A new study has revealed the real reason woolly mammoths went extinct.
The now-extinct species of mammoth lived from the Middle Pleistocene until its extinction in the Holocene epoch, 4,000 years ago.
The woolly mammoth lived in Eurasia and North America. Its closest living relative is the Asian elephant. The last known group survived until 1650BC, over a thousand years after the Pyramids of Giza were built.
Around 13 feet (four metres) tall and weighing around six tons, the massive mammal was widespread during the last Ice Age.
Researchers now lay the blame for their extinction on plant pollen, which gave the mammoths allergies that damaged their sense of smell.
The claim this made it more difficult for them to smell potential mates which affected breeding rates, leading to population decline and collapse.
The new study adds to decades of debate on the extinction of the species, with prevailing theories including hunting by humans and climate change.
Woolly mammoths co-existed with early humans, who hunted them for food and used their bones and tusks for making weapons and art.
Researchers point out that the mammoth’s ancestors – elephants – have a “most sensitive sense of smell”.
“During the breeding season, susceptibility to odours is very important for animals,” they say in their paper, published in Earth History and Biodiversity.
“Development of allergies from plant pollen… could lead to decrements in sensitivity to odors in animals during the breeding season. This may explain the extinction of animals due to a decrease in sexual intercourse.”
The new study was conducted by scientists at Israeli firm SpringStyle, Russian Academy of Sciences, the University of Catania and Polytechnic University of Milan in Italy.