As a Research Wildlife Biologist, I conduct studies focused on the ecology, physiology, and behavior of large mammals to understand their response to environmental change, identify what environmental or ecological factors (e.g., prey availability, winter temperature, ice availability, etc.) most influence whether a population increases, decreases, or is stable, and to maintain positive wildlife-human interactions.
I work with international and bilateral groups, such as the Polar Bear Range States and US-Russia Polar Bear Commission, DOI partners, including U.S. Fish and Wildlife Service, the Bureau of Land Management, and the U.S. National Park Service, Alaska Native co-management groups, and local and state governments to identify and address research needs for polar bears and walruses. My research focuses primarily on identifying biological and ecological indicators for monitoring large mammal populations and ecosystem change and determining mechanisms of population regulation in response to environmental change. I also study wildlife interactions with humans in areas of industry, via tourism and recreation, and in local communities to help minimize or avoid negative effects on wildlife and ensure human safety. Much of my work is centered on nutritional and physiological ecology and its effects on wildlife body condition, reproduction, and survival. Often, I work to develop new methods needed to address information needs. Although all research questions pertain to wild populations, I also regularly conduct studies with animals in zoos and other captive settings where more detailed study of animal physiology and development of new research techniques are possible.
Mar 2012 - Present Research Wildlife Biologist, USGS Alaska Science Center
Oct 2006 - Feb 2012 Wildlife Biologist, US Fish and Wildlife Service Polar Bear Program, Anchorage, Alaska
Jan 2006 - Oct 2006 Research Associate, Cornell University, Forest Elephant program
June 2002 - Dec 2005 Contract wildlife biologist - Alaska Department of Fish and Game/PhD candidate - Washington State University
Education and Certifications
Ph.D. Washington State University Zoology
M.S. Washington State University Zoology
B.S. Colorado State University Wildlife Biology
Affiliations and Memberships*
2020 - present Vice President- Americas, International Association of Bear Research and Management
2017 - present International Association of Bear Research and Management Grants Review Committee
2017 - present Member of the American Zoological Association’s Polar Bear Research Council
2015 - present Member of Science/TEK working group of the US Fish and Wildlife Service Polar Bear Recovery Team
2009 - 2010 Secretary/Treasurer of the Alaska chapter of the Wildlife Society
2008 - present Member of the International Union for the Conservation of Nature's (IUCN) Polar bear specialist group
2007 - present Member of the Scientific/TEK working group under the US-Russia polar bear commission
Science and Products
Observed and forecasted changes in land use by polar bears in the Beaufort and Chukchi Seas, 1985–2040
Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics
Intrapopulation differences in polar bear movement and step selection patterns
The role of satellite telemetry data in 21st century conservation of polar bears (Ursus maritimus)
Summer/fall diet and macronutrient assimilation in an Arctic predator
Subsurface swimming and stationary diving are metabolically cheap in adult Pacific walruses (Odobenus rosmarus divergens)
New insights into dietary management of polar bears (Ursus maritimus) and brown bears (U. arctos)
Long-term variation in polar bear body condition and maternal investment relative to a changing environment
Fatty acid profiles of feeding and fasting bears: Estimating calibration coefficients, the timeframe of diet estimates, and selective mobilization during hibernation
Iñupiaq knowledge of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska
Energetic and health effects of protein overconsumption constrain dietary adaptation in an apex predator
Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Q&A: Polar Bears and Zoos
Distribution and Movements of Polar Bears
Health and Energetics of Polar Bears
Polar Bear Research
Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017
Metabolic Rates Measured in Three Captive Adult Female Walruses (Odobenus rosmarus divergens) While Resting and Diving
Protein and Fat Consumption of Zoo Polar Bears in 14-day Ad Libitum Trials, 2019-2020
Denning Phenology, Den Substrate, and Reproductive Success of Female Polar Bears (Ursus maritimus) in the southern Beaufort Sea 1986-2013 and the Chukchi Sea 1987-1994
Carbon and Nitrogen Isotope Concentrations in Polar Bear Hair and Prey from the Alaska Beaufort and Chukchi Seas, 1978-2019
Fatty Acid Composition of Polar Bear Adipose Tissue and Ringed and Bearded Seal Blubber Collected in the Chukchi Sea, 2008-2017
Serum Urea and Creatinine Levels of Spring-Caught Polar Bears (Ursus maritimus) in the Southern Beaufort and Chukchi Seas
Measurement Data of Polar Bears Captured in the Chukchi and Southern Beaufort Sea, 1981-2017
Accelerometer Data from Collared Female Polar Bears in the Beaufort Sea, 2009-2016
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
Fatty Acid Signature Data of Chukchi Sea Polar Bears, 2008-2015
Science and Products
Filter Total Items: 52
Observed and forecasted changes in land use by polar bears in the Beaufort and Chukchi Seas, 1985–2040Monitoring changes in the distribution of large carnivores is important for managing human safety and supporting conservation. Throughout much of their range, polar bears (Ursus maritimus) are increasingly using terrestrial habitats in response to Arctic sea ice decline. Their increased presence in coastal areas has implications for bear-human conflict, inter-species interactions, and polar bear h
Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamicsSea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator-prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under-ice food web to meet their energy needs. Here, we assessed whe
Intrapopulation differences in polar bear movement and step selection patternsBackgroundThe spatial ecology of individuals often varies within a population or species. Identifying how individuals in different classes interact with their environment can lead to a better understanding of population responses to human activities and environmental change and improve population estimates. Most inferences about polar bear (Ursus maritimus) spatial ecology are based on data from a
The role of satellite telemetry data in 21st century conservation of polar bears (Ursus maritimus)Satellite telemetry (ST) has played a critical role in the management and conservation of polar bears (Ursus maritimus) over the last 50 years. ST data provide biological information relevant to subpopulation delineation, movements, habitat use, maternal denning, health, human-bear interactions, and accurate estimates of vital rates and abundance. Given that polar bears are distributed at low dens
Summer/fall diet and macronutrient assimilation in an Arctic predatorFree-ranging predator diet estimation is commonly achieved by applying molecular-based tracers because direct observation is not logistically feasible or robust. However, tracers typically do not represent all dietary macronutrients, which likely obscures resource use as prey proximate composition varies and tissue consumption can be specific. For example, polar bears (Ursus maritimus) preferentia
Subsurface swimming and stationary diving are metabolically cheap in adult Pacific walruses (Odobenus rosmarus divergens)Walruses rely on sea-ice to efficiently forage and rest between diving bouts while maintaining proximity to prime foraging habitat. Recent declines in summer sea ice have resulted in walruses hauling out on land where they have to travel farther to access productive benthic habitat while potentially increasing energetic costs. Despite the need to better understand the impact of sea ice loss on ene
New insights into dietary management of polar bears (Ursus maritimus) and brown bears (U. arctos)Although polar bears (Ursus maritimus) and brown bears (U. arctos) have been exhibited in zoological gardens for centuries, little is known about their nutritional needs. Multiple recent studies on both wild and captive polar bears and brown bears have found that they voluntarily select dietary macronutrient proportions resulting in much lower dietary protein and higher fat or digestible carbohydr
Long-term variation in polar bear body condition and maternal investment relative to a changing environmentIn the Arctic, warming air and ocean temperatures have resulted in substantial changes to sea ice, which is primary habitat for polar bears (Ursus maritimus). Reductions in extent, duration, and thickness have altered sea ice dynamics, which influences the ability of polar bears to reliably access marine mammal prey. Because nutritional condition is closely linked to population vital rates, a prog
Fatty acid profiles of feeding and fasting bears: Estimating calibration coefficients, the timeframe of diet estimates, and selective mobilization during hibernationAccurate information on diet composition is central to understanding and conserving carnivore populations. Quantitative fatty acid signature analysis (QFASA) has emerged as a powerful tool for estimating the diets of predators, but ambiguities remain about the timeframe of QFASA estimates and the need to account for species-specific patterns of metabolism. We conducted a series of feeding experime
Iñupiaq knowledge of polar bears (Ursus maritimus) in the southern Beaufort Sea, AlaskaSuccessful wildlife management depends upon coordination and consultation with local communities. However, much of the research used to inform management is often derived solely from data collected directly from wildlife. Indigenous people living in the Arctic have a close connection to their environment, which provides unique opportunities to observe their environment and the ecology of Arctic sp
Energetic and health effects of protein overconsumption constrain dietary adaptation in an apex predatorStudies of predator feeding ecology commonly focus on energy intake. However, captive predators have been documented to selectively feed to optimize macronutrient intake. As many apex predators experience environmental changes that affect prey availability, limitations on selective feeding can affect energetics and health. We estimated the protein:fat ratio of diets consumed by wild polar bears us
Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi SeaPolar bears (Ursus maritimus) are experiencing loss of sea ice habitats used to access their marine mammal prey. Simultaneously, ocean warming is changing ecosystems that support marine mammal populations. The interactive effects of sea ice and prey are not well understood yet may explain spatial‐temporal variation in the response of polar bears to sea ice loss. Here, we examined the potential com
Non-USGS Publications**Voorhees, H., R. Sparks, H. P. Huntington, and K. D. Rode. 2014. Traditional knowledge of polar bears (Ursus maritimus) in Northwestern Alaska. Arctic 67(4):523-436. doi:10.14430/arctic4425.Erlenbach, J. A., K. D. Rode, D. Raubenheimer, and C. M. Robbins. 2014. Macronutrient optimization and energy maximization determine diets of brown bears. Journal of Mammalogy 95(1):160-168. doi:10.1644/13-MAMM-A-161.Robbins, C. T., C. Lopez-Alfaro, K. D. Rode, Ø. Tøien, and O. L. Nelson. 2012. Hibernation and seasonal fasting in bears: the energetic costs and consequences for polar bears. Journal of Mammalogy 93(6):1493-1503. doi:10.1644/11-MAMM-A-406.1.Whiteman, J. P., K. A. Greller, H. J. Harlow, L. A. Felicetti, K. D. Rode, and M. Ben-David. 2012. Carbon isotopes in exhaled breath track metabolic substrates in brown bears (Ursus arctos). Journal of Mammalogy 93:413-421. doi:10.1644/11-MAMM-S-178.1.Gleason, J. S. and K. D. Rode. 2009. Polar bear distribution and habitat association reflect long-term changes in fall sea ice conditions in the Alaskan Beaufort Sea. Arctic 62(4):405-417.Schliebe, S. L., K. D. Rode, J. S. Gleason, J. Wilder, K. M. Proffitt, T. J. Evans, and S. Miller. 2008. Effects of sea ice extent and food availability on spatial and temporal distribution of polar bears during the fall open-water period in the Southern Beaufort Sea. Polar Biology 31(8):999-1010. doi:10.1007/s00300-008-0439-7.Stirling, I., A. E. Derocher, W. Gough, and K. D. Rode. 2008. Response to Dyck et al. (2007) on polar bears and climate change in western Hudson Bay. Ecological Complexity 5(3):193-201. doi:10.1016/j.ecocom.2008.01.004.Rode, K. D., S. C. Amstrup, and E. V. Regehr. 2007. Polar bears in the southern Beaufort Sea III: Stature, mass, and cub recruitment in relationship to time and sea ice extent between 1982 and 2006. USGS Administrative Report, 31 p.Robbins, C. T., J. K. Fortin, K. D. Rode, S. D. Farley, L. A. Shipley, and L. A. Felicetti. 2007. Optimizing protein intake as a foraging strategy to maximize mass gain in an omnivore. Oikos 116(10):1675-1682. doi:10.1111/j.0030-1299.2007.16140.x.Fortin, J. K., S. D. Farley, C. T. Robbins, and K. D. Rode. 2007. The role of salmon and berries in determining fall weight gains in brown bears. Ursus 18(1):19-29. doi:10.2192/1537-6176(2007)18[19:DASOBS]2.0.CO;2.Rode, K. D., S. D. Farley, and C. T. Robbins. 2006. Behavioral responses of brown bears mediate nutritional impacts of experimentally introduced tourism. Biological Conservation 133(1):70-80. doi:10.1016/j.biocon.2006.05.021.Rode, K. D., C. A. Chapman, L. D. McDowell, and C. A. Stricker. 2006. Nutritional mechanisms of population regulation across habitats and logging intensities in redtail monkeys (Cercopithecus ascanius). Biotropica 38:625-634. doi:10.1111/j.1744-7429.2006.00183.x.Rode, K. D., P. I. Chiyo, C. A. Chapman, and L. D. McDowell. 2006. Nutritional ecology of elephants in Kibale National Park, Uganda, and its relationship with crop raiding behaviour. Journal of Tropical Ecology 22(4):441-449. doi:10.1017/S0266467406003233. https://doi.org/10.1017/S0266467406003233
Rode, K. D., S. D. Farley, and C. T. Robbins. 2006. Sexual dimorphism, reproductive strategy, and human activities determine resource use by brown bears. Ecology 87(10):2636-2646. doi:10.1890/0012-9658(2006)87[2636:SDRSAH]2.0.CO;2.Danish, L., C. A. Chapman, C. O'Driscoll Worman, K. D. Rode, and M. B. Hall. 2006. The role of sugar content in diet selection in redtail and red colobus monkeys. In Feeding Ecology in apes and other primates. Cambridge University Press, UK.Chapman, C. A., L. J. Chapman, K. D. Rode, and L. D. McDowell. 2003. Variation in the nutritional value of primate foods: Among trees, time periods, and areas. International Journal of Primatology 24(2):317-337. doi:10.1023/A:1023049200150.Rode, K. D., C. A. Chapman, L. J. Chapman, and L. D. McDowell. 2003. Mineral resource availability and consumption by colobus monkeys in Kibale National Park, Uganda. International Journal of Primatology 24(3):541-573. doi:10.1023/A:1023788330155.Chapman, C. A., L. J. Chapman, M. Cords, M. Gauthua, A. Gautier-Hion, J. E. Lambert, K. D. Rode, C. E. G. Tutin, and L. J. T. White. 2002. Variation in the Diets of Cercopithecus Species: Differences Within Forests, Among Forests, and Across Species. In The Guenons: Diversity and Adaptation in African Monkeys. M. Glenn and M. Cords (eds.). Plenum Press New York City, NY, USA.Rode, K. D., C. T. Robbins, and L. A. Shipley. 2001. The constraints on herbivory by bears. Oecologia 128(1):62-71. doi:10.1007/s004420100637.Rode, K. D. and C. T. Robbins. 2000. Why bears consume mixed diets during fruit abundance. Canadian Journal of Zoology 78(9):1-6. doi:10.1139/z00-082.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Q&A: Polar Bears and ZoosPolar bears are found throughout the circumpolar Arctic and roam across miles of sea ice and land. They prefer to eat blubber, especially from seals that are also found on the sea ice. However, the sea ice habitat of polar bears is changing rapidly with substantial recent declines in the extent of sea ice in the Arctic. These changes are leading polar bears to spend more time on land in some areas...
Distribution and Movements of Polar BearsPolar 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...
Health and Energetics of Polar BearsResearch 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...
Polar Bear ResearchPolar 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...
Walrus ResearchThe USGS Alaska Science Center conducts long-term research on the Pacific walrus to provide scientific information to Department of Interior management agencies and Alaska Native co-management partners. In addition, the USGS Pacific walrus research program collaborates with the U.S. Fish and Wildlife Service (USFWS) and the State of Alaska’s Department of Fish and Game and Alaska Native co...
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Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017his dataset consists of one table with estimated locations of adult female polar bears during July-November 1985-2017, used for quantifying changes in summer land use over time. Locations were estimated with a Continuous Time-Correlated Random Walk (CTCRW) model fit to satellite tracking from radio-collared adult female polar bears. All bears included in this data set were captured and instrumente
Metabolic Rates Measured in Three Captive Adult Female Walruses (Odobenus rosmarus divergens) While Resting and DivingThis dataset contains measurements of oxygen consumption and carbon dioxide production of 3 adult female walruses (Odobenus rosmarus divergens) while resting and diving at the Oceanografic Aquarium in Valencia, Spain. Oxygen consumption and carbon dioxide production was measured for walruses via a respiratory dome while resting at the water surface and after swimming and diving.
Protein and Fat Consumption of Zoo Polar Bears in 14-day Ad Libitum Trials, 2019-2020This is a single table containing measures of the amount of fat and meat consumed by 4 adult female and 5 adult male polar bears in U.S. zoos when provided both food sources ad libitum for 12-14 days. Trial length was intended to be 14 days, but trial dietary items ran out for two bears prior to the end of the trial (i.e., at 12 and 13 days instead of 14 days). The data set includes the weight of
Denning Phenology, Den Substrate, and Reproductive Success of Female Polar Bears (Ursus maritimus) in the southern Beaufort Sea 1986-2013 and the Chukchi Sea 1987-1994These data represent estimates of den entrance and exit dates for female polar bears in the southern Beaufort and Chukchi Seas based on temperature sensor data obtained from satellite collars. An algorithm described in Olson et al. (2017) was used to determine whether the female entered a den and further analyses using temperature data as described in Olson et al. (2017) were used to assess den en
Carbon and Nitrogen Isotope Concentrations in Polar Bear Hair and Prey from the Alaska Beaufort and Chukchi Seas, 1978-2019This dataset includes carbon and nitrogen isotope concentrations measured in polar bear hair and marine mammal prey samples collected 1978-2017 in the Beaufort and Chukchi Seas. Marine mammal prey samples were collected opportunistically either from polar bear seal kill sites or from marine mammals harvested by Native hunters. Hair was collected from polar bears captured on the sea ice or land in
Fatty Acid Composition of Polar Bear Adipose Tissue and Ringed and Bearded Seal Blubber Collected in the Chukchi Sea, 2008-2017These data are the fatty acid compositions (in %) of adipose tissue samples collected from polar bears and of blubber samples collected from ringed and bearded seal killed by polar bears in the Chukchi Sea, 2008-2017. The dataset includes sex, age, and age class of the bears that were sampled. The data are provided as % of each fatty acid identified via nomenclature that describes the structure of
Serum Urea and Creatinine Levels of Spring-Caught Polar Bears (Ursus maritimus) in the Southern Beaufort and Chukchi SeasThese data are serum urea nitrogen and creatinine levels for polar bears captured in the southern Beaufort Sea 1983-2016 and the Chukchi Sea 1987-1993 and 2008-2017. The dataset includes relevant information about the bears that were captured including the latitude and longitude of their capture location, capture date, age class and sex, the age and number of cubs accompanying an adult female, and
Measurement Data of Polar Bears Captured in the Chukchi and Southern Beaufort Sea, 1981-2017This dataset includes measures collected on polar bears captured in the Chukchi and Beaufort Seas, 1981-2017 by the U.S. Geological Survey and U.S. Fish and Wildlife Service. Data collected include body length, body mass, axillary girth, skull width and tail lengths. Bears were also aged as described in the methods. For some bears, an adipose tissue sample was collected and percent lipid content w
Accelerometer Data from Collared Female Polar Bears in the Beaufort Sea, 2009-2016This dataset includes accelerometer data collected on collars deployed on female polar bears in the southern Beaufort Sea from 2009-2016. The accelerometer was built in to collars by Telonics, Inc. and provides a single activity value of the number of seconds active per time interval of data collection. Data were collected every 15-30 minutes. GPS and ARGOs locations collected via collars were use
Data from a Circumpolar Survey on Recreational Activities in Polar Bear Habitat, 2017-2018These data are the responses of researchers, managers, community members, and tour guides who live or work in polar bear habitats anywhere within their range to inquiries about the types, frequency, and potential impacts of recreational activities. Respondents answered a series of questions on their background and experience with polar bears and the geographic area in which they are familiar. Resp
Denning Behavior Classifications Using Temperature Sensor Data on Collars Deployed on Polar Bears in the Southern Beaufort Sea, 1986-2013These data include two spreadsheets. The first is average daily temperatures received via satellite transmitting collars deployed on polar bears in the southern Beaufort Sea 1986-2013. The second is denning classifications for adult female polar bears in the southern Beaufort Sea using the temperature data. Denning was classified using a control chart-based algorithm applied to the temperature d
Fatty Acid Signature Data of Chukchi Sea Polar Bears, 2008-2015These data were collected to gain insights into the diet composition of Chukchi Sea polar bears. These data were collected to gain insights into the diet composition of Chukchi Sea polar bears.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government