Physically very like humans, they had jutting brow ridges, large noses and stooped postures. However, while stereotyped as brutish by later humans, Nimrod showed intelligence and spoke articulately. (TV: Ghost Light)
The tribe which Nimrod originally belonged to herded mammoths during the summer for food. They considered the fang of the cave bear to be a sign of wisdom. The tribal elders "spoke with the voice of the Burning One", namely Light. The actions of the Seventh Doctor implied that at some time in the past, the Doctor had encountered the Neanderthal species some time before. (TV: Ghost Light)
- Nimrod referred to Light as "The Burning One", implying that his tribe worshiped him. Alternatively, they may have originally worshiped another deity (or the Sun) as the Burning One and when Light appeared, transferred their worship to him.
Neanderthals evolved in Eurasia around the same time as humans did in Africa, from the same ancestor species. The Neanderthals were mostly wiped out by the Humans, with the help of the Dæmons, who for unknown reasons favoured Humanity. (TV: The Dæmons) They were believed to be wiped out around 26,000 BC. (PROSE: Only Human)
Nimrod was preserved as the last specimen of his species as part of the Catalogue of Life by the alien survey team headed by Light. In 1883, Josiah Samuel Smith awoke him and employed him as his butler. (TV: Ghost Light)