A polar bear with hair loss (alopecia) along its neck. The bear was captured by USGS scientists using the immobilizing drug Telazol
Polar Bear Research Active
Polar bears (Ursus maritimus) are one of 4 marine mammal species managed by the U.S. Department of Interior. The USGS Alaska Science Center leads long–term research on polar bears to inform local, state, national and international policy makers regarding conservation of the species and its habitat. Our studies, ongoing since 1985, are focused on population dynamics, health and energetics, distribution and movements, maternal denning, and methods development. The majority of our research focuses on the two polar bear subpopulation’s whose range includes Alaska: the Southern Beaufort Sea subpopulation that ranges between the North Slope of Alaska and western Canada and the Chukchi Sea or Alaska-Chukotka subpopulation that ranges between the northwest coast of Alaska and eastern Russia. The overarching goal of our research is to assess current and projected future responses of polar bears to a rapidly changing Arctic environment.
Return to Ecosystems >> Marine Ecosystems
Video: Polar Bear Collar Cam
Video: About the Polar Bear Research Program
Video: Melting Arctic Sea Ice Threatens Polar Bears
Population Dynamics
Information on the status and trends of polar bear populations are needed to inform management of polar bears under US laws and international agreements. The USGS maintains a long-term research program focused on the population dynamics of the southern Beaufort Sea polar bear population. In addition, the USGS collaborates with the US Fish and Wildlife Service in population studies in the Chukchi Sea. To estimate both the population size and vital rates, we have used mark-recapture studies relying on physical capture of bears, primarily during the spring. We are currently developing an analytical approach that will allow us to integrate additional types of data (e.g., spatial data, non-invasively collected genetic data) into the modeling process to provide improved assessments of population status. Results of past studies have allowed us to assess the relationships between population vital rates and environmental change, which provides our partners with information needed to inform management decisions.
Health and Energetics
The warming climate has the potential to drive significant changes in the health and energetics of Arctic fauna, particularly those dependent on sea ice habitats like polar bears. An animal’s health and energetic state reflects the interaction between its behavioral choices and the environment. Because of this, measuring changes in health and energetics has potential for revealing important associations between environmental stressors and population dynamics. Research in this focal area is centered on (i) collecting data on a variety of systems that help determine and mediate polar bear health and energetics, and (ii) developing monitoring and surveillance programs for detecting changes in population health over time. Additionally, this work will allow us to develop an understanding of how polar bear populations will respond to a variety of stressors modulated by climate change, including contaminant and pathogen exposures, changes in food web structure and prey accessibility, and changes in spatial distribution.
Distribution and Movements
Polar bears are tied to the sea ice for nearly all of their life cycle functions. Most important of these is foraging, or access to food. Polar bears almost exclusively eat seals, and they are equally as dependent upon the sea for their nutrition as are seals, whales, and other aquatic mammals. Polar bears are not aquatic, however, and their only access to the seals is from the surface of the sea ice. Over the past 25 years, the summer sea ice melt period has lengthened, and summer sea ice cover has declined by over half a million square miles. In winter, there have been dramatic reductions in the amount of old ice, predominantly in the western Arctic. This loss of stable old ice has catalyzed additional losses of sea ice cover each summer because the thinner younger ice is more easily melted during the recent warmer summers. Research in this focal area seeks to develop a better understanding of how changes in the distribution and characteristics of sea ice habitat are likely to affect polar bear fitness, distribution, and interactions with people. If we know how polar bears respond to changes in ice quantity and quality, we will be able to predict how forecasted changes in the ice may affect future polar bear populations. This will give managers the best chance of adapting strategies to assure the long-term persistence of polar bears in a changing ice environment.
Maternal Denning
Pregnant polar bears enter maternity dens in October or early November, give birth to cubs in December or early January, and exit dens in March or early April. Historically, most polar bears from the Southern Beaufort Sea population constructed maternity dens on the sea ice. However, over the last three decades, as sea ice has become thinner and more prone to fragmentation, there has been a landward shift in the distribution of dens. Based on data collected from radio-tagged adult female bears, maternal denning now occurs at relatively high densities along the central and eastern Arctic coastal plain of Alaska. The availability of denning habitat― mediated by landscape features that facilitate the formation of snow drifts― appears to increase in the eastern portion of the Alaska coastal plain. In the Chukchi Sea, polar bears historically denned primarily on land in both Russia and the Alaska. In recent years as sea ice extent has retreated further north in the fall, Chukchi Sea polar bears have shifted land-based denning northward primarily on Wrangel and Herald Islands in Russia and rarely on the Alaskan coast. Identifying factors influencing the distribution of dens and denning duration will allow us to better monitor reproductive success and mitigate the potential for disturbance of denned bears from anthropogenic activities.
Below are other science projects associated with this project.
Below are data or web applications associated with this project.
Satellite Location and Tri-axial Accelerometer Data from Adult Female Polar Bears (Ursus maritimus) in the Southern Beaufort Sea, April-October 2014
Measurement Data of Polar Bears Captured in the Chukchi and Southern Beaufort Sea, 1981-2017
Locations Collected 1985-2015 from Female Polar Bears (Ursus maritimus) with Dependent Young Instrumented in the Southern Beaufort Sea with Satellite-linked Transmitters by the USGS
Bioelectrical Impedance, Deuterium Dilution, Body Mass, and Morphological Measures of Southern Beaufort Sea Female Polar Bears, Spring 2014-2016
Metabolic Rate, Body Composition, Foraging Success, Behavior, and GPS Locations of Female Polar Bears (Ursus maritimus), Beaufort Sea, Spring, 2014-2016 and Resting Energetics of an Adult Female Polar Bear
Measures of oxygen consumption and stroke frequency of a captive subadult polar bear (Ursus maritimus) while resting in water and swimming and diving in a metabolic water flume, Oregon Zoo, 2017
Accelerometer Data from Collared Female Polar Bears in the Beaufort Sea, 2009-2016
Polar Bear Distribution and Habitat Resource Selection Data, Beaufort and Chukchi Seas, 1985-2016
Data from a Circumpolar Survey on Recreational Activities in Polar Bear Habitat, 2017-2018
Denning Behavior Classifications Using Temperature Sensor Data on Collars Deployed on Polar Bears in the Southern Beaufort Sea, 1986-2013
Sensor and Location data from Ear Tag PTTs Deployed on Polar Bears in the Southern Beaufort Sea 2009 to 2011
Fatty Acid Signature Data of Chukchi Sea Polar Bears, 2008-2015
Below are multimedia associated with this project.
A polar bear with hair loss (alopecia) along its neck. The bear was captured by USGS scientists using the immobilizing drug Telazol
A polar bear stands on a low-lying barrier shoal near the Huluhula River on the Beaufort Sea coast of Alaska. Coastal erosion along the Arctic coast is chronic, widespread and potentially accelerating, posing threats to infrastructure important for defense and energy purposes, natural shoreline habitats and nearby Native communities.
A polar bear stands on a low-lying barrier shoal near the Huluhula River on the Beaufort Sea coast of Alaska. Coastal erosion along the Arctic coast is chronic, widespread and potentially accelerating, posing threats to infrastructure important for defense and energy purposes, natural shoreline habitats and nearby Native communities.
Eric Reghr and Kristin Simac working on an anesthetized polar bear
Eric Reghr and Kristin Simac working on an anesthetized polar bear
George Durner collecting data on an anesthetized polar bear
George Durner collecting data on an anesthetized polar bear
Polar bear mother and two cubs on the Beaufort Sea ice.
Polar bear mother and two cubs on the Beaufort Sea ice.
Below are publications associated with this project.
Diet-driven mercury contamination is associated with polar bear gut microbiota
New insights into dietary management of polar bears (Ursus maritimus) and brown bears (U. arctos)
Effects of sea ice decline and summer land use on polar bear home range size in the Beaufort Sea
Iñupiaq knowledge of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska
Survival and abundance of polar bears in Alaska’s Beaufort Sea, 2001–2016
Energetic and health effects of protein overconsumption constrain dietary adaptation in an apex predator
Human-polar bear interactions
Diet composition and body condition of polar bears (Ursus maritimus) in relation to sea ice habitat in the Canadian High Arctic
Measuring adrenal and reproductive hormones in hair from southern Beaufort Sea polar bears (Ursus maritimus)
Polar bear foraging behavior
Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea
Polar Bear (Ursus maritimus)
Below are news stories associated with this project.
Below are partners associated with this project.
Polar bears (Ursus maritimus) are one of 4 marine mammal species managed by the U.S. Department of Interior. The USGS Alaska Science Center leads long–term research on polar bears to inform local, state, national and international policy makers regarding conservation of the species and its habitat. Our studies, ongoing since 1985, are focused on population dynamics, health and energetics, distribution and movements, maternal denning, and methods development. The majority of our research focuses on the two polar bear subpopulation’s whose range includes Alaska: the Southern Beaufort Sea subpopulation that ranges between the North Slope of Alaska and western Canada and the Chukchi Sea or Alaska-Chukotka subpopulation that ranges between the northwest coast of Alaska and eastern Russia. The overarching goal of our research is to assess current and projected future responses of polar bears to a rapidly changing Arctic environment.
Return to Ecosystems >> Marine Ecosystems
Video: Polar Bear Collar Cam
Video: About the Polar Bear Research Program
Video: Melting Arctic Sea Ice Threatens Polar Bears
Population Dynamics
Information on the status and trends of polar bear populations are needed to inform management of polar bears under US laws and international agreements. The USGS maintains a long-term research program focused on the population dynamics of the southern Beaufort Sea polar bear population. In addition, the USGS collaborates with the US Fish and Wildlife Service in population studies in the Chukchi Sea. To estimate both the population size and vital rates, we have used mark-recapture studies relying on physical capture of bears, primarily during the spring. We are currently developing an analytical approach that will allow us to integrate additional types of data (e.g., spatial data, non-invasively collected genetic data) into the modeling process to provide improved assessments of population status. Results of past studies have allowed us to assess the relationships between population vital rates and environmental change, which provides our partners with information needed to inform management decisions.
Health and Energetics
The warming climate has the potential to drive significant changes in the health and energetics of Arctic fauna, particularly those dependent on sea ice habitats like polar bears. An animal’s health and energetic state reflects the interaction between its behavioral choices and the environment. Because of this, measuring changes in health and energetics has potential for revealing important associations between environmental stressors and population dynamics. Research in this focal area is centered on (i) collecting data on a variety of systems that help determine and mediate polar bear health and energetics, and (ii) developing monitoring and surveillance programs for detecting changes in population health over time. Additionally, this work will allow us to develop an understanding of how polar bear populations will respond to a variety of stressors modulated by climate change, including contaminant and pathogen exposures, changes in food web structure and prey accessibility, and changes in spatial distribution.
Distribution and Movements
Polar bears are tied to the sea ice for nearly all of their life cycle functions. Most important of these is foraging, or access to food. Polar bears almost exclusively eat seals, and they are equally as dependent upon the sea for their nutrition as are seals, whales, and other aquatic mammals. Polar bears are not aquatic, however, and their only access to the seals is from the surface of the sea ice. Over the past 25 years, the summer sea ice melt period has lengthened, and summer sea ice cover has declined by over half a million square miles. In winter, there have been dramatic reductions in the amount of old ice, predominantly in the western Arctic. This loss of stable old ice has catalyzed additional losses of sea ice cover each summer because the thinner younger ice is more easily melted during the recent warmer summers. Research in this focal area seeks to develop a better understanding of how changes in the distribution and characteristics of sea ice habitat are likely to affect polar bear fitness, distribution, and interactions with people. If we know how polar bears respond to changes in ice quantity and quality, we will be able to predict how forecasted changes in the ice may affect future polar bear populations. This will give managers the best chance of adapting strategies to assure the long-term persistence of polar bears in a changing ice environment.
Maternal Denning
Pregnant polar bears enter maternity dens in October or early November, give birth to cubs in December or early January, and exit dens in March or early April. Historically, most polar bears from the Southern Beaufort Sea population constructed maternity dens on the sea ice. However, over the last three decades, as sea ice has become thinner and more prone to fragmentation, there has been a landward shift in the distribution of dens. Based on data collected from radio-tagged adult female bears, maternal denning now occurs at relatively high densities along the central and eastern Arctic coastal plain of Alaska. The availability of denning habitat― mediated by landscape features that facilitate the formation of snow drifts― appears to increase in the eastern portion of the Alaska coastal plain. In the Chukchi Sea, polar bears historically denned primarily on land in both Russia and the Alaska. In recent years as sea ice extent has retreated further north in the fall, Chukchi Sea polar bears have shifted land-based denning northward primarily on Wrangel and Herald Islands in Russia and rarely on the Alaskan coast. Identifying factors influencing the distribution of dens and denning duration will allow us to better monitor reproductive success and mitigate the potential for disturbance of denned bears from anthropogenic activities.
Below are other science projects associated with this project.
Below are data or web applications associated with this project.
Satellite Location and Tri-axial Accelerometer Data from Adult Female Polar Bears (Ursus maritimus) in the Southern Beaufort Sea, April-October 2014
Measurement Data of Polar Bears Captured in the Chukchi and Southern Beaufort Sea, 1981-2017
Locations Collected 1985-2015 from Female Polar Bears (Ursus maritimus) with Dependent Young Instrumented in the Southern Beaufort Sea with Satellite-linked Transmitters by the USGS
Bioelectrical Impedance, Deuterium Dilution, Body Mass, and Morphological Measures of Southern Beaufort Sea Female Polar Bears, Spring 2014-2016
Metabolic Rate, Body Composition, Foraging Success, Behavior, and GPS Locations of Female Polar Bears (Ursus maritimus), Beaufort Sea, Spring, 2014-2016 and Resting Energetics of an Adult Female Polar Bear
Measures of oxygen consumption and stroke frequency of a captive subadult polar bear (Ursus maritimus) while resting in water and swimming and diving in a metabolic water flume, Oregon Zoo, 2017
Accelerometer Data from Collared Female Polar Bears in the Beaufort Sea, 2009-2016
Polar Bear Distribution and Habitat Resource Selection Data, Beaufort and Chukchi Seas, 1985-2016
Data from a Circumpolar Survey on Recreational Activities in Polar Bear Habitat, 2017-2018
Denning Behavior Classifications Using Temperature Sensor Data on Collars Deployed on Polar Bears in the Southern Beaufort Sea, 1986-2013
Sensor and Location data from Ear Tag PTTs Deployed on Polar Bears in the Southern Beaufort Sea 2009 to 2011
Fatty Acid Signature Data of Chukchi Sea Polar Bears, 2008-2015
Below are multimedia associated with this project.
A polar bear with hair loss (alopecia) along its neck. The bear was captured by USGS scientists using the immobilizing drug Telazol
A polar bear with hair loss (alopecia) along its neck. The bear was captured by USGS scientists using the immobilizing drug Telazol
A polar bear stands on a low-lying barrier shoal near the Huluhula River on the Beaufort Sea coast of Alaska. Coastal erosion along the Arctic coast is chronic, widespread and potentially accelerating, posing threats to infrastructure important for defense and energy purposes, natural shoreline habitats and nearby Native communities.
A polar bear stands on a low-lying barrier shoal near the Huluhula River on the Beaufort Sea coast of Alaska. Coastal erosion along the Arctic coast is chronic, widespread and potentially accelerating, posing threats to infrastructure important for defense and energy purposes, natural shoreline habitats and nearby Native communities.
Eric Reghr and Kristin Simac working on an anesthetized polar bear
Eric Reghr and Kristin Simac working on an anesthetized polar bear
George Durner collecting data on an anesthetized polar bear
George Durner collecting data on an anesthetized polar bear
Polar bear mother and two cubs on the Beaufort Sea ice.
Polar bear mother and two cubs on the Beaufort Sea ice.
Below are publications associated with this project.
Diet-driven mercury contamination is associated with polar bear gut microbiota
New insights into dietary management of polar bears (Ursus maritimus) and brown bears (U. arctos)
Effects of sea ice decline and summer land use on polar bear home range size in the Beaufort Sea
Iñupiaq knowledge of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska
Survival and abundance of polar bears in Alaska’s Beaufort Sea, 2001–2016
Energetic and health effects of protein overconsumption constrain dietary adaptation in an apex predator
Human-polar bear interactions
Diet composition and body condition of polar bears (Ursus maritimus) in relation to sea ice habitat in the Canadian High Arctic
Measuring adrenal and reproductive hormones in hair from southern Beaufort Sea polar bears (Ursus maritimus)
Polar bear foraging behavior
Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea
Polar Bear (Ursus maritimus)
Below are news stories associated with this project.
Below are partners associated with this project.