A nest of gigantic irradiated ants is discovered in the New Mexico desert; they quickly become a national threat when it is discovered that two young queen ants and her consorts have escaped to establish new nests. The national search that follows finally culminates in a battle with Them in the concrete spillways and sewers of Los Angeles.
New Mexico State Police Sgt. Ben Peterson and Trooper Ed Blackburn discover a little girl wandering the desert in a state of shock near Alamogordo. They take her to a nearby recreational trailer, located by a pilot in an airplane, where they find evidence that the little girl had been in the trailer when it was viciously attacked and nearly destroyed by someone or something. Later, it is discovered that the trailer was owned by an FBI Special Agent named Ellinson who was on an extended vacation with his wife, son, and daughter. None of the other members of the girl's family can be found at the trailer site. While being placed in an ambulance to take her to a hospital for treatment of her catatonic state so that she may be questioned about what happened to her family, the child briefly reacts to a strange, pulsating high-pitched sound by sitting up on the stretcher. The other characters in that scene do not notice her reaction, and when the noise stops, the girl lays back on the stretcher, once again unseen.
General store owner "Gramps" Johnson is found dead, a wall of his store having been partially torn out. After a quick investigation, Sgt. Peterson leaves trooper Blackburn behind to secure the scene. Blackburn later goes outside to investigate a strange, pulsating sound; gun shots are fired, the sound grows faster and louder, and Blackburn's scream is heard.
Peterson's boss in New Mexico points out that Gramps had time to fire all his ammunition, and Trooper Blackburn was a "crack shot", eliminating the possibility of a homicidal maniac. More puzzling is the coroner's report on Johnson's death: he died from a broken neck, back, skull fracture, crushed abdomen, and "enough formic acid in his body to kill 20 men".
The FBI assigns Special Agent Robert Graham to New Mexico to investigate. After having analyzed a strange print found near the Ellisons' RV, the Department of Agriculture sends myrmecologists Dr. Harold Medford and his daughter, Dr. Pat Medford, to assist in the investigation. The elder Medford exposes the Ellinson girl to formic acid fumes, which revives her from her catatonic state; she screams, "Them! Them!" His suspicions are validated by her reaction, but he will not reveal his theory prematurely.
At the Ellinson campsite Pat encounters a giant, eight-foot-long foraging ant. Following instructions from the elder Medford, Peterson, and Graham shoot off the ant's antennae, blinding it; they then kill it with their Thompson submachine gun. Medford reveals his theory: a colony of giant ants, mutated by radiation from the first atomic bomb test near Alamogordo, is responsible for the killings.
Gen. O'Brien orders a helicopter search, and the skeletal remains of past victims are discovered near the ants' nest. Cyanide gas bombs are used, and Graham, Peterson, and Pat descend into the nest to kill any survivors. Deep inside, Pat finds evidence that two queen ants have hatched and have escaped to establish new colonies.
The elder Medford gives a briefing on ants to a government task force; they covertly investigate all reports of any unusual activity. One report shows a civilian pilot (Fess Parker) has been committed to a mental hospital after claiming that he was forced down by UFOs, shaped like giant ants. Next the Coast Guard receives a report of a giant queen hatching her brood in the hold of a freighter at sea in the Pacific; giant ants attack the ship's crew, and there are few survivors. The freighter is later sunk by U.S. Navy gunfire.
A third report leads Peterson, Graham, and Maj. Kibby to a large sugar theft at a rail yard in Los Angeles. An alcoholic in a hospital "drunk tank" claims he has seen giant ants outside his window. The mutilated body of a father is recovered, but his two young sons are missing. Peterson, Graham, and Kibby find evidence that they were flying a model airplane in the Los Angeles River drainage channel near the hospital. Martial law is declared in Los Angeles, and troops are assigned to find a nest in the vast storm drain network under the city.
Peterson finds the two missing boys alive, trapped near the ants' nest. He calls for reinforcements and lifts both boys to safety, just before being attacked by a giant ant. Graham arrives with reinforcements and kills the ant, as others swarm to protect the nest. Peterson dies from his injuries. Graham and the soldiers fight off the ants, but a tunnel collapse traps Graham. Several ants charge, but he is able to hold them off with his submachine gun just long enough for troops to break through the collapse. The queen and her hatchlings are discovered and quickly destroyed with flamethrowers. Dr. Medford offers a philosophic observation: "When Man entered the Atomic Age, he opened the door to a new world. What we may eventually find in that new world, nobody can predict".Leonard Nimoy has a small, uncredited part as a U.S. Army Staff Sergeant in the communications room.
Other actors who appear in small parts include John Beradino, Willis Bouchey, Booth Colman, Richard Deacon, Lawrence Dobkin, Ann Doran, William Schallert, Douglas Spencer, Dub Taylor, Dorothy Green, and Harry Wilson.
When casting his planned Davy Crockett episode of the Disneyland television show, Walt Disney viewed the film to see James Arness, who had been recommended for the role. However, Disney was more impressed by a scene with Fess Parker as an inmate in a mental ward of the Texas hospital. Watching Parker's performance, Disney realized he had found his Davy Crockett. John Wayne saw the film and, impressed with Arness' performance, recommended him for the role of Marshal Matt Dillon in the new Gunsmoke TV series, a role that Arness went on to play from 1955 to 1975.
When Them! began production in the fall of 1953, it was originally conceived to be in 3D and Warner Color. During pre-production, tests were to be shot in color and 3D. A few color tests were shot of the large-scale ant models, but when it was time to shoot the 3D test, Warner Bros.' "All Media" 3D camera rig malfunctioned and no footage could be filmed. The next day a memo was sent out that the color and 3D aspects of the production were to be scrapped; widescreen black-and-white would now be the film's presentation format. Warner Bros. hoped to emulate the "effective shock treatment" effect of its previous science-fiction thriller The Beast From 20,000 Fathoms; ultimately, however, the film was never shot in widescreen. Because of the preparation of certain scenes, many of the camera set-ups for 3D still remain in the film, like the opening titles and the flamethrowers shots aimed directly at the camera.
Although Warner Bros. was dissatisfied with the color results, the film's titles were printed in a vivid red-and-blue against a black-and-white background in order to give the film's opening a dramatic "punch". This effect was achieved by an Eastman Color section spliced into each release print. The 1985 VHS tape release, the subsequent LaserDisc and later DVD release have retained this black-and-white-with-two-color title effect.
The entrance to the ants' final nest was shot along the concrete spillways of the Los Angeles River, between the First and Seventh Street Bridges, east of downtown. The depiction of the Chihuahuan Desert of southern New Mexico is actually the Mojave Desert near Palmdale, California. Mercy Hospital was a real institution and is now Brownsville Medical Center.
James Whitmore wore "lifts" in his shoes to compensate for the height difference between himself and James Arness. It has also been noted that Whitmore employed bits of "business" (hand gestures and motions) during scenes in which he appeared in order to draw more attention to his character when not speaking.
The Wilhelm scream, created three years earlier for the film Distant Drums, is used during the action sequences: when a sailor aboard the freighter is grabbed by an ant, when James Whitmore's character is caught in an ant's mandibles, and when an overhead wooden beam falls on a soldier in the Los Angeles storm-drain sequence.
The giant ants, painted a purplish-green color, were constructed and operated by unseen technicians supervised by Ralph Ayers. During the climactic battle sequence in the Los Angeles sewers, there is a brief shot of one ant moving in the foreground with its side removed, revealing its mechanical interior. This blunder has been obscured in the DVD releases of the film.
The sounds the giant ants emit in the film were the calls of Bird-voiced tree frogs mixed in with the calls of a wood thrush, hooded warbler and red-bellied woodpecker. It was recorded at Indian Island, Georgia, on April 11, 1947 by the Cornell Lab of Ornithology.
Them! was released in June 1954 and by the end of that year had accrued $2 million (US) in distributors' domestic (U.S. and Canada) rentals, making it the year's 51st biggest earner. According to an article in The Slate, this was Warner Bros. highest-grossing film that year. However, 1954 In Film lists two other films from Warner Bros. that earned more in gross.
From contemporary reviews, the Monthly Film Bulletin stated that despite the science fiction film genre being new it had developed several sub-divisions including "the other-worldly, the primaeval-monstrous, the neo-monstrous, the planet-ary-visitant, etc." and that "Them! is a "well-built example of the neo-monstrous", "less absurdly sensational than most" Discussing the ant monsters in the film, the review referred to them as "reasonably horrible--they do not entirely avoid the impression of mock-up that is almost inevitable when over-lifesize creatures have to be constructed and moved", while noting that they were "considerably more conceivable than those prehistoric remnants that have recently been emerging from bog and iceberg". The review commented on the cast as "like most science-fiction, [the film] is on the whole serviceably rather than excitingly cast" and the crew was noted, stating the direction was "smoothly machined" and the film has "decent writing" though "more short cuts might have been [taken]", finding that the start of the film was too slow. The New York Times review noted "... from the moment James Whitmore, playing a New Mexico state trooper, discovers a six-year-old moppet wandering around the desert in a state of shock, to the time when the cause of that mental trauma is traced and destroyed, Them! is taut science fiction". The reviewer in Variety opined it was a "top-notch science fiction shocker. It has a well-plotted story, expertly directed and acted in a matter-of-fact style to rate a chiller payoff and thoroughly satisfy the fans of hackle-raising melodrama".
Since its original release, Them! has become generally regarded as one of the best science fiction films of the 1950s. Bill Warren described it as " ... tight, fast-paced and credible ... [T]he picture is suspenseful". Phil Hardy's The Aurum Film Encyclopedia: Science Fiction noted, "Directed by [Gordon] Douglas in semi-documentary fashion, Them! is one of the best American science fiction films of the fifties". Danny Peary believed the film "Ranks with The Thing and Invasion of the Body Snatchers as the best of the countless '50s science fiction films". In the Time Out Film Guide, David Pirie wrote, "By far the best of the 50s cycle of 'creature features' ... retains a good part of its power today". The review aggregator website Rotten Tomatoes reported a 100% approval rating with an average rating of 7.6/10, based on 26 reviews. The website's consensus reads, "One of the best creature features of the early atomic age, Them! features effectively menacing special effects and avoids the self-parody that would taint later monster movies".
Them! was nominated for an Oscar for its special effects and won a Golden Reel Award for best sound editing. The film has been nominated for two American Film Institute lists, AFI's 100 Years ... 100 Thrills and AFI's 10 Top 10 (science fiction genre).Van Morrison's band Them was named after this film.
New Jersey punk band the Misfits has a song titled "Them!", with lyrics directly inspired by the film, on their 1999 release Famous Monsters.
The video game series It Came From the Desert was inspired by Them!
Eight Legged Freaks features a scene in which sequences from the film are included.
The Counterstrike expansion for Westwood Studios' Command & Conquer: Red Alert had a secret four-part mini-campaign called It Came From Red Alert!; the primary antagonists are giant ants.
Lilo & Stitch 2: Stitch Has a Glitch features it on a TV that Lilo, Stitch, Nani and David watch along with Pleakley and Jumba. It was also originally that Warner Bros. did not publish the tie-in game of Disney until Cars 3: Driven to Win.
Fallout 3, which takes place in a post-apocalyptic irradiated wasteland, has a side-quest involving giant mutated fire ants titled "Those!" in homage to the film.
In Tim Burton's film Ed Wood, Bela Lugosi (Martin Landau) explains to Ed (Johnny Depp), "Nobody wants vampires anymore. Now all they want is giant bugs". The scene takes place in 1952, but the actual movie came out two years later.
In the 1950s E.C. Comics parody comic, Panic, a companion to the highly successful Mad, there is a parody on this film titled "Them! There! Those!" featuring art by Wally Wood. [ Issue # 7 ]
The 1960s Remco toy line titled "Hamilton's Invaders" featured giant bugs versus military defenders. One of the larger mechanical bugs was designed after the giant ants in Them, "The Spooky Spider", even though the creature sports only six legs. Another creature in this line also featured a giant bug designed after the giant wasps from the 1950s sci-fi feature Monster From Green Hell, called "Horrible Hamilton".
Screenwriter Neil Ruttenberg and producer Richard Donner pitched a remake in which the ants would be intelligent and terrifying. Warner Bros. decided instead upon on Bob Gale's pitch, which included mechanical effects.