In the 1976 film adaptation of the book, the Sagoth are servants of the Mahar, used to capture Gilak slaves to toil in the Mahar City or be eaten by the voracious creatures. It is clearly evident that the Mahars exert tremendous mental control over the Sagoth, making them, in a very real sense, slaves as well. One Sagoth, on the verge of death, was compelled by the Mahars to crawl over to attack Ra in a failed attempt to stop the human from altering the lava flow into the city. It is unclear if the Sagoth have a society independant of the Mahar, or if they were able to survive their masters' apparent extinction.
In the film, the Sagoth speak in garbled, almost metallic voices, and their eyes glow blue-green when under direct Mahar mental domination.