Birds turn off their immunity, otherwise they do not have enough energy to generate heat

Extremely cold, harsh environments and constant hunting for food mean that Arctic animals have become energy conservation experts. Now, researchers from Lund University in Sweden have discovered a previously unknown energy-saving method used by birds during the polar night. This was reported by the journal of experimental biology.

Researchers from the University of Lund and the University of Tromsø have studied the strength of the partridge’s immune system in Svalbard in the Arctic. This bird lives farthest in the Arctic from any other land-based bird, and the researchers watched how the immune response changes in winter and late spring.

“We found that birds reduce the performance of their own immune defense systems for five months a year when it is dark around the clock to save energy. Instead, they use these resources to keep warm and search for food. When daylight returns, their immune response is enhanced again”.

Andreas Nord, a researcher at Lund University.

Researchers have found that when birds fall ill in mid-winter, their energy consumption drops compared to when they are healthy. However, when birds fall ill in late spring, their energy consumption increases.

A weak immune system is probably part of all the adaptations that arctic animals use to save energy in winter. The risk of contracting various diseases in the north in winter is less than when it gets warmer by summer.

“This can have negative consequences when climate change occurs and migratory birds arrive earlier in the Arctic and fly off later. More and more tourists also go ashore in places where people have not set foot before. “This scenario opens the door to an increased risk of disease and may pose a threat to animals that have evolved in the Arctic, where a strong immune defense system may not have been required before.”

Andreas Nord, a researcher at Lund University.

When stone partridges on Svalbard save energy in this way, they weaken the already weak immune system. According to the researchers, this is probably due to the fact that this species evolved in the Arctic, where there was less need for a very strong immune defense system.

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