in our back yard in Tulsa. If you find there's a route into your yard, you MIGHT get more help. Here is a link on Snake Removal. I was interested in the trap.

We moved here in 1979. Our housing addition was new because it was near the green belt that was built for flood protection. A creek behind our house is an invitation to snakes and almost all critters to visit us. This is the first water moccasin. Since my husband killed it, we saw up close that it was what we thought it was.

I hope it did not have a family that would look for it.

Sammy

Yeah, I have a drainage ditch next to the house here in Owasso. We watched some kind of snake doing what we could only assume was a mating dance in that water. Someone told DH that geese killed snakes, so we got a pair of white domestic geese. Did they kill snakes? IDK. But I always figured they would make a lot of noise if they saw a big one (they were good "watch" geese). I think they would have eaten baby snakes. They are mostly grazers, but kind of opportunistic when it comes to food. The goose would climb over any barrier to get to dog food and we had to fence the patio because I got tired of it being slimed with goose poop. The kids enjoyed them. They attracted ducks and a rabbit that adopted us. They hatched a dozen gosslings one year, who went to live in the country. Another chapter in our managerie.