While they’re not the enormous size they were in the movie, and they certainly can’t devour a healthy human being in a matter of seconds, they are pretty scary. From the Dorylus page at Wikipedia (the proper name of the ants):
Seasonally, when food supplies become short, they leave the hill and form marching columns of up to 50,000,000 ants which are considered a menace to people, though they can be easily avoided; a column can only travel about 20 meters in an hour. It is for those unable to move, or when the columns pass through homes, that there is the greatest risk. There have been reported cases of people – usually the young, infirm, or otherwise debilitated who could not escape – being killed and eventually consumed by them, often dying of asphyxiation.
This last sentence should be taken with a grain of salt, as it lacks a proper citation on Wikipedia. They are, however, pretty impressive. While they’re not nearly as large or fast-moving as they are in the movie, the picture on the left is a swarm of them eating a grasshopper, and they’re pretty big as far as ants go.
They’re actually not called Dorylus the Dorylus Genus of Army Ants is common to Africa and Asia, their smaller size is due to competition for food with Termites which are more prevalent on both continents. In fact the South American verity are of the Genus Eciton the most well known of which is the Eciton burchellii commonly know as “The Army Ant” they are known to consume full size hunting animals i.e. Deer, in 6 minutes. The Eciton Genus is larger than the Dorylus Genus and the huge size portrayed in the Indiana Jones film is appropriate, though as the species is polymorphic the ants do vary in size from 3-12 mm in length. The Eciton burchellii is the only known ant species to have been observed using their bodies to block potholes and pitfalls in the path of their travel. Individuals will move into the holes and measure to see if they can fit the gap, if they are unable to do so they will move on and another will attempt. The so-called “Bridge” ants can remain in place for hours at a time and will usually return to the nest after traffic slows or it becomes dark.