Could the decline of a certain type of flower have caused the downfall of woolly mammoths (and the woolly rhinoceros) rather than more exotic explanations like climate change, over-hunting by our prehistoric ancestors, and a comet explosion?
After examining Arctic vegetation from the last 50,000 years, Eske Willerslev of the University of Copenhagen and his research team believe a regional extinction of plants known as forbs (such as sagebrush, yarrow, mums, and tansies) may have led to the giant beasts' extinction approximately 4,000 years ago, National Geographic reported. Their study was recently published in the journal "Nature."
Previous research determined grass as the main food source of food for woolly mammoths (they did not eat meat) based on pollen counts. According to Willerslev, however, grass has significantly higher pollen counts than other types of vegetation, meaning it may be misleading to assume it had been mammoths' primary dietary option based on that factor.
Analysis of 50,000 year old permafrost core samples supported Willerslev's point. They showed forbs -- and not grass - -as the dominant vegetation atop arctic steppes where mammoths grazed. Further support was found after researchers examined the stomach contents of woolly mammoth specimens, and determined that forbs occupied a significant portion of their diets.
Willersleve is convinced the change from forbs to grass was "a likely key reason for the decline and extinction of many megafuana species," as he told Nat Geo by email, while other scientists are more cautious.
"I think this is preliminary conclusion," Sergey Zimov (who did not participate in the study), director of Russia's Northeast Science Station, told Nat Geo.
Zimov was concerned about the limited number of specimens analyzed and the fact that forb populations existed beyond mammoths' reign. He does, however, think it unlikely that climate change entirely explains the extinction of the great beast, and believes there are remaining factors.
