What Should You Do If You Spot a Poisonous Snake?

March 28, 2011— -- It's the kind of news that sends snake-fearing city dwellers into a hiss-obsessed frenzy: a poisonous Egyptian cobra disappeared from New York's Bronx zoo over the weekend.

And despite assurances from zoo officials that the snake is likely contained, some local residents were left worrying what to do if they encounter the deadly cobra.

In a statement this weekend, the Bronx Zoo said that it closed its Reptile House after the snake vanished.

"After learning the snake was missing yesterday afternoon, we immediately closed and secured the building as we took steps throughout the evening to recover the snake. Based on our knowledge of the natural history and behavior of snakes, we know they seek closed-in spaces and are not comfortable in open areas," the zoo said.

Zoo officials did not immediately respond to a request for comment from ABCNews.com, but in its statement the zoo said it's confident that that the 20-inch-long adolescent snake is contained in a non-public area inside the Reptile House.

Still, should spooked New Yorkers worry about a deadly snake crossing their paths?

In the case of this escaped cobra, exotic animals expert Tim Harrison said the risks are low, especially considering the cold climate. He said the cold-blooded snake is going to stay hidden inside the building.

"He's a tropical snake," Harrison said of the cobra some New Yorkers have started calling "Cobra-dini." "He's not going to get loose in New York. There's no way."

During warmer times of the year, it's possible that the animal might get more adventurous, he said, but even then it would most probably stay hidden and out of the way of busy sidewalks and crowds of people.

In the unlikely event that a person encounters the cobra, the snake would likely spread its hood as a warning before attacking, he said, adding that if you see that hood flare, you should immediately back away.

"A cobra will not, usually, ever strike puffed up," he said. "That's a warning."

Exotic Snakes Increasingly Pose Threat, Expert Says

After moving away from the snake, people should call police or other wildlife authorities, said Harrison, who is one of the central characters in "Elephant in the Living Room," the upcoming documentary about the threats of exotic animals.

If you do feel extra brave and want to cover the animal with a basket or garbage can, Harrison said to be extra careful. While cobras will likely not attack if you get out of their way, they may get aggressive if they feel threatened.

He also said that while cobras give potential prey warning, other kinds of snakes are known to attack with little advance notice.

Green and Black Mamba snakes, which can grow to 12 feet long and are indigenous to Africa, don't have any intimidating markings, but they are considered among the fastest and most dangerous snakes in the world, he said. While the snakes are not native to the U.S., they are increasingly a domestic threat as snake enthusiasts import them into the country, he said.

"They'll come after people and they don't give any warning whatsoever," Harrison said.

North American Copperhead snakes also attack with little notice, he said.

In those cases, Harrison warned, people should move away from the animal very slowly.

"Just like the snake charmers, everything nice and relaxed and smooth motions," he said. "Do not frighten the animal. If you don't frighten it, you're in good shape."