Woolly Mammoths Went Extinct Because of Catastrophic Icing Events

The study, led by Laura Arppe from the Finnish Museum of Natural History, contradicts previous theories that attributed the mammoths' extinction to long-term climate change or genetic decline. Published in Quaternary Science Reviews, the research indicates that the Wrangel Island mammoths were not in decline before their sudden disappearance. Instead, it was the short-term, catastrophic icing events that led to their extinction.

“These types of events have been known to cause deaths of large numbers of herbivores in the Arctic,” explained Arppe. “20,000 musk oxen were starved to death in 2003 in the Canadian Arctic due to a rain-on-snow event.”

A Stable Environment Disrupted

After most of Earth's woolly mammoths died out, the last holdouts survived on Wrangel Island, outliving their mainland counterparts by 7,000 years. By analyzing the carbon and nitrogen isotopes in mammoth bones and teeth, Arppe's team gained insights into the nutrition and metabolic health of these mammoths in the years leading up to their extinction.

“No one had looked at what was going on with the dietary ecology of the Wrangelian mammoths, and with all these other observations related to diet, it was high time to do so,” said Arppe. The research found no alarming long-term changes in their diet or environment, indicating that the mammoths lived in relatively stable conditions until their abrupt extinction.

Comparing Past Theories

Previous studies suggested that a "genomic meltdown" due to inbreeding and a shrinking population size contributed to the mammoths' extinction. A 2017 study published in PLOS argued that genetic mutations impaired the mammoths' ability to socialize, procreate, and survive. However, Arppe's research found no evidence of such genetic decline before their extinction.

The Role of Fat Reserves and Freshwater Quality

The study also revealed that the Wrangel Island mammoths relied on their fat reserves during harsh winters, which likely contributed to their prolonged survival compared to other mammoth populations. However, the severe icing events overwhelmed this survival strategy, leading to their demise.

Additionally, the research suggested that the quality of available freshwater might have played a role in their extinction. While a 2017 study pointed to a lack of sufficient water, Arppe's research indicates that the poor quality of freshwater could have further stressed the mammoths, contributing to their decline.

The extinction of the last woolly mammoths on Wrangel Island around 4,000 years ago was not due to long-term climate change or genetic decline but rather to sudden and severe icing events. These findings provide a clearer understanding of the factors that led to the extinction of these iconic Ice Age creatures. As scientists continue to unravel the mysteries of the past, studies like this highlight the complex interplay between environment and survival in the natural world.

(Article image by Thomas Quine)