, Volume 191, Issue 2, pp 311–323 | Cite as

Experimental increase in predation risk causes a cascading stress response in free-ranging snowshoe hares

  • Melanie R. BoudreauEmail author
  • Jacob L. Seguin
  • Rudy Boonstra
  • Rupert Palme
  • Stan Boutin
  • Charles J. Krebs
  • Dennis L. Murray
Physiological ecology – original research


Extensive research confirms that environmental stressors like predation risk can profoundly affect animal condition and physiology. However, there is a lack of experimental research assessing the suite of physiological responses to risk that may arise under realistic field conditions, leaving a fragmented picture of risk-related physiological change and potential downstream consequences on individuals. We increased predation risk in free-ranging snowshoe hares (Lepus americanus) during two consecutive summers by simulating natural chases using a model predator and monitored hares intensively via radio-telemetry and physiological assays, including measures designed to assess changes in stress physiology and overall condition. Compared to controls, risk-augmented hares had 25.8% higher free plasma cortisol, 15.9% lower cortisol-binding capacity, a greater neutrophil:lymphocyte skew, and a 10.4% increase in glucose. Despite these changes, intra-annual changes in two distinct condition indices, were unaffected by risk exposure. We infer risk-augmented hares compensated for changes in their stress physiology through either compensatory foraging and/or metabolic changes, which allowed them to have comparable condition to controls. Although differences between controls and risk-augmented hares were consistent each year, both groups had heightened stress measures during the second summer, likely reflecting an increase in natural stressors (i.e., predators) in the environment. We show that increased predation risk in free-ranging animals can profoundly alter stress physiology and that compensatory responses may contribute to limiting effects of such changes on condition. Ultimately, our results also highlight the importance of biologically relevant experimental risk manipulations in the wild as a means of assessing physiological responses to natural stressors.


Lepus americanus Cortisol Field experiment Hormone challenges 



We are grateful to JD, our science dog. We would also like to thank R. Lamoureux for field assistance, S. Lavergne, C. Bosson and B. Delehanty, for their guidance with the physiology lab work and A. Kenney for database assistance. We appreciate Kluane First Nation and Champagne-Aishihik First Nations for allowing us to work on their land. This research was funded by the Natural Sciences and Engineering Research Council of Canada, Ontario Graduate Scholarship, Northern Studies Training Program and the Canada Research Chairs program.

Author contribution statement

MRB, JLS and DLM conceived and designed the experiments. MRB and JLS performed the field experiments while MRB, JLS, RB and RP performed the laboratory work. MRB analyzed the data and MRB and DLM wrote the manuscript; all authors provided editorial advice.


  1. Barcellos LJG, Ritter F, Kreutz LC, Quevedo RM, da Silva LB, Bedin AC, Finco J, Cericato L (2007) Whole-body cortisol increases after direct and visual contact with a predator in zebrafish, Danio rerio. Aquaculture 272(1):774–778. CrossRefGoogle Scholar
  2. Boonstra R (2013) Reality as the leading cause of stress: rethinking the impact of chronic stress in nature. Funct Ecol 27(1):11–23. CrossRefGoogle Scholar
  3. Boonstra R, Singleton GR (1993) Population declines in the snowshoe hare and the role of stress. Gen Comp Endocrinol 91(2):126–143. CrossRefPubMedGoogle Scholar
  4. Boonstra R, Hik D, Singleton G, Tinnikov A (1998) The impact of predator-induced stress on the snowshoe hare cycle. Ecol Monogr 79(5):371–394.;2 CrossRefGoogle Scholar
  5. Boutin S, Krebs CJ, Boonstra R, Dale MRT, Hannon SJ, Martin K, Byrom A (1995) Population changes of the vertebrate community during a snowshoe hare cycle in Canada’s boreal forest. Oikos 74(1):69–80. CrossRefGoogle Scholar
  6. Breuner CW, Orchinik M (2002) Plasma binding proteins as mediators of corticosteroid action in vertebrates. J Endocrinol 175:99–112. CrossRefPubMedGoogle Scholar
  7. Breuner CW, Lynn SE, Julian GE, Cornelius JM, Heidinger BJ, Love OP, Whitman BA (2006) Plasma-binding globulins and acute stress response. Hormone Metab Res. 38(4):260–268 CrossRefPubMedGoogle Scholar
  8. CEMP: Community Ecological Monitoring Program (2017) Dataset Accessed: May 2018
  9. Clinchy M, Zanette L, Charlier TD, Newman AE, Schmidt KL, Boonstra R, Soma KK (2011) Multiple measures elucidate glucocorticoid responses to environmental variation in predation threat. Oecologia 166(3):607–614. CrossRefPubMedGoogle Scholar
  10. Clinchy M, Sheriff MJ, Zanette LY (2013) Predator-induced stress and the ecology of fear. Funct Ecol 27(1):56–65. CrossRefGoogle Scholar
  11. Costello DM, Michel MJ (2013) Predator-induced defenses in tadpoles confound body stoichiometry predictions of the general stress paradigm. Ecology 94(10):2229–2236. CrossRefPubMedGoogle Scholar
  12. Creel S, Christianson D, Liley S, Winnie JA (2007) Predation risk affects reproductive physiology and demography of elk. Science 315(5814):960. CrossRefPubMedGoogle Scholar
  13. Daly M, Behrends PR, Wilson MI, Jacobs LF (1992) Behavioural modulation of predation risk: moonlight avoidance and crepuscular compensation in a nocturnal desert rodent, Dipodomys merriami. Anim Behav 44(1):1–9CrossRefGoogle Scholar
  14. Dawson RD, Bortolotti GR (1997) Are avian hematocrits indicative of condition? American kestrels as a model. J Wildl Manag 61(4):1297–1306. CrossRefGoogle Scholar
  15. Delehanty B, Boonstra R (2011) Coping with intense reproductive aggression in male arctic ground squirrels: the stress axis and its signature tell divergent stories. Physiol Biochem Zool 84(4):417–428. CrossRefPubMedGoogle Scholar
  16. Eilam D, Dayan T, Ben-Eliyahu S, Schulman I, Shefer G, Hendrie CA (1999) Differential behavioural and hormonal responses of voles and spiny mice to owl calls. Anim Behav 58(5):1085–1093. CrossRefPubMedGoogle Scholar
  17. Environment Canada (2017) Canadian monthly climate data and 1981–2010 normals: Burwash A, Yukon Territory. Ottawa, Ontario. Accessed Jan 2017
  18. Fast MD, Hosoya S, Johnson SC, Afonso LO (2008) Cortisol response and immune-related effects of Atlantic salmon (Salmo salar Linnaeus) subjected to short-and long-term stress. Fish Shellfish Immunol 24(2):194–204. CrossRefPubMedGoogle Scholar
  19. Franzmann AW, Leresche RE (1978) Alaskan moose blood studies with emphasis on condition evaluation. J Wildl Manag 42(2):334–351. CrossRefGoogle Scholar
  20. Goymann W (2012) On the use of non-invasive hormone research in uncontrolled, natural environments: the problem with sex, diet, metabolic rate and the individual. Methods Ecol Evol 3(4):757–765. CrossRefGoogle Scholar
  21. Griffin PC, Griffin SC, Waroquiers C, Mills LS (2005) Mortality by moonlight: predation risk and the snowshoe hare. Behav Ecol 16(5):938–944. CrossRefGoogle Scholar
  22. Harrington DP, Fleming TR (1982) A class of rank test procedures for censored survival data. Biometrika 69(3):553–566. CrossRefGoogle Scholar
  23. Hawlena D, Schmitz OJ (2010) Physiological stress as a fundamental mechanism linking predation to ecosystem functioning. Am Nat 176(5):537–556. CrossRefPubMedGoogle Scholar
  24. Hellegren EC, Rogers LL, Seal US (1993) Serum chemistry and hematology of black bears: physiological indices of habitat quality or seasonal patterns? J Mammal 74(2):304–315. CrossRefGoogle Scholar
  25. Hik DS, McColl CJ, Boonstra R (2001) Why are Arctic ground squirrels more stressed in the boreal forest than in alpine meadows? Ecoscience 8(3):275–288. CrossRefGoogle Scholar
  26. Hinam HL, St.Clair CC (2008) High levels of habitat loss and fragmentation limit reproductive success by reducing home range size and provisioning rates of Northern saw-whet owls. Biol Conserv 141(2):524–535. CrossRefGoogle Scholar
  27. Hodges KE, Stefan CI, Gillis EA (1999) Does body condition affect fecundity in a cyclic population of snowshoe hares? Can J Zool 77(1):1–6. CrossRefGoogle Scholar
  28. Hodges KE, Krebs CJ, Hik DS, Stefan CI, Gillis EA, Doyle CE (2001) Snowshoe hare demography. In: Krebs CJ, Boutin S, Boonstra R (eds) Ecosystem dynamics of the boreal forest: the kluane project. Oxford University Press, New York, pp 141–178. CrossRefGoogle Scholar
  29. Hossie TJ, Landolt K, Murray DL (2017) Determinants and co-expression of anti-predator responses in amphibian tadpoles: a meta-analysis. Oikos 126(2):173–184. CrossRefGoogle Scholar
  30. Janssens L, Stoks R (2013) Predation risk causes oxidative damage in prey. Biol Lett 9(4):20130350. CrossRefPubMedPubMedCentralGoogle Scholar
  31. Kagawa N, Ryo K, Mugiya Y (1999) Enhanced expression of stress protein 70 in the brains of goldfish, Carassius auratus, reared with bluegills, Lepomis macrochirus. Fish Physiol Biochem 21(2):103–110. CrossRefGoogle Scholar
  32. Keith LB, Meslow EC, Rongstad OJ (1968) Techniques for snowshoe hare population studies. J Wildl Manag 32(4):801–812. CrossRefGoogle Scholar
  33. Korpimäki E, Krebs CJ (1996) Predation and population cycles of small mammals. Bioscience 46(10):754–764. CrossRefGoogle Scholar
  34. Krebs CJ, Boutin S, Boonstra R (2001) Ecosystem dynamics of the boreal forest: the Kluane project. Oxford University Press, New York. CrossRefGoogle Scholar
  35. Krebs CJ, Boonstra R, Kenney AJ, Gilbert BS (2018) Hares and small rodent cycles: a 45-year perspective on predator-prey dynamics in the Yukon boreal forest. Aust Zool. CrossRefGoogle Scholar
  36. Liesenjohann M, Liesenjohann T, Palme R, Eccard JA (2013) Differential behavioural and endocrine responses of common voles (Microtus arvalis) to nest predators and resource competitors. BMC Ecol 13:33. CrossRefPubMedPubMedCentralGoogle Scholar
  37. Lima SL, Dill LM (1990) Behavioral decisions made under the risk of predation: a review and prospectus. Can J Zool 68(4):619–640. CrossRefGoogle Scholar
  38. McPeek MA, Grace M, Richardson JM (2001) Physiological and behavioral responses to predators shape the growth/predation risk trade-off in damselflies. Ecology 82(6):1535–1545.;2 CrossRefGoogle Scholar
  39. Menge BA, Sutherland JP (1976) Species diversity gradients: synthesis of the roles of predation, competition, and temporal heterogeneity. Am Nat 110(973):351–369. CrossRefGoogle Scholar
  40. Miller WL, Tyrrell JB (1995) Endocrinology and metabolism. McGraw Hill, New York, pp 555–711Google Scholar
  41. Murray DL (2002) Differential body condition and vulnerability to predation in snowshoe hares. J Anim Ecol 71(4):614–625. CrossRefGoogle Scholar
  42. O’Donoghue MO, Boutin S, Krebs C, Zuleta G, Murray DL, Hofer EL (1998) Functional responses of coyotes and lynx to the snowshoe hare cycle. Ecology 79(4):1193–1208. CrossRefGoogle Scholar
  43. Oedekoven MA, Joern A (2000) Plant quality and spider predation affects grasshoppers (Acrididae): food-quality-dependent compensatory mortality. Ecology 81(1):66–77.;2 CrossRefGoogle Scholar
  44. Olejnik S, Algina J (2003) Generalized eta and omega squared statistics: measures of effect size for some common research designs. Psychol Methods 8(4):434–447. CrossRefPubMedGoogle Scholar
  45. Palme R, Möstl E (1997) Measurement of cortisol metabolites in feces of sheep as a parameter of cortisol concentration in the blood. Int J Mamm Biol 62(Supplement II):192–197Google Scholar
  46. Paul N, Novais SC, Lemos MF, Kunzmann A (2018) Chemical predator signals induce metabolic suppression in rock goby (Gobius paganellus). PLoS One 13(12):e0209286. CrossRefPubMedPubMedCentralGoogle Scholar
  47. Peckarsky BL, Abrams PA, Bolnick DI, Dill LM, Grabowski JH, Luttbeg B, Orrock JL, Peacor SD, Preisser EL, Schmitz OJ, Trussell GC (2008) Revisiting the classics: considering nonconsumptive effects in textbook examples of predator–prey interactions. Ecology 89(9):2416–2425. CrossRefPubMedGoogle Scholar
  48. Peers MJL, Majchrzak YN, Neilson E, Lamb CT, Hämäläinen A, Haines JA, Garland L, Doran-Myers D, Broadley K, Boonstra R, Boutin S (2018) Quantifying fear effects on prey demography in nature. Ecology 99(8):1716–1723. CrossRefPubMedGoogle Scholar
  49. Preisser E, Bolnick D, Bernard M (2005) Scared to death? The effects of intimidation and consumption in predator-prey interactions. Ecology 86(2):501–509. CrossRefGoogle Scholar
  50. R Core Team (2013) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria.
  51. Rollins-Smith LA (2017) Amphibian immunity–stress, disease, and climate change. Dev Comp Immunol 66:111–119. CrossRefPubMedGoogle Scholar
  52. Scheiner SM (2001) MANOVA: Multiple response variables and multispecies interactions. In Designs and analysis of ecological experiments (2nd ed.) Chapman & Hall, New York. pp 99–115Google Scholar
  53. Schmitt RJ, Holbrook SJ (1985) Patch selection by juvenile black surfperch (Embiotocidae) under variable risk: interactive influence of food quality and structural complexity. J Exp Mar Biol Ecol 85(3):269–285. CrossRefGoogle Scholar
  54. Seiter SA (2011) Predator presence suppresses immune function in a larval amphibian. Evolut Ecol Res 13(3):283–293Google Scholar
  55. Sheriff M, Krebs C, Boonstra R (2009a) The sensitive hare: sublethal effects of predator stress on reproduction in snowshoe hare. J Anim Ecol 78(6):1249–1258. CrossRefPubMedGoogle Scholar
  56. Sheriff MJ, Speakman JR, Kuchel L, Boutin S, Humphries MM (2009b) The cold shoulder: free-ranging snowshoe hares maintain a low cost of living in cold climates. Can J Zool 87(10):956–964. CrossRefGoogle Scholar
  57. Sheriff MJ, Krebs CJ, Boonstra R (2010) Assessing stress in animal populations: do fecal and plasma glucocorticoids tell the same story? Gen Compr Endocrinol 166(3):614–619. CrossRefGoogle Scholar
  58. Sheriff M, Krebs CJ, Boonstra R (2011) From process to pattern: how fluctuating predation risk impacts the stress axis of snowshoe hares during the 10-year cycle. Oecologia 166(3):593–605. CrossRefPubMedGoogle Scholar
  59. Sikes RS, Gannon WL and the Animal Care Use Committee of the American Society of Mammologists (2011) Guidelines of the American Society of Mammologists for the use of wild mammals in research. J Mammal 92(1):235–253. CrossRefGoogle Scholar
  60. Silverman MN, Sternberg EM (2012) Glucocorticoid regulation of inflammation and its functional correlates: from HPA axis to glucocorticoid receptor dysfunction. Ann N Y Acad Sci 1261(1):55–63. CrossRefPubMedPubMedCentralGoogle Scholar
  61. Sinclair AR, Krebs CJ, Smith JN, Boutin S (1988) Population biology of snowshoe hares. III. Nutrition, plant secondary compounds and food limitation. J Anim Ecol. 57(3):787–806. CrossRefGoogle Scholar
  62. Skelly DK, Kiesecker JM (2001) Venue and outcome in ecological experiments: manipulations of larval anurans. Oikos 94(1):198–208. CrossRefGoogle Scholar
  63. Slos S, Stoks R (2008) Predation risk induces stress proteins and reduces antioxidant defense. Funct Ecol 22(4):637–642. CrossRefGoogle Scholar
  64. Srivastava DS, Kolasa J, Bengtsson J, Gonzalez A, Lawler SP, Miller TE, Trzcinski MK (2004) Are natural microcosms useful model systems for ecology? Trends Ecol Evol 19(7):379–384. CrossRefPubMedGoogle Scholar
  65. Strobbe F, McPeek MA, De Block M, Stoks R (2010) Survival selection imposed by predation on a physiological trait underlying escape speed. Funct Ecol 24(6):1306–1312. CrossRefGoogle Scholar
  66. Sweitzer RA, Berger J (1992) Size-Related effects of predation on habitat use and behavior of porcupines (Erethizon Dorsatum). Ecology 73(3):867–875. CrossRefGoogle Scholar
  67. Thaler JS, McArt SH, Kaplan I (2012) Compensatory mechanisms for ameliorating the fundamental trade-off between predator avoidance and foraging. Proc Nat Acad Sci 109(30):12075–12080. CrossRefPubMedGoogle Scholar
  68. Trussell GC, Johnson AS, Rudolph SG, Gilfillan ES (1993) Resistance to dislodgement: habitat and size-specific differences in morphology and tenacity in an intertidal snail. Mar Ecol Prog Ser 100(1/2):135–144. CrossRefGoogle Scholar
  69. Turner MG (2010) Disturbance and landscape dynamics in a changing world. Ecology 91(10):2833–2849. CrossRefPubMedGoogle Scholar
  70. Van Dievel M, Janssens L, Stoks R (2016) Short-and long-term behavioural, physiological and stoichiometric responses to predation risk indicate chronic stress and compensatory mechanisms. Oecologia 181(2):347–357. CrossRefPubMedGoogle Scholar
  71. White PS, Jentsch A (2001) The search for generality in studies of disturbance and ecosystem dynamics. In: Progress in botany. Springer, Berlin. pp 399–450 CrossRefGoogle Scholar
  72. Woodley CM, Peterson MS (2003) Measuring responses to simulated predation threat using behavioral and physiological metrics: the role of aquatic vegetation. Oecologia 136(1):155–160. CrossRefPubMedGoogle Scholar
  73. Zanette LY, Clinchy M, Suraci JP (2014) Diagnosing predation risk effects on demography: can measuring physiology provide the means? Oecologia 176(3):637–651. CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Environmental and Life SciencesTrent UniversityPeterboroughCanada
  2. 2.Center for Neurobiology of StressUniversity of Toronto ScarboroughTorontoCanada
  3. 3.Department of Biomedical SciencesUniversity of Veterinary MedicineViennaAustria
  4. 4.Faculty of Science, 1-001 CCISUniversity of AlbertaEdmontonCanada
  5. 5.Department of ZoologyUniversity of British ColumbiaVancouverCanada

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