Ancestral rhinoceroses first diverged from other perissodactyls in the Early Eocene.
Mitochondrial DNA comparison suggests the ancestors of modern rhinos split from the ancestors of Equidae around 50 million years ago.
The extant family, the Rhinocerotidae, first appeared in the Late Eocene in Eurasia, and the ancestors of the extant rhino species dispersed from Asia beginning in the Miocene.

The Sumatran rhinoceros is considered the least derived of the extant species, as it shares more traits with its Miocene ancestors.
Paleontological evidence in the fossil record dates the genus Dicerorhinus to the Early Miocene, 23–16 million years ago.
Many fossils have been classified as members of Dicerorhinus, but no other recent species are in the genus.
Molecular dating suggests the split of Dicerorhinus from the four other extant species as far back as 25.9 ± 1.9 million years.
Three hypotheses have been proposed for the relationship between the Sumatran rhinoceros and the other living species.
One hypothesis suggests the Sumatran rhinoceros is closely related to the black and white rhinos in Africa, evidenced by the species having two horns, instead of one.
Other taxonomists regard the Sumatran rhinoceros as a sister taxon of the Indian and Javan rhinoceros because their ranges overlap so closely.
A third hypothesis, based on more recent analyses, however, suggests that the two African rhinos, the two Asian rhinos, and the Sumatran rhinoceros represent three essentially separate lineages that split around 25.9 million years ago; which group diverged first remains unclear.
Recent studies suggest that many specimens attributed to Dicerorhinus from the Pleistocene of China actually belong to Stephanorhinus, a closely related genus.
The earliest fossil record of the species is from the Early Pleistocene Liucheng Gigantopithecus Cave in Guangxi, China, which consists of a nearly complete mandible with preserved cheek teeth and various isolated teeth.

Because of morphological similarities, the Sumatran rhinoceros is believed to be closely related to the extinct woolly rhinoceros (Coelodonta antiquitatis) and Stephanorhinus.
The woolly rhinoceros, so named for the coat of hair it shares with the Sumatran rhinoceros, first appeared in China; by the Upper Pleistocene, it ranged across the Eurasian continent from Korea to Spain.
The woolly rhinoceros survived the last Ice Age, but, like the woolly mammoth, most or all became extinct around 10,000 years ago.
Stephanorhinus species are well known in Europe from the Late Pliocene through the Pleistocene, and China from the Pleistocene, with two species, Merck's rhinoceros and the narrow-nosed rhinoceros surviving into the last glacial period.
Although some morphological studies questioned the relationship, recent molecular analysis has supported the close relationship.

Pairwise Sequential Markovian Coalescent (PSMC) analysis of a complete nuclear genome of a Sumatran specimen suggested strong fluctuations in population size, with a general trend of decline over the course of the Middle to Late Pleistocene with an estimated peak effective population size of 57,800 individuals 950,000 years ago, declining to around 500–1,300 individuals at the start of the Holocene, with a slight rebound during the Eemian Interglacial.
This was likely due to climate change causing limiting suitable habitat for the Rhinoceros, causing severe population fluctuations as well as population fragmentation due to the flooding of Sundaland.
Human induced habitat change and hunting may have played a role in the Late Pleistocene.
The study was later criticised for not including DNA from extinct mainland populations, which would have provided a holistic account.
A Bayesian skyline plot of complete Mitochondrial genomes from multiple individuals from across the range of the species suggested that the population had been relatively stable with an effective population size of 40,000 individuals over the last 400,000 years, with a sharp decline starting around 25,000 years ago.
Ancestral rhinoceroses first diverged from other perissodactyls in the Early Eocene. Mitochondrial DNA comparison suggests the ancestors of modern rhinos split from the ancestors of Equidae around 50 million years ago. The extant family, the Rhinocerotidae, first appeared in the Late Eocene in Eurasia, and the ancestors of the extant rhino species dispersed from Asia beginning in the Miocene.
The Sumatran rhinoceros is considered the least derived of the extant species, as it shares more traits with its Miocene ancestors. Paleontological evidence in the fossil record dates the genus Dicerorhinus to the Early Miocene, 23–16 million years ago. Many fossils have been classified as members of Dicerorhinus, but no other recent species are in the genus. Molecular dating suggests the split of Dicerorhinus from the four other extant species as far back as 25.9 ± 1.9 million years. Three hypotheses have been proposed for the relationship between the Sumatran rhinoceros and the other living species. One hypothesis suggests the Sumatran rhinoceros is closely related to the black and white rhinos in Africa, evidenced by the species having two horns, instead of one. Other taxonomists regard the Sumatran rhinoceros as a sister taxon of the Indian and Javan rhinoceros because their ranges overlap so closely. A third hypothesis, based on more recent analyses, however, suggests that the two African rhinos, the two Asian rhinos, and the Sumatran rhinoceros represent three essentially separate lineages that split around 25.9 million years ago; which group diverged first remains unclear. Recent studies suggest that many specimens attributed to Dicerorhinus from the Pleistocene of China actually belong to Stephanorhinus, a closely related genus. The earliest fossil record of the species is from the Early Pleistocene Liucheng Gigantopithecus Cave in Guangxi, China, which consists of a nearly complete mandible with preserved cheek teeth and various isolated teeth.
Because of morphological similarities, the Sumatran rhinoceros is believed to be closely related to the extinct woolly rhinoceros (Coelodonta antiquitatis) and Stephanorhinus. The woolly rhinoceros, so named for the coat of hair it shares with the Sumatran rhinoceros, first appeared in China; by the Upper Pleistocene, it ranged across the Eurasian continent from Korea to Spain. The woolly rhinoceros survived the last Ice Age, but, like the woolly mammoth, most or all became extinct around 10,000 years ago. Stephanorhinus species are well known in Europe from the Late Pliocene through the Pleistocene, and China from the Pleistocene, with two species, Merck's rhinoceros and the narrow-nosed rhinoceros surviving into the last glacial period. Although some morphological studies questioned the relationship, recent molecular analysis has supported the close relationship.
Pairwise Sequential Markovian Coalescent (PSMC) analysis of a complete nuclear genome of a Sumatran specimen suggested strong fluctuations in population size, with a general trend of decline over the course of the Middle to Late Pleistocene with an estimated peak effective population size of 57,800 individuals 950,000 years ago, declining to around 500–1,300 individuals at the start of the Holocene, with a slight rebound during the Eemian Interglacial. This was likely due to climate change causing limiting suitable habitat for the Rhinoceros, causing severe population fluctuations as well as population fragmentation due to the flooding of Sundaland. Human induced habitat change and hunting may have played a role in the Late Pleistocene. The study was later criticised for not including DNA from extinct mainland populations, which would have provided a holistic account. A Bayesian skyline plot of complete Mitochondrial genomes from multiple individuals from across the range of the species suggested that the population had been relatively stable with an effective population size of 40,000 individuals over the last 400,000 years, with a sharp decline starting around 25,000 years ago.
Sumatran rhinoceros