About 23 million years ago, a species of rhinoceros - similar in size to the modern Indian rhino but lacking a horn - made its home in the challenging environment of the Canadian High Arctic, which at the time was warmer than it is now but still experienced snow and months of wintertime darkness.
Fossils of the polar rhino, named Epiatheracerium itjilik, were found on Devon Island, a landscape underlain by permafrost, in Canada's Arctic archipelago. With about 75 percent of its skeleton intact, scientists gained a good understanding of the animal. Its remains were discovered in Haughton Crater, one of Earth's northernmost impact craters, about 14 miles (23 km) wide.
The polar rhino lived early in the Miocene epoch, a time of diversification of many mammalian groups. Until this discovery, no rhinoceros was known to have lived in such a high latitude. The fossil site is in Nunavut, Canada's northernmost territory.
About three feet (one metre) tall at the shoulder, this species approximated the size of the modern Indian rhinoceros, and was smaller than modern African rhinos.
"Devon Island during the Miocene was much more temperate and forested, quite unlike the polar desert that is there today," said Danielle Fraser, head of palaeobiology at the Canadian Museum of Nature in Ottawa and lead author of the study published on Tuesday in the journal Nature Ecology and Evolution.