By feeding Arctic ground squirrels special diets, researchers have found that omega-3 fatty acids, which are common in flaxseed and fish oil, help keep the animals warmer in deep hibernation.
A study conducted by the University of Alaska Fairbanks fed ground squirrels either an omega-3-rich diet or a normal laboratory diet and measured how the animals hibernated afterwards. The researchers found that the omega-3 diet helped the animals hibernate slightly warmer than normal without negatively affecting hibernation. The omega-3 diets also increased the amount of a heat-producing fat called brown adipose tissue that the animals wrap up.
The discovery could lead to a better understanding of how hibernation works and why animals eat certain types of foods. The study was published in Scientific Reports on January 14th.
“Arctic ground squirrels have an innate ability to withstand incredibly long sub-zero temperatures,” says Monica Mikes, who was a bachelor’s researcher at the UAF and a researcher in the university’s biomedical learning and student training program at the time of the study.
Mikes, who also co-designed the study, found that the animals can bring their body temperature below freezing point. How hibernation regulates body temperature has fascinated researchers for over a century. The type of fat they eat could have something to do with it.
Recent studies have shown that omega-3 fatty acids can affect metabolism in animals that do not hibernate. Because wild hibernators are known to consume diets rich in omega-3 foods, the researchers wanted to know if these animals benefit from these diets.
“Fat is incredibly important during hibernation,” said lead author Sarah Rice, who holds a PhD. Student at the UAF Institute of Arctic Biology at the time of the study. “These animals not only live on their fat stores, but the more people study certain types of fat, the more they realize that certain types of fat can help regulate the body and signal it to do certain things.”
Scientists know that hibernation specifically searches for and stores polyunsaturated fatty acids, so-called PUFAs, before hibernation. While omega-6 PUFAs have been well studied during hibernation and are known to lower temperature, omega-3 fatty acids have received less research.
Because Arctic ground squirrels are exposed to extreme cold in their natural burrows, consuming more omega-3s to increase brown adipose tissue can help ward off extreme cold in the wild. The researchers in this study did not investigate which foods ground squirrels in the wild could provide with such omega-3 fatty acids.
People know that eating omega-3 fatty acids like fish oil is good for them. Apparently, squirrels can detect this too, and it can have specific effects on hibernation. “
Sarah Rice, lead author
University of Alaska Fairbanks
Rice, SA et al. (2021) Omega-3 fatty acids stimulate thermogenesis during solidification in the arctic ground squirrel. Scientific reports. doi.org/10.1038/s41598-020-78763-8.