A new study suggests that dramatic temperature shifts linked to climate change led to the extinction of several large mammals during the last ice age. Researchers found that woolly mammoth, cave lion and short-faced bear populations dwindled because of raising temperatures and abrupt climate shifts.
Researchers believe that in Late Pleistocene sharp temperature spikes, dubbed interstadials, boosted global temperatures by up to 29 degrees F, or 16 degrees C, in a few decades. As a result, large mammals soon went extinct because increased temperatures had a devastating effect on both their bodies and food stock.
Alan Cooper, lead author of the study and researcher at the University of Adelaide’s Australian Center for Ancient DNA in Australia, explained that interstadials negatively affected “global rainfall and vegetation patterns.”
Scientists used a computer model to see whether colder periods recorded in the Late Pleistocene also influenced large animals of that period. The model showed that only interstadials were linked with large die-offs at a local level and extinction of several species at a planetary level.
The research team also estimates that humans pushed some species toward extinction. For instance, as temperatures got hotter, large animals were unable to migrate to cooler locations, because human settlements disrupted their environments, while hunters kept reducing their numbers.
This latest study planned to examine the causes that led to the extinction of the animals weighing more than 99 pounds, also known as megafauna, in the latest ice age. Other studies had tried to do so, as well. Some researchers put the blame on large floods for the extinction of mammoths and giant ground sloths, while others pointed the finger at ice age hunters or temperature shifts.
Darwin was also puzzled by the die-offs when he came across fossils of megafauna in Latin America.
But Cooper and his team used DNA analysis of dozens of fossils and sifted through the DNA data on countless extinction events in the Late Pleistocene to get to the bottom of the issue. The DNA traces revealed that some species went extinct both globally and locally. Researchers also found major population turnovers at a local level, which means that one population went extinct and another one tried to take its place.
The researchers then introduced the DNA data into a computer model and looked for a link between dramatic temperature shifts and the die-offs. The data on extreme climate events were gathered from Greenland ice cores and ancient layers of sediments in Venezuela.
“The high-resolution view we gained through this approach clearly showed a strong relationship between warming events and megafaunal extinctions,”
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