In the novel, Kala is a female in a band of Mangani, a fictional species of Great Ape intermediate between real life chimpanzees and gorillas. She saves the infant Tarzan from the murderous fury of Kerchak, the mad leader of the ape band, after the latter kills Tarzan's human father. Kala goes on to rear the human baby as her own while protecting him against Kerchak and her own mate, Tublat. After Tarzan reaches adulthood, Kala is killed by a native African hunter, who is afterward killed by Tarzan in revenge.
Kala also appears in Jungle Tales of Tarzan, the sixth book of the Tarzan series, which relates episodes from the ape man's youth omitted from Tarzan of the Apes. Chapter 7, "The End of Bukawai," relates an episode in which Tarzan is almost killed when he swings so long on the rope that it frays and parts, dropping him to the ground. Kala runs to the boy's aid and he soon revives.
In Disney's Tarzan (1999) and its direct-to-video sequel, Burroughs's "Great Apes" are gorillas, and Kala is the mate of Kerchak (a much more benign figure in the film) rather than Tublat, who himself appears in the Disney animated TV series as the rogue tyrant instead. In the film's retelling Tarzan's parents are killed by Sabor the leopard, and Kala saves the infant Tarzan from Sabor, not Kerchak, though Kerchak disapproves of this after their biological child died at the hands of the leopard. She does not die in the movie. Kala was voiced by actress Glenn Close.