Skip to main content
U.S. flag

An official website of the United States government

Todd Atwood, Ph.D.

Spatial ecology, population ecology, predator-prey dynamics, polar bear ecology

Professional Experience

  • 2012 - Present    Research Wildlife Biologist and Project Leader, USGS Alaska Science Center, Anchorage, AK

  • 2008 - 2012        Research Wildlife Biologist, USDA/APHIS/WS/National Wildlife Research Center, Fort Collins, CO

  • 2006 - 2008       Research Biologist, Research Branch, Arizona Game and Fish Department, Phoenix, AZ

  • 2006                    Biological Technician, USDA/National Wildlife Research Center, Fort Collins, CO

Education and Certifications

  • Ph.D.  2006   Utah State University   Wildlife Biology

  • M.S.    2002   Purdue University        Wildlife Ecology

  • B.S.     1999   Purdue University        Wildlife Ecology

Affiliations and Memberships*

  • The Wildlife Society

  • International Association for Bear Research and Management

  • American Society of Mammalogists

Science and Products

link
A polar bear walks across rubble ice in the Alaska portion of the southern Beaufort Sea

Q&A: Recent Research on Southern Beaufort Sea Polar Bears

Polar bears are found throughout the circumpolar Arctic and roam across miles of sea ice and land. There are 19 recognized subpopulations of polar bears across the Arctic with two in Alaska: the Chukchi Sea and the Southern Beaufort Sea. The sea ice habitat of these subpopulations is changing with substantial recent declines in the extent of sea ice off the coast of Alaska. These changes are...
By
Alaska Science Center
link

Q&A: Recent Research on Southern Beaufort Sea Polar Bears

Polar bears are found throughout the circumpolar Arctic and roam across miles of sea ice and land. There are 19 recognized subpopulations of polar bears across the Arctic with two in Alaska: the Chukchi Sea and the Southern Beaufort Sea. The sea ice habitat of these subpopulations is changing with substantial recent declines in the extent of sea ice off the coast of Alaska. These changes are...
Learn More
link
Female and two cubs polar bears on the sea ice

Polar Bear Maternal Denning

Pregnant polar bears enter maternity dens in October/November, give birth to cubs in December/January, and exit dens in March/April. Historically, most polar bears from the Southern Beaufort Sea (SBS) population constructed maternity dens on the sea ice. Over the last three decades, as sea ice has become thinner and prone to fragmentation, there has been a landward shift in the distribution of...
By
Species Management Research Program, Alaska Science Center
link

Polar Bear Maternal Denning

Pregnant polar bears enter maternity dens in October/November, give birth to cubs in December/January, and exit dens in March/April. Historically, most polar bears from the Southern Beaufort Sea (SBS) population constructed maternity dens on the sea ice. Over the last three decades, as sea ice has become thinner and prone to fragmentation, there has been a landward shift in the distribution of...
Learn More
link
Polar bear appears to walk on top of rippled gray water. Just behind it are very large breaking waves below a gray-blue sky.

Polar Bear 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...
By
Species Management Research Program, Alaska Science Center
link

Polar Bear 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...
Learn More
link
A polar bear walks across rubble ice in the Alaska portion of the southern Beaufort Sea

Distribution and Movements of Polar Bears

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...
By
Species Management Research Program, Alaska Science Center
link

Distribution and Movements of Polar Bears

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...
Learn More
link
Polar bear still hunting at a seal breathing hole

Health and Energetics of Polar Bears

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...
By
Species Management Research Program, Alaska Science Center
link

Health and Energetics of Polar Bears

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...
Learn More
link
Polar bear mother and two cubs on the Beaufort Sea ice.

Polar Bear Research

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...
By
Ecosystems, Land Management Research Program, Species Management Research Program, Alaska Science Center
link

Polar Bear Research

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...
Learn More
Filter Total Items: 14

Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017

his 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
By
Alaska Science Center

Genetic structure of American black bear populations in the American Southwest and northern Mexico, 1994-2014

Microsatellite genotypes for American black bears collected by Gould et al. 2002 and used to assess the genetic structure of American black bear populations in the American Southwest and northern Mexico. Genotypes are for Ursus americanus individuals.
By
Northern Rocky Mountain Science Center

Polar Bear Fall Coastal Survey Data from the Southern Beaufort Sea of Alaska, 2010-2013

This data set is one table with observations of polar bears located during aerial surveys along the coast and barrier islands of the southern Beaufort Seas during fall, 2010-2013. Survey flights were conducted using A-Star B2 and Bell 206 helicopters at an average altitude of 300 feet AGL and an average speed of 50 miles per hour. Survey crews searched for polar bears using coastal and inland tran
By
Alaska Science Center

Mapping data of Polar Bear (Ursus maritimus) maternal den habitat, Arctic Coastal Plain, Alaska

These are geospatial data that characterize the distribution of polar bear denning habitat on the National Petroleum Reserve-Alaska (NPR-A), the 1002 Area of the Arctic National Wildlife Refuge and the coastal plain of northern Alaska between the Colville River and the Alaska/Canada border.
By
Alaska Science Center

Pathogen and Contaminant Exposure Data from Southern Beaufort Sea Polar Bears, 2007-2014

These were data collected from polar bears from the Southern Beaufort Sea during the spring between 2007 and 2014. Data include individual ID, capture date, sex and age class, whether individuals visited bowhead whale carrion sites, exposure status relative to five pathogens, and concentrations of certain persistent organic pollutants.
By
Alaska Science Center

Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Southern Beaufort Sea, 1986-2016

This dataset consists of one table with predicted locations of adult female polar bears. Locations were derived by a Continuous Time-Correlated Random Walk (CTCRW) model using satellite tracking radio-collared adult female polar bears captured and instrumented in the southern Beaufort Sea, 1986–2016.
By
Alaska Science Center

Innate Immunity and Stress and Reproductive Hormone Metrics for Southern Beaufort Sea Polar Bears, 2013-2015

These were data collected from polar bears from the Southern Beaufort Sea during the spring between 2013 and 2015. Data include individual identification, demographic characteristics, year, status for the current and prior year regarding use of land, concentrations of stress response and reproductive hormones, blood-based biomarker measures indicative of fasting, body mass index, and body conditio
By
Alaska Science Center

Serum Urea and Creatinine Levels of Spring-Caught Polar Bears (Ursus maritimus) in the Southern Beaufort and Chukchi Seas

These 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
By
Alaska Science Center

Multistate capture and search data from the southern Beaufort Sea polar bear population in Alaska, 2001-2016

This data release contains two tables of information on polar bear distributions in the southern Beaufort Sea during spring, from 2001 to 2016. One table provides location (classified into 5 broad regions) of individual bears during the spring. The other table presents the aerial search effort by year and area.
By
Alaska Science Center

Polar Bear Microsatellite Data Southern Beaufort Sea 2010-2013

This data set provides Polar Bear microsatellite genotypes derived from twenty loci (G1A, G10B, G10C, CXX110, G1D, G10H, G10J, G10L, G10M, MSUT2, MU59, G10P, 145P07, CPH9, CXX20, MU50, MU51, G10X, CXX173, G10U). Samples for microsatellite genetic analysis were collected from polar bears from the southern Beaufort Sea during the spring and fall, 2010-2013. Tissue samples were collected from capture
By
Alaska Science Center

Satellite Location and Tri-axial Accelerometer Data from Adult Female Polar Bears (Ursus maritimus) in the Southern Beaufort Sea, April-October 2014

These data are from 5 adult female polar bears instrumented in the southern Beaufort Sea, April to October 2014. The dataset is comprised of two data packages: 1) contains GPS and Argos locations collected by satellite-linked GPS receivers mounted on external collars, and 2) contains archival logger data including measures of tri-axial acceleration and conductivity. These data were collected to ga
By
Alaska Science Center

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

This dataset contains a select subset of Argos and GPS locations collected by satellite data collection systems from collared adult female polar bears that were instrumented in the southern Beaufort Sea between 1985-2015. These data were collected to gain insights into movements of southern Beaufort Sea polar bears. These data were collected from adult female polar bears who had dependent young at
By
Alaska Science Center
Graphical abstract showing role of diet and food intake affecting polar bear population dynamics in southern Beaufort Sea.
link
Scientist talking with students participating in 2022 Brown University Environmental Leadership Lab.
link
Filter Total Items: 69

Efficacy of bear spray as a deterrent against polar bears

Although there have been few attempts to systematically analyze information on the use of deterrents on polar bears (Ursus maritimus), understanding their effectiveness in mitigating human-polar bear conflicts is critical to ensuring both human safety and polar bear conservation. To fill this knowledge gap, we analyzed 19 incidents involving the use of bear spray on free-ranging polar bears from 1
By
Ecosystems, Alaska Science Center

Observed and forecasted changes in land use by polar bears in the Beaufort and Chukchi Seas, 1985–2040

Monitoring 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
By
Ecosystems, Alaska Science Center

A serological survey of Francisella tularensis exposure in wildlife on the Arctic Coastal Plain of Alaska

Tularemia is an infectious zoonotic disease caused by one of several subspecies of Francisella tularensis bacteria. Infections by F. tularensis are common throughout the northern hemisphere and have been detected in more than 250 wildlife species. In Alaska, US, where the pathogen was first identified in 1938, studies have identified F. tularensis antibodies in a diverse suite of taxa, including i
By
Ecosystems, Alaska Science Center

Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics

Sea 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
By
Ecosystems, Alaska Science Center, Fort Collins Science Center

Modeling the spatial and temporal dynamics of land-based polar bear denning in Alaska

Although polar bears (Ursus maritimus) of the Southern Beaufort Sea (SBS) subpopulation have commonly created maternal dens on sea ice in the past, maternal dens on land have become increasingly prevalent as sea ice declines. This trend creates conditions for increased human–bear interactions associated with local communities and industrial activity. Maternal denning is a vulnerable period in the
By
Ecosystems, Alaska Science Center

Comparisons of Coupled Model Intercomparison Project Phase 5 (CMIP5) and Coupled Model Intercomparison Project Phase 6 (CMIP6) sea-ice projections in polar bear (Ursus maritimus) ecoregions during the 21st century

Climate model projections are commonly used to assess potential impacts of global warming on a breadth of social, economic, and environmental topics. Modeling centers throughout the world coordinate to apply a consistent suite of radiative forcing experiments so that all model outputs can be collectively analyzed and compared. Three generations of model outputs have been produced and made availabl
By
Ecosystems, Alaska Science Center

Using in situ/ex situ research collaborations to support polar bear conservation

A warming Arctic threatens the long-term persistence of polar bears (Ursus maritimus) in the wild. Historically, little collaboration existed between the in situ and ex situ polar bear scientific communities. However, for the past decade, zoo professionals, government agencies, and non-governmental organizations (NGO’s) have partnered to leverage resources and expertise with the goal of addressing
By
Ecosystems, Alaska Science Center

The ice don’t lie

No abstract available.
By
Ecosystems, Alaska Science Center

Evaluating the efficacy of aerial infrared surveys to detect artificial polar bear dens

The need to balance economic development with impacts to Arctic wildlife has been a prominent subject since petroleum exploration began on the North Slope of Alaska, USA, in the late 1950s. The North Slope region includes polar bears (Ursus maritimus) of the southern Beaufort Sea subpopulation, which has experienced a long-term decline in abundance. Pregnant polar bears dig dens in snow drifts dur
By
Ecosystems, Alaska Science Center

Marine mammal hotspots across the circumpolar Arctic

AimIdentify hotspots and areas of high species richness for Arctic marine mammals.LocationCircumpolar Arctic.MethodsA total of 2115 biologging devices were deployed on marine mammals from 13 species in the Arctic from 2005 to 2019. Getis-Ord Gi* hotspots were calculated based on the number of individuals in grid cells for each species and for phylogenetic groups (nine pinnipeds, three cetaceans, a
By
Ecosystems, Land Management Research Program, Alaska Science Center

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
By
Ecosystems, Alaska Science Center

Distinct gut microbiomes in two polar bear subpopulations inhabiting different sea ice ecoregions

Gut microbiomes were analyzed by 16S rRNA gene metabarcoding for polar bears (Ursus maritimus) from the southern Beaufort Sea (SB), where sea ice loss has led to increased use of land-based food resources by bears, and from East Greenland (EG), where persistent sea ice has allowed hunting of ice-associated prey nearly year-round. SB polar bears showed a higher number of total (940 vs. 742) and uni
By
Ecosystems, Alaska Science Center

Non-USGS Publications**

Algeo, T. P., D. Slate, R. M. Caron, T. C. Atwood, S. Recuenco, M. Ducey, R. B. Chipman, and M. Palace. 2017. Modeling raccoon (Procyon lotor) habitat connectivity to identify potential corridors for rabies spread. Tropical Medicine and Infectious Diseases 44. doi:10.3390/tropicalmed203044.
Atwood, T. C., E. Peacock, K. M. Lillie, R. R. Wilson, and S. Miller. 2015. Demographic composition and behavior of polar bears summering on shore in Alaska. USGS Administrative Report, 26 p.
Beasley, J. C., T. C. Atwood, M. E. Byrne, K. C. VerCauteren, S. R. Johnson, and O. E. Rhodes, Jr. 2015. A behaviorally-explicit approach for evaluating vaccine baits to mesopredators to control epizootics in fragmented landscapes. PLoS One 10:e0113206. doi:10.1371/journal.pone.0113206.
Anderson, A., S. A. Shwiff, R. B. Chipman, T. C. Atwood, T. Cozzens, F. Fillo, R. Hale, B. Hatch, J. Maki, O. E. Rhodes, Jr, E. E. Rees, C. E. Rupprecht, R. Tinline, K. C. VerCauteren, and D. Slate. 2014. Forecasting the spread of raccoon rabies using a purpose-specific group decision-making process. Human-Wildlife Interactions 8(1):130-138.
Slate, D., R. B. Chipman, T. P. Algeo, S. A. Mills, K. M. Nelson, C. K. Croson, E. J. Dubovi, R. W. Renshaw, K. C. VerCauteren, T. C. Atwood, S. Johnson, and C. E. Rupprecht. 2014. Safety and immunogenicity in the first field trial with ONRAB in raccoons in the United States. Journal of Wildlife Diseases 50(3):582-595. doi:10.7589/2013-08-207.
Kunkel, K. E., T. K. Ruth, T. C. Atwood, D. H. Pletscher, and M. G. Hornocker. 2013. Assessing the value of wolves and cougars as conservation surrogates by linking carnivore hunting success with landscape characteristics. Animal Conservation 16:32-40. doi:10.1111/j.1469-1795.2012.00568.x.
Beasley, J. D., W. S. Beatty, T. C. Atwood, S. Johnson, and O. E. Rhodes, Jr. 2012. A comparison of methods for estimating raccoon abundance: Implications for disease vaccination programs. Journal of Wildlife Management 76(6):1290-1297. doi:10.1002/jwmg.379.
Atwood, T. C. and S. W. Breck. 2012. Carnivores, Conflict, and Conservation: Defining the Landscape of Conflict. Pages 99-118 in F. I. Álvares and G. E. Mata, (eds.). Carnivores: Species, Conservation, and Management. Nova Publishers.
Atwood, T. C., T. L. Fry, and B. R. Leland. 2011. Partitioning of a limited resource by sympatric carnivores in the Chihuahuan Desert and the implications for disease transmission. Journal of Wildlife Management 75:1609-1615.
Atwood, T. C., J. K. Young, J. P. Beckmann, S. W. Breck, O. E. Rhodes, Jr, J. A. Fike, and K. D. Bristow. 2011. Modeling connectivity of black bears in a desert sky island archipelago. Biological Conservation 144(12):2851-2862. doi:10.1016/j.biocon.2011.08.002.
Fry, T. L., T. C. Atwood, and M. R. Dunbar. 2010. Utility of rhodamine B as a biomarker in raccoons. Human-Wildlife Interactions 4:275-282.
Atwood, T. C. and E. M. Gese. 2010. Importance of resource selection and social behaviour to partitioning of hostile space by sympatric canids. Journal of Mammalogy 91:490-499.
Atwood, T. C., T. J. DeLiberto, H. J. Smith, J. Stevenson, and K. C. VerCauteren. 2009. Raccoon spatial ecology related to cattle and bovine tuberculosis. Journal of Wildlife Management 73:647-654.
Atwood, T. C., E. M. Gese, and K. E. Kunkel. 2009. Spatial decomposition of predation risk in a multiple-predator multiple-prey system. Journal of Wildlife Management 73:876-884.
Atwood, T. C. and E. M. Gese. 2008. Coyotes (Canis latrans) and recolonizing wolves (Canis lupus): Social rank mediates risk-conditional behaviour at ungulate carcasses. Animal Behaviour 75:753-762.
VerCauteren, K. C., T. C. Atwood, T. J. DeLiberto, H. J. Smith, J. Stevenson, T. Gidlewski, and B. V. Thomsen. 2008. Sentinel-based surveillance of coyotes to detect bovine tuberculosis in Michigan. Emerging Infectious Diseases 14:1862-1869.
Atwood, T. C., K. C. VerCauteren, T. J. DeLiberto, H. J. Smith, and J. Stevenson. 2007. Coyotes as a potential sentinel species to detect bovine tuberculosis (Mycobacterium bovis) infection in white-tailed deer in Michigan. Journal of Wildlife Management 71:1545-1554.
Atwood, T. C., E. M. Gese, and K. E. Kunkel. 2007. Comparative patterns of predation by cougars and recolonizing wolves. Journal of Wildlife Management 71:1098-1106.
Atwood, T. C. 2006. The influence of habitat patch attributes on coyote group size and interaction in a fragmented landscape. Canadian Journal of Zoology 84:80-87.
Atwood, T. C. 2006. Behavioral interactions between wolves, Canis lupus, and coyotes, Canis latrans, at ungulate carcasses in southwest Montana. Western North American Naturalist 66:390-394.
Atwood, T. C., H. P. Weeks, Jr., and T. M. Gehring. 2004. Spatial ecology of coyotes along a suburban-to-rural gradient. Journal of Wildlife Management 85:1000-1009.
Swihart, R. K., T. C. Atwood, J. R. Goheen, D. A. Scheiman, K. E. Munroe, and T. M. Gehring. 2003. Patch occupancy in North American mammals: Is patchiness in the eye of the beholder? . Journal of Biogeography 30:1259-1279.
Atwood, T. C. and H. P. Weeks, Jr.. 2003. Sex-specific patterns of mineral lick preference in white-tailed deer. Northeastern Naturalist 10:409-414.
Atwood, T. C. and H. P. Weeks, Jr.. 2002. Sex- and age-specific patterns of mineral lick use by white-tailed deer. American Midland Naturalist 148:289-296.
Atwood, T. C. and H. P. Weeks, Jr.. 2002. Facultative dyad formation in adult male coyotes. Northeastern Naturalist 9:353-358.

**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.

link

Polar Bear Outlook Favorable Under Certain Scenarios

“The scenarios predicted by our models are encouraging in that there are clear actions that humans can take to improve the chances that healthy polar...

Read Article
link

Observing Polar Bears from Space

Monitoring wildlife in the Arctic is difficult. Study areas are cold, barren and often inaccessible. For decades scientists have struggled to study...

Read Article

Science and Products

  • Science
    link
    A polar bear walks across rubble ice in the Alaska portion of the southern Beaufort Sea

    Q&A: Recent Research on Southern Beaufort Sea Polar Bears

    Polar bears are found throughout the circumpolar Arctic and roam across miles of sea ice and land. There are 19 recognized subpopulations of polar bears across the Arctic with two in Alaska: the Chukchi Sea and the Southern Beaufort Sea. The sea ice habitat of these subpopulations is changing with substantial recent declines in the extent of sea ice off the coast of Alaska. These changes are...
    By
    Alaska Science Center
    link

    Q&A: Recent Research on Southern Beaufort Sea Polar Bears

    Polar bears are found throughout the circumpolar Arctic and roam across miles of sea ice and land. There are 19 recognized subpopulations of polar bears across the Arctic with two in Alaska: the Chukchi Sea and the Southern Beaufort Sea. The sea ice habitat of these subpopulations is changing with substantial recent declines in the extent of sea ice off the coast of Alaska. These changes are...
    Learn More
    link
    Female and two cubs polar bears on the sea ice

    Polar Bear Maternal Denning

    Pregnant polar bears enter maternity dens in October/November, give birth to cubs in December/January, and exit dens in March/April. Historically, most polar bears from the Southern Beaufort Sea (SBS) population constructed maternity dens on the sea ice. Over the last three decades, as sea ice has become thinner and prone to fragmentation, there has been a landward shift in the distribution of...
    By
    Species Management Research Program, Alaska Science Center
    link

    Polar Bear Maternal Denning

    Pregnant polar bears enter maternity dens in October/November, give birth to cubs in December/January, and exit dens in March/April. Historically, most polar bears from the Southern Beaufort Sea (SBS) population constructed maternity dens on the sea ice. Over the last three decades, as sea ice has become thinner and prone to fragmentation, there has been a landward shift in the distribution of...
    Learn More
    link
    Polar bear appears to walk on top of rippled gray water. Just behind it are very large breaking waves below a gray-blue sky.

    Polar Bear 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...
    By
    Species Management Research Program, Alaska Science Center
    link

    Polar Bear 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...
    Learn More
    link
    A polar bear walks across rubble ice in the Alaska portion of the southern Beaufort Sea

    Distribution and Movements of Polar Bears

    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...
    By
    Species Management Research Program, Alaska Science Center
    link

    Distribution and Movements of Polar Bears

    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...
    Learn More
    link
    Polar bear still hunting at a seal breathing hole

    Health and Energetics of Polar Bears

    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...
    By
    Species Management Research Program, Alaska Science Center
    link

    Health and Energetics of Polar Bears

    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...
    Learn More
    link
    Polar bear mother and two cubs on the Beaufort Sea ice.

    Polar Bear Research

    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...
    By
    Ecosystems, Land Management Research Program, Species Management Research Program, Alaska Science Center
    link

    Polar Bear Research

    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...
    Learn More
  • Data
    Filter Total Items: 14

    Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017

    his 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
    By
    Alaska Science Center

    Genetic structure of American black bear populations in the American Southwest and northern Mexico, 1994-2014

    Microsatellite genotypes for American black bears collected by Gould et al. 2002 and used to assess the genetic structure of American black bear populations in the American Southwest and northern Mexico. Genotypes are for Ursus americanus individuals.
    By
    Northern Rocky Mountain Science Center

    Polar Bear Fall Coastal Survey Data from the Southern Beaufort Sea of Alaska, 2010-2013

    This data set is one table with observations of polar bears located during aerial surveys along the coast and barrier islands of the southern Beaufort Seas during fall, 2010-2013. Survey flights were conducted using A-Star B2 and Bell 206 helicopters at an average altitude of 300 feet AGL and an average speed of 50 miles per hour. Survey crews searched for polar bears using coastal and inland tran
    By
    Alaska Science Center

    Mapping data of Polar Bear (Ursus maritimus) maternal den habitat, Arctic Coastal Plain, Alaska

    These are geospatial data that characterize the distribution of polar bear denning habitat on the National Petroleum Reserve-Alaska (NPR-A), the 1002 Area of the Arctic National Wildlife Refuge and the coastal plain of northern Alaska between the Colville River and the Alaska/Canada border.
    By
    Alaska Science Center

    Pathogen and Contaminant Exposure Data from Southern Beaufort Sea Polar Bears, 2007-2014

    These were data collected from polar bears from the Southern Beaufort Sea during the spring between 2007 and 2014. Data include individual ID, capture date, sex and age class, whether individuals visited bowhead whale carrion sites, exposure status relative to five pathogens, and concentrations of certain persistent organic pollutants.
    By
    Alaska Science Center

    Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Southern Beaufort Sea, 1986-2016

    This dataset consists of one table with predicted locations of adult female polar bears. Locations were derived by a Continuous Time-Correlated Random Walk (CTCRW) model using satellite tracking radio-collared adult female polar bears captured and instrumented in the southern Beaufort Sea, 1986–2016.
    By
    Alaska Science Center

    Innate Immunity and Stress and Reproductive Hormone Metrics for Southern Beaufort Sea Polar Bears, 2013-2015

    These were data collected from polar bears from the Southern Beaufort Sea during the spring between 2013 and 2015. Data include individual identification, demographic characteristics, year, status for the current and prior year regarding use of land, concentrations of stress response and reproductive hormones, blood-based biomarker measures indicative of fasting, body mass index, and body conditio
    By
    Alaska Science Center

    Serum Urea and Creatinine Levels of Spring-Caught Polar Bears (Ursus maritimus) in the Southern Beaufort and Chukchi Seas

    These 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
    By
    Alaska Science Center

    Multistate capture and search data from the southern Beaufort Sea polar bear population in Alaska, 2001-2016

    This data release contains two tables of information on polar bear distributions in the southern Beaufort Sea during spring, from 2001 to 2016. One table provides location (classified into 5 broad regions) of individual bears during the spring. The other table presents the aerial search effort by year and area.
    By
    Alaska Science Center

    Polar Bear Microsatellite Data Southern Beaufort Sea 2010-2013

    This data set provides Polar Bear microsatellite genotypes derived from twenty loci (G1A, G10B, G10C, CXX110, G1D, G10H, G10J, G10L, G10M, MSUT2, MU59, G10P, 145P07, CPH9, CXX20, MU50, MU51, G10X, CXX173, G10U). Samples for microsatellite genetic analysis were collected from polar bears from the southern Beaufort Sea during the spring and fall, 2010-2013. Tissue samples were collected from capture
    By
    Alaska Science Center

    Satellite Location and Tri-axial Accelerometer Data from Adult Female Polar Bears (Ursus maritimus) in the Southern Beaufort Sea, April-October 2014

    These data are from 5 adult female polar bears instrumented in the southern Beaufort Sea, April to October 2014. The dataset is comprised of two data packages: 1) contains GPS and Argos locations collected by satellite-linked GPS receivers mounted on external collars, and 2) contains archival logger data including measures of tri-axial acceleration and conductivity. These data were collected to ga
    By
    Alaska Science Center

    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

    This dataset contains a select subset of Argos and GPS locations collected by satellite data collection systems from collared adult female polar bears that were instrumented in the southern Beaufort Sea between 1985-2015. These data were collected to gain insights into movements of southern Beaufort Sea polar bears. These data were collected from adult female polar bears who had dependent young at
    By
    Alaska Science Center
  • Multimedia
    Graphical abstract showing role of diet and food intake affecting polar bear population dynamics in southern Beaufort Sea.
    link
    Scientist talking with students participating in 2022 Brown University Environmental Leadership Lab.
    link
  • Publications
    Filter Total Items: 69

    Efficacy of bear spray as a deterrent against polar bears

    Although there have been few attempts to systematically analyze information on the use of deterrents on polar bears (Ursus maritimus), understanding their effectiveness in mitigating human-polar bear conflicts is critical to ensuring both human safety and polar bear conservation. To fill this knowledge gap, we analyzed 19 incidents involving the use of bear spray on free-ranging polar bears from 1
    By
    Ecosystems, Alaska Science Center

    Observed and forecasted changes in land use by polar bears in the Beaufort and Chukchi Seas, 1985–2040

    Monitoring 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
    By
    Ecosystems, Alaska Science Center

    A serological survey of Francisella tularensis exposure in wildlife on the Arctic Coastal Plain of Alaska

    Tularemia is an infectious zoonotic disease caused by one of several subspecies of Francisella tularensis bacteria. Infections by F. tularensis are common throughout the northern hemisphere and have been detected in more than 250 wildlife species. In Alaska, US, where the pathogen was first identified in 1938, studies have identified F. tularensis antibodies in a diverse suite of taxa, including i
    By
    Ecosystems, Alaska Science Center

    Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics

    Sea 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
    By
    Ecosystems, Alaska Science Center, Fort Collins Science Center

    Modeling the spatial and temporal dynamics of land-based polar bear denning in Alaska

    Although polar bears (Ursus maritimus) of the Southern Beaufort Sea (SBS) subpopulation have commonly created maternal dens on sea ice in the past, maternal dens on land have become increasingly prevalent as sea ice declines. This trend creates conditions for increased human–bear interactions associated with local communities and industrial activity. Maternal denning is a vulnerable period in the
    By
    Ecosystems, Alaska Science Center

    Comparisons of Coupled Model Intercomparison Project Phase 5 (CMIP5) and Coupled Model Intercomparison Project Phase 6 (CMIP6) sea-ice projections in polar bear (Ursus maritimus) ecoregions during the 21st century

    Climate model projections are commonly used to assess potential impacts of global warming on a breadth of social, economic, and environmental topics. Modeling centers throughout the world coordinate to apply a consistent suite of radiative forcing experiments so that all model outputs can be collectively analyzed and compared. Three generations of model outputs have been produced and made availabl
    By
    Ecosystems, Alaska Science Center

    Using in situ/ex situ research collaborations to support polar bear conservation

    A warming Arctic threatens the long-term persistence of polar bears (Ursus maritimus) in the wild. Historically, little collaboration existed between the in situ and ex situ polar bear scientific communities. However, for the past decade, zoo professionals, government agencies, and non-governmental organizations (NGO’s) have partnered to leverage resources and expertise with the goal of addressing
    By
    Ecosystems, Alaska Science Center

    The ice don’t lie

    No abstract available.
    By
    Ecosystems, Alaska Science Center

    Evaluating the efficacy of aerial infrared surveys to detect artificial polar bear dens

    The need to balance economic development with impacts to Arctic wildlife has been a prominent subject since petroleum exploration began on the North Slope of Alaska, USA, in the late 1950s. The North Slope region includes polar bears (Ursus maritimus) of the southern Beaufort Sea subpopulation, which has experienced a long-term decline in abundance. Pregnant polar bears dig dens in snow drifts dur
    By
    Ecosystems, Alaska Science Center

    Marine mammal hotspots across the circumpolar Arctic

    AimIdentify hotspots and areas of high species richness for Arctic marine mammals.LocationCircumpolar Arctic.MethodsA total of 2115 biologging devices were deployed on marine mammals from 13 species in the Arctic from 2005 to 2019. Getis-Ord Gi* hotspots were calculated based on the number of individuals in grid cells for each species and for phylogenetic groups (nine pinnipeds, three cetaceans, a
    By
    Ecosystems, Land Management Research Program, Alaska Science Center

    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
    By
    Ecosystems, Alaska Science Center

    Distinct gut microbiomes in two polar bear subpopulations inhabiting different sea ice ecoregions

    Gut microbiomes were analyzed by 16S rRNA gene metabarcoding for polar bears (Ursus maritimus) from the southern Beaufort Sea (SB), where sea ice loss has led to increased use of land-based food resources by bears, and from East Greenland (EG), where persistent sea ice has allowed hunting of ice-associated prey nearly year-round. SB polar bears showed a higher number of total (940 vs. 742) and uni
    By
    Ecosystems, Alaska Science Center

    Non-USGS Publications**

    Algeo, T. P., D. Slate, R. M. Caron, T. C. Atwood, S. Recuenco, M. Ducey, R. B. Chipman, and M. Palace. 2017. Modeling raccoon (Procyon lotor) habitat connectivity to identify potential corridors for rabies spread. Tropical Medicine and Infectious Diseases 44. doi:10.3390/tropicalmed203044.
    Atwood, T. C., E. Peacock, K. M. Lillie, R. R. Wilson, and S. Miller. 2015. Demographic composition and behavior of polar bears summering on shore in Alaska. USGS Administrative Report, 26 p.
    Beasley, J. C., T. C. Atwood, M. E. Byrne, K. C. VerCauteren, S. R. Johnson, and O. E. Rhodes, Jr. 2015. A behaviorally-explicit approach for evaluating vaccine baits to mesopredators to control epizootics in fragmented landscapes. PLoS One 10:e0113206. doi:10.1371/journal.pone.0113206.
    Anderson, A., S. A. Shwiff, R. B. Chipman, T. C. Atwood, T. Cozzens, F. Fillo, R. Hale, B. Hatch, J. Maki, O. E. Rhodes, Jr, E. E. Rees, C. E. Rupprecht, R. Tinline, K. C. VerCauteren, and D. Slate. 2014. Forecasting the spread of raccoon rabies using a purpose-specific group decision-making process. Human-Wildlife Interactions 8(1):130-138.
    Slate, D., R. B. Chipman, T. P. Algeo, S. A. Mills, K. M. Nelson, C. K. Croson, E. J. Dubovi, R. W. Renshaw, K. C. VerCauteren, T. C. Atwood, S. Johnson, and C. E. Rupprecht. 2014. Safety and immunogenicity in the first field trial with ONRAB in raccoons in the United States. Journal of Wildlife Diseases 50(3):582-595. doi:10.7589/2013-08-207.
    Kunkel, K. E., T. K. Ruth, T. C. Atwood, D. H. Pletscher, and M. G. Hornocker. 2013. Assessing the value of wolves and cougars as conservation surrogates by linking carnivore hunting success with landscape characteristics. Animal Conservation 16:32-40. doi:10.1111/j.1469-1795.2012.00568.x.
    Beasley, J. D., W. S. Beatty, T. C. Atwood, S. Johnson, and O. E. Rhodes, Jr. 2012. A comparison of methods for estimating raccoon abundance: Implications for disease vaccination programs. Journal of Wildlife Management 76(6):1290-1297. doi:10.1002/jwmg.379.
    Atwood, T. C. and S. W. Breck. 2012. Carnivores, Conflict, and Conservation: Defining the Landscape of Conflict. Pages 99-118 in F. I. Álvares and G. E. Mata, (eds.). Carnivores: Species, Conservation, and Management. Nova Publishers.
    Atwood, T. C., T. L. Fry, and B. R. Leland. 2011. Partitioning of a limited resource by sympatric carnivores in the Chihuahuan Desert and the implications for disease transmission. Journal of Wildlife Management 75:1609-1615.
    Atwood, T. C., J. K. Young, J. P. Beckmann, S. W. Breck, O. E. Rhodes, Jr, J. A. Fike, and K. D. Bristow. 2011. Modeling connectivity of black bears in a desert sky island archipelago. Biological Conservation 144(12):2851-2862. doi:10.1016/j.biocon.2011.08.002.
    Fry, T. L., T. C. Atwood, and M. R. Dunbar. 2010. Utility of rhodamine B as a biomarker in raccoons. Human-Wildlife Interactions 4:275-282.
    Atwood, T. C. and E. M. Gese. 2010. Importance of resource selection and social behaviour to partitioning of hostile space by sympatric canids. Journal of Mammalogy 91:490-499.
    Atwood, T. C., T. J. DeLiberto, H. J. Smith, J. Stevenson, and K. C. VerCauteren. 2009. Raccoon spatial ecology related to cattle and bovine tuberculosis. Journal of Wildlife Management 73:647-654.
    Atwood, T. C., E. M. Gese, and K. E. Kunkel. 2009. Spatial decomposition of predation risk in a multiple-predator multiple-prey system. Journal of Wildlife Management 73:876-884.
    Atwood, T. C. and E. M. Gese. 2008. Coyotes (Canis latrans) and recolonizing wolves (Canis lupus): Social rank mediates risk-conditional behaviour at ungulate carcasses. Animal Behaviour 75:753-762.
    VerCauteren, K. C., T. C. Atwood, T. J. DeLiberto, H. J. Smith, J. Stevenson, T. Gidlewski, and B. V. Thomsen. 2008. Sentinel-based surveillance of coyotes to detect bovine tuberculosis in Michigan. Emerging Infectious Diseases 14:1862-1869.
    Atwood, T. C., K. C. VerCauteren, T. J. DeLiberto, H. J. Smith, and J. Stevenson. 2007. Coyotes as a potential sentinel species to detect bovine tuberculosis (Mycobacterium bovis) infection in white-tailed deer in Michigan. Journal of Wildlife Management 71:1545-1554.
    Atwood, T. C., E. M. Gese, and K. E. Kunkel. 2007. Comparative patterns of predation by cougars and recolonizing wolves. Journal of Wildlife Management 71:1098-1106.
    Atwood, T. C. 2006. The influence of habitat patch attributes on coyote group size and interaction in a fragmented landscape. Canadian Journal of Zoology 84:80-87.
    Atwood, T. C. 2006. Behavioral interactions between wolves, Canis lupus, and coyotes, Canis latrans, at ungulate carcasses in southwest Montana. Western North American Naturalist 66:390-394.
    Atwood, T. C., H. P. Weeks, Jr., and T. M. Gehring. 2004. Spatial ecology of coyotes along a suburban-to-rural gradient. Journal of Wildlife Management 85:1000-1009.
    Swihart, R. K., T. C. Atwood, J. R. Goheen, D. A. Scheiman, K. E. Munroe, and T. M. Gehring. 2003. Patch occupancy in North American mammals: Is patchiness in the eye of the beholder? . Journal of Biogeography 30:1259-1279.
    Atwood, T. C. and H. P. Weeks, Jr.. 2003. Sex-specific patterns of mineral lick preference in white-tailed deer. Northeastern Naturalist 10:409-414.
    Atwood, T. C. and H. P. Weeks, Jr.. 2002. Sex- and age-specific patterns of mineral lick use by white-tailed deer. American Midland Naturalist 148:289-296.
    Atwood, T. C. and H. P. Weeks, Jr.. 2002. Facultative dyad formation in adult male coyotes. Northeastern Naturalist 9:353-358.

    **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.

  • News
    link

    Polar Bear Outlook Favorable Under Certain Scenarios

    “The scenarios predicted by our models are encouraging in that there are clear actions that humans can take to improve the chances that healthy polar...

    Read Article
    link

    Observing Polar Bears from Space

    Monitoring wildlife in the Arctic is difficult. Study areas are cold, barren and often inaccessible. For decades scientists have struggled to study...

    Read Article

*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