On our planet periodically there were periodsglobal warming and global cooling (ice ages). At the time of warming, the average temperature on the planet was much higher than now. For example, two million years ago, Greenland had a rich ecosystem, even mastodons, relatives of modern elephants, lived on the island. But one of the warmest periods on Earth was during the Eocene, which lasted from 56 to 33.9 million years ago. The Arctic was then also warm, mostly swampy with dense forests. During this period, two small primates lived on Ellesmere Island, which now belongs to Canada, which scientists have become aware of through a recent study of their fossils.
What was the climate in the Arctic during the Eocene era
The Eocene period was the most activeplanetary warming. At that time, the poles were not covered with ice. The Arctic island of Ellesmere, which lies north of Baffin Bay near Greenland, had a warm and humid climate similar to that of present-day Georgia in the United States. However, the ecosystem was unlike any existing on Earth at the present time.
The ecosystem of the Arctic was diverse, itincluded many unusual animals, such as early tapir-like ungulates, ancient crocodiles, snakes, salamanders, etc. However, despite the fact that these animals did not face extremely low temperatures, they still had to survive in quite harsh conditions.
Regardless of the temperature, the polar night inThe Arctic has always been, that is, for half a year the animals had to live in complete darkness. But the problem for them was not the long night itself, but the lack of food during this period. Vegetation in winter was very sparse, because plants need sunlight. In addition, although the Arctic was warm, its climate was still much colder than the equatorial zones. Therefore, animals had to adapt to survive in such an environment.
Ancient primates of the Eocene era
On the aforementioned Ellesmere Island, paleontologistsdiscovered fossils of unusual animals - these were jaws with teeth that belonged to mammals. The study showed that their age is about 52 million years. As it turned out, scientists were able to discover the remains of previously unknown species of small primates, which were given the name I. dawsonae and I. mckennai. Both of these species belonged to the same genus Ignacius, known to science for a long time.
I. dawsonae and I.mckennai are the oldest primates known to science to have lived in the Arctic. As the researchers report in the journal PLOS One, each animal weighed about two kilograms. In our time, it seems that these primates were very small, however, compared with their southern counterparts who lived in the same period, they were real giants.
But this is not their only feature.The study showed that the cheekbones of these animals protrude further from the skull than those of southern primates. This may indicate that their jaw muscles also bulged forward and were highly developed. Most likely, this allowed the animals to chew on the hard vegetation that was available to them during the Arctic winter.
How ancient animals adapted to northern conditions
According to researchers, fossil northernprimates of the genus Ignaceous ate hard-to-chew food such as tree bark, nuts, and seeds. Therefore, they needed powerful jaws for survival, at least. in winter time.
Relatively large body size compared tosouthern relatives, which were the size of a modern chipmunk, is also associated with the adaptation of animals to northern conditions. According to Bergen's rule, the farther from the equatoan animals live, the larger they are, as a rule. The large size is necessary to minimize heat loss.
According to scientists, during the Eocene warmingmany species began to shift their habitats to the north. The two primate species discovered are a prime example of how southern animals changed as they moved north, and formed new species. By the way, it was migration and the ability to adapt to environmental conditions that helped mammals survive after the catastrophe that destroyed the dinosaurs.
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Ecologists are now observing the same process inNowadays. Most likely, as the climate warms, many animals will also begin to populate the Arctic, and sooner or later they will turn into new species, as was the case with ancient animals. Earlier we said that, according to scientists, as a result of global warming, the Arctic may soon become a rainy region with a less severe climate.