Winter is becoming shorter: "Animals don't fully understand what's happening"
When winter gets shorter, animals can become confused.
Due to global warming, winters are becoming shorter and more unpredictable.
Animals are noticing this too, and life can become more challenging.
Many animals depend on the weather to tell them when spring has arrived.
When these signals become unclear, not all animals understand them.
Why is winter getting shorter?
"In Norway, we know very well that winters are getting shorter. The Norwegian Meteorological Institute has been collecting measurements across the country for a long time. When we look at climate, we have to consider trends over time," says climate researcher Kari Alterskjær.
The Norwegian Meteorological Institute found that, on average, there were 118 winter days per year between 1961 and 1990. From 1991 to 2020, the average was 96 winter days.
“We know temperatures are rising due to human emissions, and we understand how greenhouse gases contribute to this increase. These are well-established facts,” says Alterskjær.
While winters are shortening, they are also becoming more unpredictable, with frequent fluctuations between below-freezing and above-freezing temperatures.
“This doesn’t mean winters will disappear entirely. For instance, last winter was unusually long and cold in Oslo and many other parts of Norway. So, even though we’re entering an era of shorter winters overall, we will still occasionally experience long, harsh winters,” the researcher explains.
Animals become confused
Temperature plays a role in determining when bears wake from hibernation and when birds return from warmer regions.
If temperatures change rapidly, it's no surprise that animals might become confused.
"The challenge is that many of these animals don't fully understand what's happening. Many rely on instincts to know when to perform certain actions, like hibernating or migrating south or north," explains biologist Irja Ida Ratikainen.
Animals are different
Not all animals are equally confused by the changes.
Some are able to adapt to the changing conditions.
Ratikainen explains that animals can adapt in two ways.
Some animals move to new areas that are more suitable for them after the climate changes.
"Generally, animals move higher in altitude or closer to the poles. In Norway, this means moving further north," she says.
Some animals can adapt by changing their appearance or behaviour.
"Some animals rely on day length to know when to start laying eggs or giving birth, but the day length that once signalled the right time for spring now arrives too late, as spring begins earlier in the year," says Ratikainen.
Day length refers to the amount of daylight. When days grow longer, some animals recognise that spring has arrived.
It’s somewhat easier for animals that monitor temperature changes instead.
Even though some animals are managing well, Ratikainen believes that most will face increasing challenges.
Some animals thrive
"In Norway, ticks are an example of a species that is thriving. Their numbers are increasing in areas where they've previously existed, and they're now surviving further north and at higher altitudes," says Ratikainen.
Other animals, like the red fox, are also doing well.
Unfortunately, this success comes at the expense of the Arctic fox.
When ung.forskning.no spoke with researcher Nina Elisabeth Eide about the Arctic fox last year, she said:
"There are many species under threat because other animals are more adaptable. The red fox are is one of the most successful species globally. In Norway, it also poses a threat to the Arctic fox."
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Translated by Alette Bjordal Gjellesvik
Read the Norwegian version of this article on ung.forskning.no
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