Officials at the Bronx Zoo say a 3 1/2-foot-long mangrove snake has gone missing, but say there�s no threat to visitors.

The zoo says the mildly venomous snake wasn�t in its exhibition at the end of the day Tuesday, and hasn�t been seen since.

A notice warning visitors was put up on Wednesday, although the zoo says it�s confident there�s no threat and mangrove snakes are not known to be dangerous to people.

The zoo says the snakes are shy and timid, and active at night.

(AP)