Strange Primates Lived in Arctic 52 Million Years Ago

VIVA – Around 52 million years ago, two small primates scampered around in the Arctic. They use their strong jaw muscles to chew the tough vegetation that managed to survive at the gloomy northern pole, a new study finds.

The two newfound primates which belong to the already established primate genus Ignacius, and were given the new species names of I. dawsonae and I. mckennai were small, weighing in at an estimated five pounds each (2 kilograms). They are the earliest known example of primates living in the Arctic, according to a new study published on Wednesday, January 25, in the journal PLOS One.

This discovery is based on an analysis of fossilized jaws and teeth found on Ellesmere Island in Northern Canada. North of Baffin Bay, the island lies just south of the Arctic Ocean. It is about as far north as you can get in Canada.

“These are among the most tropically adapted, warm-weather loving of all mammals, so they would be the last mammals there, north of the Arctic Circle,” Study senior author, Christopher Beard stated.

The two species lived during the Eocene epoch (56 million to 33.9 million years ago), a period of intense planetary warming. At the time, there were no ice caps at the poled, and Ellesmere Island would have had a warm and muggy climate like today’s Savannah, Georgia, according to a study author, Kristen Miller.

As information, temperatures on Ellesmere Island were hospitable enough to host a diverse ecosystem of unlikely animals, including early Tapir-like-ungulates and even crocodiles, snakes, and salamanders. While Eocene arctic dwellers did not have to deal with extreme temperatures, life in the warm Arctic wasn’t without its challenges.

Because of the tilt of the Earth’s axis, the sun doesn’t rise on the island for half of the year, “We’ve got six months of winter darkness and six months of summer daylight,” Kristen Miller says, as quoted from the Live Science site.

The main challenge for animals living so far north is a lack of food. Under such conditions, vegetation is likely to be scarce during the long, dark winters, so the researchers hypothesize that Arctic animals in the Ignaceous genus likely subsisted on tough-to-chew foods, such as seeds or tree bark.

Compared to their more southerly Arctic primate relatives, their cheekbones protrude farther from the skull which means their jaw muscles probably do too, "The mechanical result of moving these masticatory muscles forward is to produce greater bite force," Beard says.

The adaptation to northern latitudes didn't stop at the jaw. The animals are also much larger than their southern relatives.

 "Five pounds doesn't sound very big, but compared to their ancestors, these are giants. The closest relative of this animal we found in Wyoming is about the size of a squirrel," he explains.

Overall, there is a general trend in ecology called Bergmann's rule which states that the further away animals live from the equator, the larger they become.

Size is a general adaptation to colder temperatures, and for animal species typically found in the tropics, the coastal climate of modern Georgia would be quite cool, requiring a large size to minimize heat loss. As the planet warms, more species will likely colonize the Arctic. But as in the case of Ignacius, many won’t simply colonize but may diversify into new species once there.