Them!

Can be heard four times in the film. When the giant ants attack the crew of the ship at sea, when James Whitmore's character Police Sgt. Ben Peterson is throttled to death by a giant ant, when a soldier is struck by the falling debris in the sewer and when James Arness gets separated from the rest of the Army and ants try to attack him. The ceiling falls in and while he reloading his weapon, an ant tries to attack him. There's also a scream off-screen from Peterson's partner, Ed Blackburn when he investigates the sounds made by the ants.