The Ice Age giants’ mass extinction may be related to the disappearance of their main food source, the wildflowers that grew abundantly in their environment. In a study reported in the journal Nature, scientists believe the protein-rich wildflowers that once covered the Arctic permafrost, home to the Ice Age giants, dwindled and eventually disappeared due to ice age climate change. The change in vegetation may have happened 25,000 years ago and ended about 10,000 years ago. This time frame also coincides with the mass extinctions of the large animals of the period.
The so-called Ice Age giants include the mighty woolly mammoths and the woolly rhinoceros that once roamed the Arctic region teeming with small flowering plants and wildflowers known as forbs. According to Eske Willerslev, an expert in the study of ancient DNA from the University of Copenhagen who led an international team of scientists and researchers, the entire ice age Arctic environment has no shrubs and no trees but is dominated by small flowering plants. The scientists theorized that once the forbs disappeared, the Ice Age giants soon followed thereafter because the nutritional requirements of these large herbivores can no longer be sustained.
These findings contradicted the earlier idea that humans were to blame for the mass extinctions of these large animals. During the Ice Age, humans arrived in these regions and hunted these animals for food. There was overkill in the process prompting scientists to call the event the Blitzkrieg hypothesis.
The Arctic region was once also the home of other plant eaters like bison, horses, camels and reindeer, as well as meat-eaters like saber-toothed cats, huge short-faced bears, lions and hyenas. The Ice Age Arctic at the time was very cold, dry and probably dusty.
The scientists and researchers of this study analyzed the DNA of plants preserved in the permafrost with samples taken from 242 sites in Siberia and North America. Also included in the study were the feces and stomach contents taken from mummified remains of animals recovered in those places. According to the study co-author Grant Zazula, a paleontologist with the Yukon government, until this study, the diets of these animals and other herbivores that lived in the Ice Age Arctic region were a mystery. Previously, scientists thought the Ice Age arctic region did not contain much vegetation but just a small amount of grass.
To determine the age of the samples taken, radiocarbon dating was utilized. The DNA taken from the samples were then compared to the DNA of known plants. Zazula said that even if those plants are no longer in existence today, there are still some close relatives of those plants living today that can be compared with.
The DNA analysis also revealed the Ice Age Arctic region grew warmer and wetter which gave rise to the tundra people know of today dominated by woody plants and grasses. While the forbs-eating Ice Age giants slowly disappeared, a population explosion happened with the woody plant-eating animals like the moose, caribou and elk. These animals adapted to the new environment and out-competed the Ice Age giants and other herbivores over just a few hundred years.
The Ice Age giants’ mass extinction and the disappearance of their main food source, the wildflowers, is an indication of just how sensitive the environment is, this is a lesson everybody could stand to take note of.
By Roberto I. Belda