Arctic Squirrels Have a Climate Change Problem

Male arctic ground squirrels go through puberty every year. As if it wasn’t hard enough, women now have problems too.

According to a paper published Thursday in the journal Science, climate change appears to be bringing them out of their previous hibernation. This is important, because it can eliminate the timing of the animal’s mating cycle.

Usually, males come out of hibernation before females to prepare for the spring mating season. It takes time for them to reach sexual maturity again, every year, because testosterone levels drop significantly during winter.

Then, the woman woke up. But scientists have found that when temperatures rise, female ground squirrels emerge up to 10 days earlier than before. The researchers think that it is related to the previous thawing of the soil.

Male hibernation patterns, meanwhile, appear to be unchanged.

“This study shows that males and females of the same species may respond differently to climate change,” said Helen E. Chmura, a research ecologist with the United States Forest Service who is lead author of the paper. “This could have important implications for reproduction.”

The squirrel problem is part of a larger crisis. All over the world, wildlife is struggling. On land, the main cause is that humans have taken over too much of the planet, erasing the biodiversity that existed before. In the ocean, the main problem is overfishing. Climate change is making life more difficult.

Today, Arctic ground squirrels are still abundant in the wild. The International Union for Conservation of Nature classifies the species as a species of least concern, meaning it is not threatened or in need of conservation efforts. But the paper said the new hibernation mismatch “may affect the chances of survival.”

Any decline in squirrel populations could disrupt local food webs. Almost all arctic predators, from wolves to eagles, rely on them as a source of food.

Although the Arctic is warming faster than any other region on Earth, there is relatively little research on how this warming affects animals. This new paper, which covers more than 25 years in Northern Alaska, is one of the first long-term research projects to provide strong evidence that warming is directly changing the physiological processes of Arctic species.

“This study is relatively unusual because it shows that warming directly affects mammals,” said Cory T. Williams, assistant professor at Colorado State University and co-author of the study. “Some people might say, ‘Okay, a 10-day advance over 25 years doesn’t seem fast.’ But in terms of climate, it’s really fast.

Arctic ground squirrels may look cute, but males can be very territorial. They fight a lot during mating season, some of them get killed. They have a tail, but not long, bushy like the squirrels found in the south. And they make a distinctive whistling sound that can easily be mistaken for the chirping of a small bird. Some Alaska Natives call it a parka squirrel because its fur makes a nice, warm edge for the hood of a coat.

Scientists have long been interested in hibernation patterns.

During a long sleep, a squirrel’s core body temperature can drop to 27 degrees Fahrenheit, or about minus 3 Celsius, with its resting heart rate dropping to three beats per minute. More knowledge about these processes could lead to advances in therapeutic hypothermia, a medical treatment in which the body’s temperature is lowered to prevent injury. It is sometimes used after a heart attack.

But the most important challenge, scientists say, is to understand the changes taking place in the Far North.

“There’s a big gap in just knowing what’s going on in the Arctic in general,” said Dr. Williams. “This study shows why we need long-term projects to understand the changes that occur at different levels.”