Polar Biology

, Volume 41, Issue 4, pp 773–780 | Cite as

Plasticity in physiological condition of female brown bears across diverse ecosystems

  • Grant V. HilderbrandEmail author
  • David D. Gustine
  • Buck Mangipane
  • Kyle Joly
  • William Leacock
  • Lindsey Mangipane
  • Joy Erlenbach
  • Mathew S. Sorum
  • Matthew D. Cameron
  • Jerrold L. Belant
  • Troy Cambier
Original Paper


Variation in life history strategies facilitates the near global distribution of mammals by expanding realized niche width. We investigated physiological plasticity in the spring body composition of adult female brown bears (Ursus arctos) across 4 diverse Alaskan ecosystems. Brown bears are a highly intelligent omnivore with a historic range spanning much of North America, Europe, and Asia. We hypothesized that body mass, fat mass, lean mass, and total caloric content would increase across populations with increasing food resource availability. Throughout their range, brown bears enter a period of torpor during winter months, decreasing their metabolic rate as an adaptation to this period of reduced food availability. They also give birth to and nourish offspring during this time. Due to this specific life history strategy, we further hypothesized that proportional body fat and the proportion of total calories derived from fat would be consistent across populations. Our results supported our first hypothesis: body, fat, and lean masses, and caloric content of bears across populations increased with the quality and abundance of available food. However, the proportional body fat content and proportion of calories from fat differed across populations indicating population-specific strategies to meet the demands of reduced seasonal food availability, offspring production and rearing, and climate as well as some plasticity to respond to environmental change or ecosystem perturbations. Investigations of body condition and energetics benefit from combined assessments of absolute, proportional, and caloric metrics to understand the nuances of brown bear physiological dynamics across and within populations.


Body composition Brown bear Energy Plasticity Ursus arctos 



We thank biologists W. Deacy and A. Morehouse, wildlife veterinarian J. Powers, and pilots A. Greenblatt, M. Keller, J. DeCreeft, R. Richotte, C. Cebulski, D. Welty, I. Bedingfield, K. Rees, K. VanHatten, and J. and J. Cummings for their assistance with animal capture and handling. N. Svoboda and three anonymous reviewers provided insightful comments and improved the manuscript. Funding was provided by the National Park Service, U.S. Fish and Wildlife Service, and U.S. Geological Survey. All procedures performed in studies involving animals were in accordance with the ethical standards of the institutions or practice at which the studies were conducted. Use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U. S. Government.


  1. Barboza PS, Parker KL (2008) Allocating protein to reproduction in Arctic reindeer and caribou. Physiol Biochem Zool 81:835–855CrossRefPubMedGoogle Scholar
  2. Bergmann C (1847) Über die verhältnisse der wärmeökonomie der thiere zu ihrer grösse. Göttinger Studien 3:595–708Google Scholar
  3. Bolnick DI, Svanback R, Fordyce JA, Yang LH, Davis JM, Hulsey CD, Forister ML (2003) The ecology of individuals: incidence and implications of individual specialization. Am Nat 161:1–28CrossRefPubMedGoogle Scholar
  4. Bowen WD, Iverson SJ, Boness DJ, Oftedal OT (2001) Foraging effort, food intake and lactation performance depend on maternal mass in a small phocid seal. Funct Ecol 15:325–334CrossRefGoogle Scholar
  5. Buck CL, Barnes BM (1999) Temperatures of hibernacula and changes in body composition of Arctic ground squirrels over winter. J Mamm 80:1264–1276CrossRefGoogle Scholar
  6. Cramer W et al (1999) Comparing global models of terrestrial net primary productivity (NPP): overview and key results. Glob Change Bio 5:1–15CrossRefGoogle Scholar
  7. Deacy W, Leacock W, Armstrong JB, Stanford JA (2016) Kodiak brown bears surf the salmon red wave: direct evidence from GPS collared individuals. Ecology 97:1091–1098CrossRefPubMedGoogle Scholar
  8. Erlenbach J, Rode KD, Raubenheimer D, Robbins CT (2014) Macronutrient optimization and energy maximization determines diets of brown bears. J Mamm 95:160–168CrossRefGoogle Scholar
  9. Farley SD, Robbins CT (1994) Development of two methods to estimate body composition of bears. Can J Zool 72:220–226CrossRefGoogle Scholar
  10. Farley SD, Robbins CT (1995) Lactation, hibernation, and mass dynamics of American black bears and grizzly bears. Can J Zool 73:2216–2222CrossRefGoogle Scholar
  11. Felicetti LA, Robbins CT, Shipley LA (2003) Dietary protein content alters energy expenditure and composition of the mass gain in grizzly bears (Ursus arctos horribilis). Physiol Biochem Zool 76:256–261CrossRefPubMedGoogle Scholar
  12. Fortin JK, Rode KD, Hilderbrand GV, Wilder J, Farley S, Jorgensen C, Marcot BG (2016) Impacts of human recreation on brown bears (Ursus arctos): a review and a new management tool. PLoS ONE 11:e0141983CrossRefPubMedPubMedCentralGoogle Scholar
  13. Gustine DD, Barboza PS, Lawler JP (2010) Dynamics of body protein and the implications for reproduction in captive muskoxen (Ovibos moschatus) during winter. Physiol Biochem Zool 83:687–697CrossRefPubMedGoogle Scholar
  14. Harlow HJ (1997) Winter body fat, food consumption and non-shivering thermogenesis of representative spontaneous and facultative hibernators: the white-tailed prairie dog and black-tailed prairie dog. J Therm Bio 22:21–30CrossRefGoogle Scholar
  15. Hertel AG, Bischof R, Langval O, Mysterud A, Kindberg J, Swenson JE, Zedrosser A (2017) Berry production drives bottom-up effects on body mass and reproductive success in an omnivore. Oikos. Google Scholar
  16. Hilderbrand GV (2017) Brown bear spring energetics, Alaska 2014–2016. U.S. Geological Survey data release.
  17. Hilderbrand GV, Golden HN (2013) Body composition of free-ranging wolves (Canis lupus). Can J Zool 91:1–6CrossRefGoogle Scholar
  18. Hilderbrand GV, Farley SD, Robbins CT (1998) Predicting body condition of bears via two field methods. J Wildl Manage 62:406–409CrossRefGoogle Scholar
  19. Hilderbrand GV, Jenkins SJ, Schwartz CC, Hanley TA, Robbins CT (1999a) Effect of seasonal differences in dietary meat intake on changes in body mass and composition in wild and captive brown bears. Can J Zool 77:1623–1630CrossRefGoogle Scholar
  20. Hilderbrand GV, Schwartz CC, Robbins CT, Jacoby ME, Hanley TA, Arthur SM, Servheen C (1999b) Importance of meat, particularly salmon, to body size, population productivity, and conservation of North American brown bears. Can J Zool 77:132–138CrossRefGoogle Scholar
  21. Hilderbrand GV, Schwartz CC, Robbins CT, Hanley TA (2000) Effect of hibernation and reproductive status on body mass and condition of coastal brown bears. J Wildl Manage 64:178–183CrossRefGoogle Scholar
  22. Hilderbrand GV, Gustine DD, Mangipane B, Joly K, Leacock W, Mangipane L, Erlenbach J, Sorum MS, Cameron MD, Belant JL, Cambier T (in press). Body size and lean mass of brown bears across and withing four diverse ecosystems. J ZoolGoogle Scholar
  23. Holm S (1979) A simple sequentially rejective multiple test procedure. Scand J Stat 6:65–70Google Scholar
  24. Hood WR, Oftedal OT, Kunz TH (2006) Variation in body composition of female big brown bats (Eptesicus fuscus) during lactation. J Comp Physiol B 176:807–819CrossRefPubMedGoogle Scholar
  25. Kuntz R, Kubalek C, Ruf T, Tataruch F, Arnold W (2006) Seasonal adjustment of energy budgets in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) I. Energy intake. J Exper Biol 209:4557–4565CrossRefGoogle Scholar
  26. Lafferty DJR, Belant JL, Phillips DL (2015) Testing the niche variation hypothesis with a measure of body condition. Oikos 124:732–740CrossRefGoogle Scholar
  27. Lesage L, Crête M, Huot J, Ouellet J (2001) Evidence for a trade-off between growth and body reserves in northern white-tailed deer. Oecologia 126:30–41CrossRefPubMedGoogle Scholar
  28. López-Alfaro C, Robbins CT, Zedrosser A, Nielsen SE (2013) Energetics of hibernation and reproductive trade-offs in brown bears. Ecol Model 270:1–10CrossRefGoogle Scholar
  29. Mangipane LS, Belant JL, Lafferty DJR, Gustine DD, Hiller TL, Colvin ME, Mangipane BA, Hilderbrand GV (2017) Dietary plasticity in a nutrient-rich system does not influence brown bear (Ursus arctos) body condition or denning. Polar Biol. Google Scholar
  30. Mellish JE, Iverson SJ, Bowen WD (1999) Variation in milk production and lactation performance in grey seals and consequences for pup growth and weaning characteristics. Physiol Biochem Zool 72:677–690CrossRefPubMedGoogle Scholar
  31. Monahan W B, Rosemartin A, Gerst K L, Fisichelli N A, Ault T, Schwartz M D, Gross J E, Weltzin J F (2016) Climate change is advancing spring onset across the U.S. National park system. Ecosphere 7(10):45.
  32. Monson DH, Estes JA, Bodkin JL, Siniff DB (2000) Life history plasticity and population regulation in sea otters. Oikos 90:457–468CrossRefGoogle Scholar
  33. Monteith KL, Stephenson TR, Bleich VC, Conner MM, Pierce BM, Bowyer RT (2013) Risk-sensitive allocation in seasonal dynamics of fat and protein reserves in a long-lived mammal. J Animal Ecol 82:377–388CrossRefGoogle Scholar
  34. Mowat G, Heard DC (2006) Major components of grizzly bear diet across North America. Can J Zool 84:473–489CrossRefGoogle Scholar
  35. Oftedal OT (2000) Use of maternal reserves as a lactation strategy in large mammals.”. Proc Nutr Soc 59:99–106CrossRefPubMedGoogle Scholar
  36. Pasitschniak-Arts M (1993) Mammalian Species: Ursus arctos. The Amer Soc Mammal 493:1–10Google Scholar
  37. Robbins CT (2001) Wildlife Feeding and Nutrition. Academic Press, San DiegoGoogle Scholar
  38. Robbins CT, Fortin JK, Rode KD, Farley SD, Shipley LA, Felicetti LA (2007) Optimizing protein intake as a foraging strategy to maximize mass gain in an omnivore. Oikos 116:1675–1682CrossRefGoogle Scholar
  39. Rode KD, Robbins CT (2000) Why bears consume mixed diets during fruit abundance. Can J Zool 78:1640–1645CrossRefGoogle Scholar
  40. Schwartz CC, Haroldson MA, White GC (2006) Survival of cub and yearling grizzly bears in the greater Yellowstone ecosystem, 1983–2002. Wildl Monographs 161:18–24Google Scholar
  41. Servheen C. 1999. Bear status survey and conservation action plan. IUCNGoogle Scholar
  42. Sidak Z (1967) Rectangular confidence region for the means of multivariate normal distributions. J Amer Stat Assoc 62:626–633Google Scholar
  43. Stanek AE, Wolf N, Hilderbrand GV, Mangipane B, Causey D, Welker JM (2017) Seasonal foraging strategies of Alaskan gray wolves in a salmon subsidized ecosystem. Can J Zool 95:555–563CrossRefGoogle Scholar
  44. Suring LH, Del Frate G (2002) Spatial analyses of locations of brown bears killed in defense of life or property on the Kenai Peninsula, Alaska, USA. Ursus 13:237–245Google Scholar
  45. Suring LH, Farley SD, Hilderbrand GV, Goldstein MI, Howlin S, Erickson WP (2006) Patterns of landscape use by female brown bears on the Kenai Peninsula, Alaska. J Wildl Manage 70:1580–1587CrossRefGoogle Scholar
  46. Taylor WP Jr, Reynolds HV III, Ballard WB (1989) Immobilization of grizzly bears with tiletamine hydrochloride and zolazepam hydrochloride. J Wildl Manage 53:978–981CrossRefGoogle Scholar
  47. Wilson RR, Gustine DD, Joly K (2014) Evaluating potential effects of an industrial road on winter habitat of caribou in north-central Alaska. Arctic 67:472–482CrossRefGoogle Scholar
  48. Winstanley RK, Buttemer WA, Saunders G (1999) Fat deposition and seasonal variation in body composition of red foxes (Vulpes vulpes) in Australia. Can J Zool 77:406–412CrossRefGoogle Scholar
  49. Zar JH (1999) Biostatistical analysis, 4th edn. Prentice Hall, Inc., New JerseyGoogle Scholar
  50. Zuercher GL, Roby DD, Rexstad EA (1999) Seasonal changes in body mass, composition, and organs of northern red-backed voles in interior Alaska. J Mamm 80:443–459CrossRefGoogle Scholar

Copyright information

© Springer 2018

Authors and Affiliations

  1. 1.U.S. Geological Survey, Alaska Science CenterAnchorageUSA
  2. 2.National Park Service, Grand Teton National ParkMooseUSA
  3. 3.National Park Service, Lake Clark National Park and PreservePort AlsworthUSA
  4. 4.National Park Service, Gates of the Arctic National Park and PreserveFairbanksUSA
  5. 5.U.S. Fish and Wildlife Service, Kodiak National Wildlife RefugeKodiakUSA
  6. 6.Carnivore Ecology Laboratory, Forest and Wildlife Research CenterMississippi State UniversityStarkvilleUSA
  7. 7.School of the EnvironmentWashington State UniversityPullmanUSA
  8. 8.Chena River AviationFairbanksUSA

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