The woolly mammoth, a relative of the elephant, is one of the most famous extinct creatures in Earth’s history.
How exactly the species became extinct 4,000 years ago is a mystery, but a study presents an interesting new theory.
Researchers in Europe point to plant pollen, which they say caused allergies in mammoths that damaged their sense of smell.
This made it harder to smell a mate from a distance, which affected reproduction rates, eventually leading to population decline and collapse.
Scientists have debated the woolly mammoth’s extinction for decades, but the new study adds to prevailing theories, including hunting by humans.
Woolly mammoths descend from African ancestors and were widespread in northern Europe, Asia and North America during the last Ice Age (file photo)
Researchers analyzed tissue samples from mammoth carcasses recovered from the permafrost in northeastern Siberia. Pictured here, protein sample from the mammoth trunk
The new study was conducted by scientists from Israeli company SpringStyle, the Russian Academy of Sciences, the University of Catania and the Polytechnic University of Milan in Italy.
The team notes that modern elephants, which share a common ancestor with mammoths, have “a more sensitive sense of smell.”
“During the breeding season, susceptibility to odors is very important for animals,” they say in their article, published in Earth History and Biodiversity.
‘The development of allergies to plant pollen… could lead to a decrease in sensitivity to odours in animals during the breeding season.
‘This could explain the extinction of animals due to the decline in sexual relations.’
The woolly mammoth (Mammuthus primigenius) was one of the last of a line of mammoth species that existed before their extinction about 4,000 years ago.
At around 13 feet (four metres) tall and weighing around six tonnes, this huge mammal was widespread across northern Europe, Asia and North America during the last Ice Age.
Woolly mammoths coexisted with early humans, who hunted them for food and used their bones and tusks to make weapons and art.
However, the cause of their extinction is uncertain and there is intense debate about the role of human hunting and severe climate change.
Woolly mammoths were covered in thick brown fur to keep warm in the freezing conditions, which often dropped to -50°C.
Modern elephants share a common ancestor with mammoths (Primeelaphas, which lived 7-2 million years ago)
For the new study, researchers analyzed tissue samples from mammoth carcasses recovered from the permafrost in northeastern Siberia.
They found traces of immunoglobulins, also known as antibodies: Y-shaped proteins that the immune system uses to fight infections.
They also detected allergens such as plant metabolites, volatile organic compounds and pollen that the mammoths would have ingested from the air.
Taken together, these results suggest indicate the presence of allergic diseases and associated symptoms, including loss of the sense of smell.
Pollen-rich plants that flourished as the climate steadily warmed may have added to the woolly mammoths’ plight.
“It is likely that these changes in the allergic responses of mammoths during the period of climate change led to a decline in the mammoth population and, as a result, to their disappearance,” the authors say.
Woolly mammoths were elephant-like animals that evolved on the Arctic peninsula of Eurasia about 600,000 years ago. The last mammoths became extinct about 4,000 years ago, more recently than the construction of the pyramids at Giza in Egypt.
Pictured is a frozen woolly mammoth calf ‘Dima’, as displayed at the Museum of Zoology in St Petersburg, Russia; note the fur on the legs
A 39,000-year-old female woolly mammoth calf named Yuka, from the Siberian permafrost, is presented to the media at an exhibition in Yokohama, outside Tokyo, July 9, 2013.
The study’s authors say that no one else had published this theory of allergy or detected immunoglobulin fragments in mammoths before.
They do, however, acknowledge prevailing theories about why the species became extinct, including “mammoth hunting by primitive people.”
However, the debate is likely to continue and the physical evidence provides a variety of compelling arguments.
In 2015, British researchers claimed to have put “the nail in the coffin” of the debate after comparing extinction events in different areas with the expansion of humans.
They put the blame squarely on humans after discovering that as prehistoric humans expanded across continents and islands, the creatures quickly became extinct.
Another genetic study in 2008 concluded that climate change and disease were the most likely causes of the extinction.
More recently, a 2021 study concluded that melting icebergs as the climate warmed rapidly wiped out the vegetation on which mammoths depended.