Arctic birds weaken their own immune systems to save energy for hunting and to keep warm during the coldest months, research shows
- Research authors examined the immune system of the Svalbard rock ptarmigan
- They discovered that it can intentionally weaken its immune system to save energy
- It does this during the five coldest months of the year, from October to March
Birds living in the frozen polar region can take extreme measures to save energy – they can weaken their immune systems during the coldest months to keep warm.
Doing this exposes them to health risks, but makes them more energy efficient, which also helps with hunting, according to the Lund University team.
The Swedish researchers investigated the strength of the immune system of the Svalbard rock ptarmigan furthest in the Arctic from a land bird for the study.
This possibility proves particularly important during the five coldest months of the year, when there is no daylight – from October to March.
The Swedish researchers examined the immune system strength of the Svalbard rock ptarmigan furthest in the Arctic from a land bird for the study.
Researchers from Lund University, led by Dr. Andreas Nord, discovered that although the birds are used to the extremely cold, harsh conditions, this was a coping mechanism.
“We have found that the birds reduce how much they spend on maintaining their own immune systems during the five months of the year when it is dark around the clock, probably to save energy,” said Nord.
Instead, they use those resources to keep warm and look for food. When daylight returns, their immune response is boosted again. ‘
These birds are used to extremely cold, harsh environments, but researchers were fascinated to discover that their immune response varies between winter and late spring.
They found that when the birds get sick in the middle of winter, their energy consumption drops compared to when they are healthy – but when the birds got sick in late spring, their energy consumption increased.
Dr. Nord said, “A weaker immune system is likely to be part of all the adaptations polar animals use to conserve energy in winter.
“The risk of becoming infected in the north by various diseases is less in winter than when it gets warmer in summer.”
To save energy, the Svalbard rock ptarmigan weakens an already weak immune system.
They found that when the birds get sick in the middle of winter, their energy consumption drops compared to when they are healthy – but when the birds got sick in late spring, their energy consumption increased
The ability is probably due to the fact that the species evolved in the Arctic, where there was less of a need for a very strong immune system.
“This could have negative consequences if climate change and migratory birds arrive earlier in the Arctic and leave later,” said Nord.
He added that “more and more tourists are also landing in places where people have not yet set foot”, that the birds with a lower immune system could be more exposed.
“Such a scenario paves the way for increased disease risk and could threaten animals that have evolved in the Arctic, where a strong immune system may not have been needed.”
The findings are published in the Journal of Experimental Biology.