A venomous, tree-climbing 3-foot mangrove snake escaped its enclosure at a Bronx Zoo in New York on Tuesday. Officials said the reptile was on the loose.

“Dear visitors, a 3 and a half foot long mangrove snake is missing from its exhibit in Jungle World. They are mildly venomous, but not dangerous to people," a sign placed next to the ticket office for Jungle World on Wednesday read. “Mangrove snakes are a shy, arboreal species that are active at night. There is little chance of seeing or coming in contact with this snake due to its timid, secretive nature but if you see it, please notify a staff person.”

According to the Smithsonian’s National Zoo & Conservation Biology Institute, there have been no known mangrove snake fatalities. However, the venom of these snakes can cause painful swelling and discoloration of the skin.

The New York Post reported that not many people noticed the small sign while entering the exhibit. Zoo-goers said they wouldn’t have gone in if they knew a snake was on the loose inside.

“It’s irresponsible of them,” Lucia Crespo, 29, a teacher who was visiting with her young son, said. “It’s scary and I have a 3-year-old son. Now I’m feeling terrified … I don’t like snakes at all.”

Engelbert Balboa, 33, another zoo-goer, said he was terrified.

“I’m scared. It can bite you, it can harm you. I wouldn’t go in there if I knew,” he said. “To think I went in there with my son and my mother and my sister.”

Two zoo employees with flashlights scoured the area near where the snake went missing Wednesday. It remains unclear how the snake escaped.

This is not the first time the Bronx Zoo has lost a snake. A deadly Egyptian Cobra escaped in 2011 and was on the loose for a week before being found.

Mangrove snakes are nocturnal snakes native to southeast Asia and eat small mammals. They also feed on reptiles including lizards and other snakes.

This is a picture of a boa constrictor at the El Salvador National Zoo in San Salvador, June 15, 2017. Getty Images/Oscar Rivera