Allergies May Have Contributed to Mammoth extinction, New Research Suggests
A novel hypothesis proposes that allergies, specifically reactions to pollen similar to hay fever, may have played a role in the extinction of mammoths and other large mammals at the end of the last Ice Age. While climate change and human hunting are well-established factors, this research suggests that a shift in vegetation and subsequent allergic responses could have weakened populations, making them more vulnerable.
For decades,scientists have puzzled over why so many large mammals,including the woolly mammoth,woolly rhinoceros,and mastodon,disappeared around 11,700 years ago. The prevailing theories center on climate change – the warming temperatures after the last glacial period dramatically altered habitats – and overhunting by early humans. Though, these explanations don’t fully account for the timing and widespread nature of the extinctions.
To explore a new avenue,researchers investigated tissue samples from frozen remains of several Ice Age animals,including the woolly mammoth and woolly rhinoceros. They discovered evidence of proteins associated with the immune system that are similar to those involved in allergic reactions in modern mammals. This suggests that these ancient creatures possessed the biological machinery to experience allergies.
Crucially, the team also identified traces of pollen from plants known to cause allergic reactions in contemporary mammals. One such plant is Oxytropis sordida, a legume that produces allergenic pollen.The researchers theorize that as the climate warmed, forests and grasslands expanded, increasing the abundance of these allergenic plants. This surge in pollen could have triggered widespread allergic reactions, impacting the animals’ health and reproductive success.
“The idea is that as the environment changed, new plants moved in, and these plants produced pollen that the mammoths hadn’t encountered before,” explains dr. Charlotte Oskam, a paleobiologist at the University of Copenhagen and lead author of the study published in Earth History and Biodiversity. “Their immune systems would have reacted to these novel pollens, causing inflammation and possibly weakening them.”
[Image of protein sampling from a mammoth trunk – credit: Gleb Zilberstein]
Though, researchers emphasize that the “hay fever” hypothesis doesn’t negate existing theories. The extinction of the mammoths was likely a complex event driven by multiple, interacting factors.climate change, human hunting, habitat loss, and potentially inbreeding due to declining populations all likely contributed to their demise. Allergies, according to this new research, may have been an additional stressor that tipped the balance.
Looking ahead,the research team hopes to find direct evidence of immunoglobulin E (IgE),an antibody produced during allergic reactions,in fossilized tissues. While IgE is notoriously difficult to detect after thousands of years, its presence would provide stronger confirmation of allergic responses in mammoths.
Current research is also investigating the animals’ ability to cope with plant toxins. Beyond pollen, other compounds in the changing vegetation could have weakened the animals, making them more susceptible to disease and less able to survive in a rapidly changing environment.
Sources:
* Oskam, C.L., et al. (2024).Allergenicity of postglacial vegetation and its potential role in the extinction of megafauna. Earth History and Biodiversity. https://www.sciencedirect.com/science/article/pii/S295047592400008X
* University of Copenhagen. (2024, May 16).hay fever may have contributed to the extinction of mammoths. https://sciencenews.universityofcopenhagen.dk/english/hay-fever-may-have-contributed-to-the-extinction-of-mammoths/
* Smithsonian Magazine. (