Mountain gorillas are descendants of ancestral monkeys and apes found in Africa and Arabia during the start of the Oligocene epoch (34–24 million years ago). The fossil record provides evidence of the hominoid primates (apes) found in east Africa approximately 22–32 million years ago. The fossil record of the area where mountain gorillas live is particularly poor and so its evolutionary history is not clear.[5] It was about 8.8 to 12 million years ago that the group of primates who were to evolve into gorillas split from their common ancestor with humans and chimps; this is when the genus Gorilla emerged. Mountain gorillas have been isolated from eastern lowland gorillas for approximately 10,000 years and these two taxa separated from their western counterparts approximately 1.2 to 3 million years ago.[6] The genus was first referenced as Troglodytes in 1847, but renamed to Gorilla in 1852. It was not until 1967 that the taxonomist Colin Groves proposed that all gorillas be regarded as one species (Gorilla gorilla) with three subspecies Gorilla gorilla gorilla (western lowland gorilla), Gorilla gorilla graueri (lowland gorillas found west of the Virungas) and Gorilla gorilla beringei (mountain gorillas, including Gorilla beringei, found in the Virungas and Bwindi). In 2003, after a review, they were divided into two species (Gorilla gorilla and Gorilla beringei) by The World Conservation Union (IUCN).[5] There is now agreement that there are two species, each with two subspecies.[7] Be sure to use code: HERDSODA at drinkolipop.com and save 15% on all orders!