Arctic Ground Squirrel Studies

What Are They Doing?

Arctic Ground SquirrelArctic Ground Squirrel In the Arctic, bright summers and dark winters are a fact of life and can lead humans to rely on clocks and routines to tell them when to eat or sleep, but how do animals function under these conditions? Circadian rhythms refer to the "internal body clock" that regulates the approximately 24-hour cycle of biological processes in animals and plants. Rhythms in body temperature, brain wave activity, hormone production, and other biological activities are linked to this 24-hour cycle. The Earth's light-dark cycle provides the strongest influence on circadian rhythms and is thought to be the primary driver for the emergence and evolution of internal clocks. In the Polar Regions, however, photoperiod exhibits extreme annual variation because of near 24 hour sunlight in the summer and 24 hour darkness in the winter. In the absence of a well-defined light-dark cycle, some arctic residents lose their daily organization of behavior and physiology, and it is thought that the molecular clockwork that drives circadian rhythms may be weak or absent in arctic vertebrates.

The research team has recently found that the arctic ground squirrel displays daily rhythms of body temperature throughout the arctic summer, in the absence of a light-dark cycle. The current study continues investigate the circadian rhythms in arctic ground squirrels during the continuous daylight present during the active summer season and continuous dark of the 6-8 months of hibernation spent sequestered in a burrow. The team wants to understand why arctic ground squirrels, unlike other arctic vertebrates, appear to maintain 24-hour rhythms during the active season. They hypothesize that the persistence of circadian rhythmicity allows ground squirrels to reduce energy expenditure by anticipating predictable changes in its immediate surroundings. They continue to test their hypothesis by experimentally phase-shifting free-living ground squirrels to be active at 'night' and estimating their subsequent rates of energy expenditure.

Where Are They?

Toolik Field Station, AlaskaToolik Field Station, Alaska From Fairbanks, Alaska the team embarked on a ten hour drive to Toolik Field Station, located in the northern foothills of the Brooks Range in northern Alaska. Toolik Field Station is operated by the Institute of Arctic Biology at the University of Alaska Fairbanks and has hosted hundreds of researchers and students every year since 1975. The team's research sites around the Toolik Lake area is accessed by pick-up truck, on foot, and occasionally by bicycle.


Baby sik sik
Mosquitoes, Baby Squirrels, and Final Trapping Days I have been back in Oklahoma for just over a week now, cooking in 90-104 degree temperatures. I miss the 40-50 degree days back in the Arctic, but I sure don’t miss the mosquitoes. From what I see on fellow PolarTREC teacher Nell Kemp’s blog, I left just before the mosquitoes got really intense! Unfortunately, I also left a couple of days before the first baby squirrels emerged from their burrows. Kate was kind enough to send me a couple of pictures though! Aren't they adorable? Baby Arctic Ground Squirrels (Photo by Kate Wilsterman...
Tundra transformation
Did I mention that things change quickly in the Arctic? During my month at Toolik Field Station, Toolik Lake transitioned from almost completely frozen (with researchers walking on the ice) to almost completely thawed (with researchers boating on the water and people doing polar plunges). From June 1 through June 28, I took a photo of the lake from the same spot each day to track the progress of the melting ice and I put them together into a quick video to show the thawing of Toolik Lake. In another example of how quickly...
Team Squirrel
Dealing with Goodbye Today was it. My last day working on the tundra. My last full day in the Arctic. My last day with Team Squirrel. Team Squirrel: Kate Wilsterman, Jeanette Moore, Cory Williams, Alicia Gillean On one hand, I am ready to head home: I am ready to be back with David, excited about planning how to best share my adventures in the Arctic with my students and colleagues, looking forward to flush toilets and long showers, and craving Mexican food. On the other hand, I hate leaving before Team Squirrel’s work is done (the rest of the team is staying about 5 days after I...
Team Squirrel's truck
Before the school year ended, some of my students asked great questions about my summer work in the Arctic. I think I have touched on most of them during the course of the past month, but I’ll do a quick run-down of some of the kids’ FAQs, just to be sure! Feel free to ask your own questions in the “Ask the Team” section! Before we get started, I wanted to share a fun picture of the Team Squirrel truck. Alicia and Jeanette next to Team Squirrel’s truck. It gets a little bit dirty at Toolik! Squirrel Diet What does the Arctic ground squirrel eat? Where do they go to eat? Can they eat...
Photo board
The photo board in the Dining Hall at Toolik is a great place to check to remind yourself of the names of other people in camp. People are sorted by the name of the lab space they work in, but not Team Squirrel, as you can see! I can’t believe that I only have a few days left in the Arctic. I am so grateful for the experiences I have had and the people I have met on this adventure. I want to introduce you to some of the passionate and brilliant scientists that I have had the pleasure to work with this summer. It is inspiring to hear why they chose careers in science, what they most...

Expedition Resources

Project Information

29 May 2013 to 4 July 2013
Location: Toolik Field Station, Alaska
Project Funded Title: Collaborative Research: Persistence, entrainment, and function of circadian rhythms in arctic ground squirrels

Meet the Team

Alicia Gillean's picture
Jenks West Intermediate School
Jenks, OK
United States

Alicia Gillean is a library media specialist at Jenks West Intermediate School, part of the Jenks Public Schools District, near Tulsa, Oklahoma. She is passionate about guiding her 5th and 6th grade students to develop as thinkers, inquirers, and citizens who have the ability to answer their own questions and the power to impact the world. Mrs. Gillean taught 6th grade at Jenks West Intermediate for four years before accepting her current position in 2010.

Prior to her work in traditional education, she was an Education Specialist at the Oklahoma Aquarium where she created and facilitated educational programs for aquarium guests. Mrs. Gillean has a bachelor of science degree in elementary education and a master of science degree in library media and information technology. In 2012, Mrs. Gillean was selected as a NOAA Teacher at Sea and spent eleven days living and working aboard the R/V Hugh R. Sharp as part of a science team conducting a survey of Atlantic sea scallops, providing her with tremendous examples of real-world science to share with her students. Mrs. Gillean is an adventurer and an outdoor enthusiast who spends her free time camping, hiking, running, reading, and traveling.

Cory Williams's picture
Northern Arizona University
Flagstaff, AZ
United States

Cory Williams is currently a research assistant professor at Northern Arizona University. His research examines the physiological and behavioral mechanisms that allow animals to cope with environmental change. Specifically, he is interested in the functional and ecological significance of circadian rhythms in arctic vertebrates and the factors underlying plasticity in the timing of annually recurring life-cycle events. Ultimately, the capacity of polar animals to adjust their timing in response to changing environmental conditions, either through phenotypic plasticity or microevolution, will be an important determinant of their resilience to climate change.

Brian Barnes's picture
University of Alaska Fairbanks
Fairbanks, AK
United States

Brian McRae Barnes is a biologist at the University of Alaska Fairbanks with research interests in the behavioral and physiological strategies for overwintering in northern animals, including those of the hibernating arctic ground squirrel and black bear and freeze tolerant or supercooling insects and wood frogs. He is also interested in biological timing, at scales of minute-to-minute decision making, rhythms of daily activity and seasonal reproduction and fattening, and annual timing of hibernation. Dr. Barnes has 27 years of research experience in the Alaskan Arctic and is Science Director of the Toolik Field Station and Director of the Institute of Arctic Biology.

Loren Buck's picture
University of Alaska Anchorage
Anchorage, AK
United States

Loren Buck, Professor of Biological Sciences at the University of Alaska Anchorage, is a physiological ecologist interested in adaptations of animals to extreme and variable environments. The Arctic is an extreme environment, characterized by radical seasonal changes in temperature, day length and food availability, all of which have served to shape, through evolutionary change, the extreme physiology of its resident animals such that they not only survive but thrive.

The Arctic is also a changing environment. Over the past 50 years, the Arctic has warmed more rapidly than any other place on the planet and climate models predict further and accelerated warming over the decades to come. Using a combination of laboratory and field approaches, Loren's laboratory is currently investigating mechanisms, function and plasticity of biological rhythms in the arctic ground squirrel.

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