Paraceratherium is an extinct genus of hornless rhinoceros. It is one of the largest terrestrial mammals that has existed and lived from the early to late Oligocene epoch. The first fossils were discovered in what is now Pakistan, and remains have been found across Eurasia between China and the Balkans.
The exact size of Paraceratherium is unknown because of the incompleteness of the fossils. Some estimate that it had a shoulder height around 4.8 metres (15.7 feet), and a length of about 7.4 metres (24.3 feet). Its weight is estimated to have been about 15 to 20 tonnes (33,000 - 44,000lbs/ 13,607 - 18,144kg). The long neck supported a skull that was about 1.3 metres (4.3 ft) long. It had a nasal incision that suggests it had a prehensile upper lip or proboscis (trunk).
The Last of the Rhinoceros Titans
Paraceratherium is an extinct genus of hornless rhinoceros that has traditionally been heralded as the largest mammal ever to tromp over the Earth. It is far larger than any rhino alive today, and was an iconic member of mammal megafaunas that roamed Eurasia between about 35 and 20 million years ago. Paleontologists are slowly working on piecing together a more complete picture of the superlative mammal.
Many names:
The taxonomy of the genus and the species within has a long and complicated history. While there are articles, books, and documentaries using names such as “Indricotherium”, “Baluchitherium”, or “Pristinotherium”, it is now believed that the list of names were created by incomplete knowledge of early finds and the idiosyncratic process of applying names to extinct animals. Most modern scientists consider these genera to be junior synonyms of Paraceratherium which means "near the hornless beast" as it has priority of place as the single valid name for all the huge fossil rhinos that roamed from eastern Europe through Mongolia during the Oligocene epoch and that all the skeletons of the biggest rhinos so far known fall within the range of variation for this single genus.
Description:
The exact size of Paraceratherium is unknown because of the incompleteness of the fossils but Paraceratherium was known to be tall with a long, deep neck and a prehensile lip which would have allowed it to feed on trees and shrubs rather than graze. Revised weight estimates have moved Paraceratherium away from often cited estimates of 30 tons towards a more modest 15-20 ton range, comparable to estimates for large mammoths and other big fossil elephants. Some like Donald Prothero have proposed that, contrary to most depictions, Paraceratherium had large elephant-like ears that it used for thermoregulation. The ears of elephants enlarge the body's surface area and are filled with blood vessels, making the dissipation of excess heat easier. According to Prothero, this would have been true for Paraceratherium, as indicated by the robust bones around the ear openings. However, other palaeontologists such as Pierre-Olivier Antoine and Darren Naish have expressed scepticism towards this idea. There are no indications of the colour and skin texture of Paraceratherium because no skin impressions or mummies are known. Most life restorations show the creature's skin as thick, folded, grey, and hairless, based on modern rhinoceroses.
Theories on their cause of extinction:
Reviewing the relatively small literature on the natural history of Paraceratherium, there are many theories as to why the large rhino is thought to have gone extinct. One of them is that their simple, low-crowned teeth indicated that Paraceratherium was a high browser with a diet consisting of relatively soft tree leaves and shrubs. Later rhinoceroses were grazers, with high-crowned teeth because their diets contained grit that quickly wore down their teeth. It is though that when archaic elephants moved into Paraceratherium habitat, they changed the landscape by stripping and pushing over the trees that these huge rhinos relied on. This triggered ecological changes that caused their food source to become scarce, and along with a low birth rate, potential climate change, and threats from large predators like Hyainailurus and Amphicyon who arrived in Asia around the early Miocene, sealed their fate and pushed them into extinction.
