The Tribe of Gum, (PROSE: Venusian Lullaby, COMIC: Hunters of the Burning Stone) also known simply as the Tribe, (PROSE: Doctor Who and an Unearthly Child) was a tribe of Caucasian, cave-dwelling humans that lived on Earth (TV: An Unearthly Child) in circa 100,000 BC (PROSE: The Eight Doctors) and worshipped a sun god called Orb.
They once encountered the First Doctor, Susan, Barbara Wright and Ian Chesterton, who taught them to make fire and to show compassion to one and other, though in spite of this, they were held as prisoners for the majority of their stay with the tribe, before their eventual escape. (TV: An Unearthly Child)
The tribe lived in a warm, dry cave system on Earth. The caves were located in the foothills of a range of jagged mountains, which surrounded a rocky plain. A river ran through the plain, and on both sides stood a dense, impenetrable forest, where fruits and berries grew. (PROSE: Doctor Who and an Unearthly Child)
Gor was the leader of the tribe until his death, when he was succeeded by his son Za. Za's mother was known only as Old Mother. Another member of the tribe was an elder named Horg. He was once a great leader, before he got too old. Due to his high status, his daughter Hur was the most prized woman in the tribe, and would be given only to the tribe leader. Kal was a short lived member of the tribe who was the only survivor of his own tribe before being adopted into the Tribe of Gum. (TV: An Unearthly Child, PROSE: Doctor Who and an Unearthly Child) Kagg was also a member by the year 2013. (COMIC: Hunters of the Burning Stone)
One of the tribe's favoured policies was that leadership was given to the one who was able to make fire. Therefore this ability was a closely guarded secret, and passed only from father to son. (TV: An Unearthly Child) The secret wasn't passed down to the children all too quickly either, as even a son could become a rival, especially with the secret of fire. (PROSE: Doctor Who and an Unearthly Child)
The last firemaker, Gor led the tribe for a time, until he was killed in a hunting accident. Dying before he taught the secret of firemaking to his son Za, the tribe was freezing during the winter and unable to cook their food, which included tiger and bear. Some of the tribal elders however shunned fire altogether, with one woman stating, "There were leaders before there was fire; fire will kill us all in the end."
Kal joined the tribe after his own tribe died during a time of cold. (TV: An Unearthly Child) As he was the best hunter - never returning from a hunt empty-handed - he quickly won the acceptance of the tribe. (PROSE: Doctor Who and an Unearthly Child)
Za wanted to take what he saw as his rightful place as the leader of Gum, but without the ability to make fire, the others would not wholeheartedly follow him. Some of the people, however, thought Kal had a better chance of making fire than Za, and so wanted to follow him instead. Naturally, a struggle for power broke out between the two of them.
One day, near the height of this power struggle, Kal was out roaming the plains and came across the First Doctor, who produced fire with matches. He seized this opportunity to knock the Doctor unconscious and haul him back to the tribal caves.
Meanwhile, the Doctor's companions Susan, Barbara and Ian had realised he was missing and were out searching for him. But they too were captured by the tribe and brought to the same cave. The Doctor woke up and offered to make fire for the tribe if they took him back to the TARDIS, where he had left spare matches, but the tribe were so involved in their power struggle that they were unable to listen. During an argument, some of the tribe were going to kill the companions on the spot, but Za prevented this, proclaiming that Orb would wish to see them. He believed that if they waited to sacrifice the quartet when Orb next appeared in the sky, then Orb would grant them fire. Thus the prisoners were taken to await their fate in the Cave of Skulls.
An elder woman, fearing fire, set the captives free in the night. Za and Hur followed them into the Forest of Fear in order to get their secrets of fire. Za was attacked by a beast. The companions nursed him back to health, and the pair were puzzled at this caring behaviour, as killing rivals was the norm in those primitive times. Meanwhile Kal killed the old woman and blamed Za. Led by Kal, the tribe caught up with the delayed travellers. Kal confronted Za, but the Doctor was instrumental in turning the tribe against Kal by tricking him into showing his blood-stained knife, and they drove him away. The tribe, now led by Za, recaptured the companions and took them back to the Cave of Skulls.
Za took this opportunity to learn the fire secrets from them. In the midst of this Kal returned, killed the guard at the Cave of Skulls, snuck in and challenged Za. They fought to the death with Za emerging as victor. With Kal dead, and the knowledge of fire in his possession, Za emerged from the cave as the undisputed leader of Gum. Za insisted on a union between Gum and the new tribe of the companions, and would not hear otherwise. The companions thus used their cunning to frighten the tribe and escape back to the TARDIS.
An alien race known as the Prometheans witnessed this brief encounter, and decided to continue what they had seen as an abandoned social experiment by giving the tribe psychic metal, which granted them god-like powers and allowed them to travel to the stars in search of more metal, as well as the teachers which had left them before.
The Tribe caught up with Ian, Barbara and the Eleventh Doctor in the year 2013 where, after a Promethean neural reverted to humanity to a stone age mentality, encouraged their fellow man to worship the Prometheans. When the Doctor reversed this, the Tribe sought to attack him only for Ian and Barbara to come to his defence, speaking of the great good that the Doctor had done for Earth. Convinced, the Tribe of Gum turned on the Prometheans, both sides destroying each other in the struggle. (COMIC: Hunters of the Burning Stone)
Behind the scenes
The name "Tribe of Gum" originates from earlier drafts of the serial which would become An Unearthly Child, in which prospective tribe leader Kal was named Gum. The name is not used in the serial as broadcast, though it is well attested to in other media, in passing in the 1994 Virgin Missing Adventures novel Venusian Lullaby, and then most prominently in 2013's DWM comic story Hunters of the Burning Stone, which set them at the centre of its 50th anniversary narrative.