A vegetation explosion at the end of the last ice age may have produced so much pollen that it blocked mammoths’ sense of smell. A new study suggests that this may have driven the animals to extinction, but not everyone agrees. Pollen clouds floating across the mammoth steppe at the end of the last ice age may have led to the extinction of woolly mammoths, a new study suggests.

The researchers say the vegetation explosion caused by global warming may have released so much pollen that it could have caused allergic reactions in the animals, blocked their sense of smell and prevented them from communicating normally with each other. The team say the mammoths’ inability to smell each other during breeding season would have prevented them from finding mates, leading to a rapid population decline and eventual extinction.

“One possible mechanism for animal extinction during climate change could be the deterioration of smell due to the development of allergies when the flora changes,” the researchers wrote in a study published Aug. 27 in the journal “Earth History and Biodiversity.” “The aim of this study is to propose a new evolutionary mechanism for the extinction of mammoths and other animals based on the disruption of communication.”

Woolly mammoths (Mammuthus primigenius) lived during the Pleistocene epoch (2.6 million to 11,700 years ago). They disappeared from most of their range by about 10,000 years ago, although a small population survived until 4,000 years ago on Wrangel Island, a remote island off the coast of northeastern Russia. Researchers believe that inbreeding, human hunting, and major changes in vegetation led to the mammoth’s extinction, although there is ongoing debate about how much each of these factors contributed to the mammoth’s demise.

Allergies can disrupt many vital functions in a mammoth’s life, the researchers say. The animals used their sense of smell to find food and mates, navigate during migration and avoid predators, so stuffed mammoths may have doomed them, the researchers wrote in the paper.

The authors of the new study suggest that one way to test whether mammoths suffered from allergies would be to test the contents of their stomachs for allergenic plants and pollen. Some bodies also have pollen embedded in mummified tissue or in preserved plant material around them, which could help identify past irritants, according to the study.