The film gathers its several characters from different parts of the world: Sean Mercer (John Wayne), Pockets (Red Buttons), Anna Maria 'Dallas' D'Allesandro (Elsa Martinelli), Kurt Mueller (Hardy Krüger), Brandy De la Court (Michele Girardon), Charles 'Chips' Maurey (Gerard Blain), Luis Francisco Garcia Lopez (Valentin De Vargas) are, respectively, from USA, Italy, Germany, France, France and Mexico.
The plot involves a group of Western expatriates catching wild animals in Africa and selling them to zoos. Lead by Mercer after the character Little Wolf aka 'The Indian' (Bruce Cabot) is injured during a chase, the international group try to fill all the orders for the season. A wildlife photographer (Elsa Martinelli) arrives to take photos of the captures for the zoo which will be buying the bulk of that season's captures. She is first mistaken for a man because of the introduction letter she'd signed with only her initials. Due to the complexity of her name she is nicknamed 'Dallas'. During her stay she becomes known as Momma Tembo (Mother of Elephants) for her efforts to save three baby elephants, culminating in a chase through the streets of Arusha in Tanzania. She also developes a crush on Mercer. There are romantic subplots between the other characters as well. Hatari! has a very loose script and, like many other major works of Hawks, is principally structured on the relationships between the (non-African) characters. Much of the film centers around scenes of chasing animals in jeeps and trucks across the African plains. The chased animals are also all live, wild, and untrained, a procedure banned today over concerns of exhausting and killing the targeted animals. The script was written by Hawks' favorite writer, Leigh Brackett, after the group returned from Africa with the hunting scenes. Some consider that Hatari! belongs among her better works, like Rio Bravo and Red River.
As the animals frequently refused to make noise 'on cue' (in particular, the baby elephants refused to trumpet inside populated areas), local Arusha game experts and zoo collectors were hired to do 'animal voice impersonations'.
Hawks has stated in interviews that he had originally planned to star both Clark Gable and Wayne in the film until Gable's death two years before the film was finally produced ruled that out.
Hatari! introduced the memorable Henry Mancini tune "Baby Elephant Walk". Other memorable musical moments involve a duet of Stephen Foster's Old Folks at Home (Swanee River) with Martinelli's character playing the piano, and Red Buttons' character playing the harmonica. Also, after 'the Indian' is left to recuperate in the hospital, the members of the group get drunk and sing a somewhat tragicomical song that features lyrics like "Oh whisky leave me alone, I'm tired and I want to go home".