, Volume 56, Issue 3, pp 259–272 | Cite as

Variation of hair cortisol concentrations among wild populations of two baboon species (Papio anubis, P. hamadryas) and a population of their natural hybrids

  • Nicolaas H. FourieEmail author
  • Clifford J. Jolly
  • Jane E. Phillips-Conroy
  • Janine L. Brown
  • Robin M. Bernstein
Original Article


Male olive (Papio anubis) and hamadryas (P. hamadryas) baboons have distinctive sociobehavioral and physical characteristics. In the Awash National Park, Ethiopia, a hybrid population at the contact zone between these two species, exhibits heterogeneous sociobehavioral and physical characteristics. The ambiguity of the hybrid social environment and disruption of parental stress genotypes may be sources of physiological stress for hybrids. We examined levels of chronic stress among males of the three populations and tested the prediction that chronic cortisol levels would be higher among the hybrids. Animals were captured, sampled, and released during the wet season, and a hair sample was taken for assay. Cortisol was extracted from 182 hair samples with methanol and quantified by ELISA. We included age, age class, rainfall variation, and species affiliation in models examining variation in hair cortisol levels. Species and age significantly contributed to models explaining variation in hair cortisol. Infant hypercortisolism was observed in all three groups, and a decline in cortisol through juvenile and adolescent stages, with a subsequent rise in adulthood. This rise occurred earliest in hamadryas, corroborating other evidence of the precocious development of hamadryas baboons. As expected, hybrids had significantly elevated hair cortisol compared with olive baboons and hamadryas, irrespective of age, except for very young animals. Infant hypercortisolism was also less pronounced among hybrids. Species differences and age-related differences in cortisol levels suggest a dysregulated cortisol phenotype in hybrids, and possibly reflect some form of hybrid disadvantage. More work will be required to disentangle the effects of genetic factors and the social environment.


Hair Cortisol Baboons Hybrids Behavior Stress 



We thank all those who participated in sample and data collection over the course of the Awash National Park Baboon Research Project, the Ethiopian Wildlife Conservation Organization, Addis Ababa University, the Awash National Park wardens and scouts, and many graduate students and Earthwatch volunteers. We acknowledge the Smithsonian’s Conservation Biology Institute’s Endocrinology Laboratory, in particular Nicole Presley and Sarah Putman for their friendly assistance and advice. Hair samples were collected during fieldwork conducted from 1993 to 2000 supported by the Earthwatch Institute, New York University, Washington University, the Harry Frank Guggenheim Foundation, and the National Science Foundation (NSFSRB9615150).

Ethical standard

The research was conducted with permission granted by successive General Managers of the Ethiopian Wildlife Conservation Organization, with the collaboration of Addis Ababa University, and with the invaluable practical assistance of the Wardens and Staff of the Awash National Park. Research protocols were approved by the Institutional Animal Care and Use Committees of Washington University and New York University, and all capture, sampling, and release procedures conducted in the field conformed with rules and regulations of the host country.

Supplementary material

10329_2015_469_MOESM1_ESM.docx (65 kb)
Supplementary material 1 (DOCX 65 kb)


  1. Abbott DH, Keverne EB, Bercovitch FB, Shively CA, Mendoza SP, Saltzman W, Snowdon CT, Ziegler TE, Banjevic M, Garland T, Sapolsky RM (2003) Are subordinates always stressed? A comparative analysis of rank differences in cortisol levels among primates. Horm Behav 43:67–82PubMedGoogle Scholar
  2. Abegglen JJ (1984) On socialization in Hamadryas Baboons: a field study. Associated University Presses, LondonGoogle Scholar
  3. Accorsi PA, Carloni E, Valsecchi P, Viggiani R, Gamberoni M, Tamanini C, Seren E (2008) Cortisol determination in hair and faeces from domestic cats and dogs. Gen Comp Endocrinol 155:398–402PubMedGoogle Scholar
  4. Ackermann RR, Rogers J, Cheverud JM (2006) Identifying the morphological signatures of hybridization in primate and human evolution. J Hum Evol 51:632–645PubMedGoogle Scholar
  5. Alberts SC, Sapolsky RM, Altmann J (1992) Behavioral, endocrine, and immunological correlates of immigration by an aggressive male into a natural primate group. Horm Behav 26:167–178PubMedGoogle Scholar
  6. Anestis SF, Bribiescas RG, Hasselschwert DL (2006) Age, rank, and personality effects on the cortisol sedation stress response in young chimpanzees. Physiol Behav 89:287–294PubMedGoogle Scholar
  7. Arnold ML, Hodges SA (1995) Are natural hybrids fit or unfit relative to their parents? Trends Ecol Evol 10:67–71PubMedGoogle Scholar
  8. Arnold ML, Sapir Y, Martin NH (2008) Review. Genetic exchange and the origin of adaptations: prokaryotes to primates. Philos Trans R Soc Lond B Biol Sci 363:2813–2820PubMedCentralPubMedGoogle Scholar
  9. Bachmann C, Kummer H (1980) Male assessment of female choice in hamadryas baboons. Behav Ecol Sociobiol 6:315–321Google Scholar
  10. Barton NH, Hewitt GM (1989) Adaptation, speciation and hybrid zones. Nature 341:497–503PubMedGoogle Scholar
  11. Bechshoft TO, Sonne C, Dietz R, Born EW, Novak MA, Henchey E, Meyer JS (2011) Cortisol levels in hair of East Greenland polar bears. Sci Total Environ 409:831–834PubMedCentralPubMedGoogle Scholar
  12. Behie AM, Pavelka MSM, Chapman CA (2010) Sources of variation in fecal cortisol levels in howler monkeys in Belize. Am J Primatol 72:600–606PubMedGoogle Scholar
  13. Bennett A, Hayssen V (2010) Measuring cortisol in hair and saliva from dogs: coat color and pigment differences. Domest Anim Endocrin 39:171–180Google Scholar
  14. Bergman TJ, Beehner JC (2004) Social system of a hybrid baboon group (Papio anubis × P. hamadryas). Int J Primatol 25:1313–1330Google Scholar
  15. Bergman TJ, Beehner JC, Cheney DL, Seyfarth RM, Whitten PL (2005) Correlates of stress in free-ranging male chacma baboons, Papio hamadryas ursinus. Anim Behav 70:703–713Google Scholar
  16. Bergman TJ, Phillips-Conroy JE, Jolly CJ (2008) Behavioral variation and reproductive success of male baboons (Papio anubis × Papio hamadryas) in a hybrid social group. Am J Primatol 70:136–147PubMedGoogle Scholar
  17. Bosse KA, Gieler U (1987) Seelische Faktoren bei Hautkrankheiten. Beiträge zur psychosomatischen Dermatologie. Verlag Hans Huber, BernGoogle Scholar
  18. Botchkarev VA (2003) Stress and the hair follicle: exploring the connections. Am J Pathol 162:709–712PubMedCentralPubMedGoogle Scholar
  19. Burke JM, Arnold ML (2001) Genetics and the fitness of hybrids. Annu Rev Genet 35:31–52PubMedGoogle Scholar
  20. Byung-Wan L, Jun H, Yim H-J, Park J-B, Woo H, Yoo H-J (2010) Dysfunctional pancreatic Î2-cells of critical stress play a more prominent role in the development of stress diabetes in critically burned Korean subjects. Metabolism 59:1307–1315PubMedGoogle Scholar
  21. Cannon WB (1914) The emergency function of the adrenal medulla in pain and the major emotions. Am J Physiol 33:356–393Google Scholar
  22. Carter C (1998) Neuroendocrine perspectives on social attachment and love. Psychoneuroendocrinology 23:779–818PubMedGoogle Scholar
  23. Castracane VD, Cutler GB, Loriaux DL (1981) Pubertal endocrinology of the baboon: adrenarche. Am J Physiol 241:305–309Google Scholar
  24. Cavigelli SA (1999) Behavioural patterns associated with faecal cortisol levels in free-ranging female ring-tailed lemurs, Lemur catta. Anim Behav 57:935–944PubMedGoogle Scholar
  25. Chen FS, Kumsta R, von Dawans B, Monakhov M, Ebstein RP, Heinrichs M (2011) Common oxytocin receptor gene (OXTR) polymorphism and social support interact to reduce stress in humans. Proc Natl Acad Sci 108:19937–19942PubMedCentralPubMedGoogle Scholar
  26. Chrousos GP (2000) Stress, chronic inflammation, and emotional and physical well-being: concurrent effects and chronic sequelae. J Allergy Clin Immunol 106:275–291Google Scholar
  27. Clara E, Tommasi L, Rogers L (2008) Social mobbing calls in common marmosets (Callithrix jacchus): effects of experience and associated cortisol levels. Anim Cogn 11:349–358PubMedGoogle Scholar
  28. Colmenares F (1990) Greeting behaviour in male baboons, I: communication, reciprocity and symmetry. Behaviour 113:81–116Google Scholar
  29. Colmenares F (1991) Greeting behaviour between male baboons: oestrous females, rivalry and negotiation. Anim Behav 41:49–60Google Scholar
  30. Crockett CM, Bowers CL, Sackett GP, Bowden DM (1993) Urinary cortisol responses of longtailed macaques to five cage sizes, tethering, sedation, and room change. Am J Primatol 30:55–74Google Scholar
  31. Crockford C, Wittig RM, Whitten PL, Seyfarth RM, Cheney DL (2008) Social stressors and coping mechanisms in wild female baboons (Papio hamadryas ursinus). Horm Behav 53:254–265PubMedGoogle Scholar
  32. Damsted SK, Born AP, Paulson OB, Uldall P (2011) Exogenous glucocorticoids and adverse cerebral effects in children. Eur J Paediatr Neurol 15:465–477PubMedGoogle Scholar
  33. Das R, Feuerstadt P, Brandt LJ (2010) Glucocorticoids are associated with increased risk of short-term mortality in hospitalized patients with clostridium difficile-associated disease. Am J Gastroenterol 105:2040–2049PubMedGoogle Scholar
  34. Davenport MD, Tiefenbacher S, Lutz CK, Novak MA, Meyer JS (2006) Analysis of endogenous cortisol concentrations in the hair of rhesus macaques. Gen Comp Endocrinol 147:255–261PubMedGoogle Scholar
  35. de Kloet ER, Oitzl MS, Joëls M (1999) Stress and cognition: are corticosteroids good or bad guys? Trends Neurosci 22:422–426PubMedGoogle Scholar
  36. Delehanty B, Boonstra R (2009) Impact of live trapping on stress profiles of Richardson’s ground squirrel (Spermophilus richardsonii). Gen Comp Endocrinol 160:176–182PubMedGoogle Scholar
  37. Delgiudice GD, Kyran E, Kunkel L, David M, Ulysses SS (1990) Minimizing capture-related stress on white-tailed deer with a capture collar. J Wild Manag 54:299–303Google Scholar
  38. Dettenborn L, Tietze A, Bruckner F, Kirschbaum C (2010) Higher cortisol content in hair among long-term unemployed individuals compared to controls. Psychoneuroendocrinology 35:1404–1409PubMedGoogle Scholar
  39. DeVries AC (2002) Interaction among social environment, the hypothalamic–pituitary–adrenal axis, and behavior. Horm Behav 41:405–413PubMedGoogle Scholar
  40. Dunbar RIM (1988) Primate Social Systems. Chapman and Hall, LondonGoogle Scholar
  41. Epel ES (2009) Psychological and metabolic stress: a recipe for accelerated cellular aging? Hormones 8:7–22PubMedGoogle Scholar
  42. Fairbanks LA, Jorgensen MJ, Bailey JN, Breidendal SE, Grzywa R, Laudenslager ML (2011) Heritability and genetic correlation of hair cortisol in vervet monkeys in low and higher stress environments. Psychoneuroendocrinology 36:1201–1208PubMedCentralPubMedGoogle Scholar
  43. Fourie NH, Bernstein RM (2011a) Hair cortisol levels track phylogenetic and age related differences in hypothalamic-pituitaryadrenal (HPA) axis activity in non-human primates. Gen Comp Endocrinol 174:150–155PubMedGoogle Scholar
  44. Fourie NH, Bernstein RM (2011b) Quantification of cortisol in wild and captive nonhuman primate hair: methodological considerations and biological validation. Am J Phys Anthropol 144:137Google Scholar
  45. Fraser O, Plowman AB (2007) Function of notification in Papio hamadryas? Int J Primatol 28:1439–1448Google Scholar
  46. Gerlai R (1996) Gene-targeting studies of mammalian behavior: is it the mutation or the background genotype? Trends Neurosci 19:177–181PubMedGoogle Scholar
  47. Gesquiere LR, Onyango PO, Alberts SC, Altmann J (2011) Endocrinology of year-round reproduction in a highly seasonal habitat: environmental variability in testosterone and glucocorticoids in baboon males. Am J Phys Anthropol 144:169–176PubMedCentralPubMedGoogle Scholar
  48. Gunnar MR, Gonzalez CA, Goodlin BL, Levine S (1981) Behavioral and pituitary-adrenal responses during a prolonged separation period in infant rhesus monkeys. Psychoneuroimmunology 6:65–75Google Scholar
  49. Hammond RL, Handley LJ, Winney BJ, Bruford MW, Perrin N (2006) Genetic evidence for female-biased dispersal and gene flow in a polygynous primate. Proc Royal Soc Biol Sci 273:479–484Google Scholar
  50. Heintz MR, Santymire RM, Parr LA, Lonsdorf EV (2011) Validation of a cortisol enzyme immunoassay and characterization of salivary cortisol circadian rhythm in chimpanzees (Pan troglodytes). Am J Primatol 73:903–908PubMedGoogle Scholar
  51. Hiller-Sturmhöfel S, Bartke A (1998) The endocrine system: an overview. Alcohol Health Res World 22:153–164PubMedGoogle Scholar
  52. Jaimez NA, Bribiescas RG, Aronsen GP, Anestis SA, Watts DP (2011) Urinary cortisol levels of gray-cheeked mangabeys are higher in disturbed compared to undisturbed forest areas in Kibale National Park Uganda. Anim Conserv 15:242–247Google Scholar
  53. Jolly CJ, Phillips-Conroy JE (2003) Testicular size, mating system, and maturation schedules in wild anubis and hamadryas baboons. Int J Primatol 24:125–142Google Scholar
  54. Jolly CJ, Phillips-Conroy JE, Kaplan JR, Mann JJ (2008) Cerebrospinal fluid monoaminergic metabolites in wild Papio anubis and P. hamadryas are concordant with taxon-specific behavioral ontogeny. Int J Primatol 29:1549–1566Google Scholar
  55. Jolly CJ, Phillips-Conroy JE, Kaplan JR, Mann JJ (2013) Monoamine neurotransmitter metabolites in the cerebrospinal fluid of a group of hybrid baboons (Papio hamadryas × P. anubis). Int J Primatol 34:836–858Google Scholar
  56. Kirschbaum C, Klauer T, Filipp S, Hellhammer D (1995) Sex-specific effects of social support on cortisol and subjective responses to acute psychological stress. Psychosom Med 57:23–31PubMedGoogle Scholar
  57. Koolhaas JM, Bartolomucci A, Buwalda B, de Boer SF, Flogge G, Korte SM, Meerlo P, Murison R, Olivier B, Palanza P, Richter-Levin G, Sgoifo A, Steimer T, Stiedl O, van Dijk G, Wohr M, Fuchs E (2011) Stress revisited: a critical evaluation of the stress concept. Neurosci Biobehav Rev 35:1291–1301PubMedGoogle Scholar
  58. Kummer H (1968) Social organisation of hamadryas baboons: a field study. University of Chicago Press, ChicagoGoogle Scholar
  59. Kummer H, Götz W, Angst W (1974) Triadic differentiation: an inhibitory process protecting pair bonds in baboons. Behaviour 49:62–87PubMedGoogle Scholar
  60. Lewis JG, Bagley CJ, Elder PA, Bachmann AW, Torpy DJ (2005) Plasma free cortisol fraction reflects levels of functioning corticosteroid-binding globulin. Clin Chim Acta 359:189–194PubMedGoogle Scholar
  61. Lieth H (1973) Primary production: terrestrial ecosystems. Hum Ecol 1:303–332Google Scholar
  62. Luckow A, Reifman A, Mclntosh DN (1998) Gender differences in coping: a meta-analysis. Poster session presented at the 106th Annual Convention of the American Psychological Association, San Francisco, CAGoogle Scholar
  63. Lynn SE, Porter AJ (2008) Trapping initiates stress response in breeding and non-breeding house sparrows Passer domesticus: implications for using unmonitored traps in field studies. J Avian Biol 39:87–94Google Scholar
  64. Macbeth BJ, Cattet MRL, Stenhouse GB, Gibeau ML, Janz DM (2010) Hair cortisol concentration as a noninvasive measure of long-term stress in free-ranging grizzly bears (Ursus arctos): considerations with implications for other wildlife. Can J Zool 88:935–949Google Scholar
  65. McConway MG, Chapman RS (1986) Development and evaluation of a simple, direct, solid-phase radioimmunoassay of serum cortisol from readily available reagents. Clin Chim Acta 158:59–70PubMedGoogle Scholar
  66. Munro CJ, Lasley BL (1988) Non-radiometric methods for immunoassay of steroid hormones. In: Albertson BD, Haseltine FP (eds) Non-radiometric assays: technology and application in polypeptide and steroid hormone detection. Alan R. Liss Inc., New York, pp 289–329Google Scholar
  67. Nagel U (1973) A comparison of anubis, hamadryas baboons and their hybdrids at a species border in Ethiopia. Folia Primatol 19:104–165PubMedGoogle Scholar
  68. Nijm J, Jonasson L (2009) Inflammation and cortisol response in coronary artery disease. Ann Med 41:224–233PubMedGoogle Scholar
  69. Nystrom PDA (1992) Mating Success of Hamadryas, Anubis and Hybrid Male Baboons in a “Mixed” Social Group in the Awash National Park, Ethiopia, PhD Thesis, Washington University, St. Louis, MOGoogle Scholar
  70. Peláez F (1982) Greeting movements among adult males in a colony of baboons: papio hamadryas, P. cynocephalus and their hybrids. Primates 23:233–244Google Scholar
  71. Peters EM, Arck PC, Paus R (2006) Hair growth inhibition by psychoemotional stress: a mouse model for neural mechanisms in hair growth control. Exp Dermatol 15:1–13PubMedGoogle Scholar
  72. Phillips-Conroy JE, Jolly CJ (1988) Dental eruption schedules of wild and captive baboons. Am J Primatol 15:17–29Google Scholar
  73. Phillips-Conroy JE, Bergman T, Jolly CJ (2000) Quantitative assessment of occlusal wear and age estimation in Ethiopian and Tanzanian baboons. In: Whitehead PF, Jolly CJ (eds) Old world mon keys. Cambridge University Press, Cambridge, pp 321–340Google Scholar
  74. Pines M, Saunders J, Swedell L (2011) Alternative routes to the leader male role in a multi-level society: follower vs. solitary male strategies and outcomes in hamadryas baboons. Am J Primatol 73:679–691PubMedGoogle Scholar
  75. Pusey AE, Packer C (1987) Philopatry and dispersal. In: Smuts BB, Cheney DL, Seyfarth RM, Struhsaker TT, Wrangham RW (eds) Primate Societies. University of Chicago Press, Chicago, pp 250–266Google Scholar
  76. Sapolsky RM (1986) Endocrine and behavioral correlates of drought in wild olive baboons (Papio anubis). Am J Primatol 11:217–227Google Scholar
  77. Sapolsky RM (1990) Adrenocortical function, social rank, and personality among wild baboons. Biol Psychiatry 15:862–878Google Scholar
  78. Sapolsky MR (1992) Stress, the aging brain and the mechanisms of neuron death. MIT Press, CambridgeGoogle Scholar
  79. Sapolsky RM (2000) Stress hormones: good and bad. Neurobiol Dis 7:540–542PubMedGoogle Scholar
  80. Sapolsky MR (2004) Why zebras don’t get ulcers: a guide to stress, stress related diseases and coping. WH Freeman, New YorkGoogle Scholar
  81. Sapolsky RM (2005) The influence of social hierarchy on primate health. Science 308:648–652PubMedGoogle Scholar
  82. Sapolsky RM, Altmann J (1991) Increase of hypercortisolism and dexamethasone resistance increase with age among wild baboons. Biol Psych 30:1008–1016Google Scholar
  83. Sapolsky MR, Alberts SC, Altmann J (1997) Hypercortisolism associated with social subordinance and social isolation among wild baboons. Arch Gen Psychiatry 54:1137–1143PubMedGoogle Scholar
  84. Satterthwaite FE (1946) An approximate distribution of estimates of variance components. Biometr Bull 2:110–114PubMedGoogle Scholar
  85. Sauve B, Koren G, Walsh G, Tokmakejian S, van Uum SHM (2007) Measurement of cortisol in human hair as a biomarker of systemic exposure. Clin Invest Med 30:E183–E191PubMedGoogle Scholar
  86. Schreier AL (2010) Feeding ecology, food availability and ranging patterns of wild hamadryas baboons in Filoha. Folia Primatol 81:129–145PubMedGoogle Scholar
  87. Schreier AL, Swedell L (2009) The fourth level of social structure in a multi-level society: ecological and social functions of clans in hamadryas baboons. Am J Primatol 71:948–955PubMedGoogle Scholar
  88. Shively CA (2012) Social stress and cardiovascular disease in primates stress and cardiovascular disease. In: Steptoe A, Rosengren A (eds) Hjemdahl P. Springer, London, pp 17–31Google Scholar
  89. Sigg H, Stolba A, Abegglen J, Dasser V (1982) Life history of hamadryas baboons: physical development, infant mortality, reproductive parameters and family relationships. Primates 23:473–487Google Scholar
  90. Smith DG, Kanthaswamy S, Disbrow M, Wagner JL (1999) Reconstruction of parentage in a band of captive hamadryas baboons. Int J Primatol 20:415–429Google Scholar
  91. Sugawara K (1979) Sociological study of a wild group of hybrid baboons between Papio anubis and P. hamadryas; in the Awash Valley, Ethiopia. Primates. 20:21–56Google Scholar
  92. Swedell L, Hailemeskel G, Schreier A (2008) Composition and seasonality of diet in wild hamadryas baboons: preliminary findings from Filoha. Folia Primatol 79:476–490PubMedGoogle Scholar
  93. Swedell L, Saunders J, Schreier A, Davis B, Tesfaye T, Pines M (2011) Female “dispersal” in hamadryas baboons: transfer among social units in a multilevel society. Am J Phys Anthropol 145:360–370PubMedGoogle Scholar
  94. Tamashiro KLK, Nguyen MMN, Sakai RR (2005) Social stress: from rodents to primates. Front Neuroendocrinol 26:27–40PubMedGoogle Scholar
  95. Taylor S (2006) Tend and befriend: biobehavioral bases of affiliation under stress. Curr Dir Psychol Sci 15:273–277Google Scholar
  96. Taylor S, Klien L, Lewis B, Gruenewald T, Gurung R, Updegraff J (2000) Biobehavioural responses to stress in females: tend and befriend, not flight or fight. Psycol Rev 107:411–429Google Scholar
  97. Thorsteinsson E, James J (1999) A meta-analysis of the effects of experimental manipulations of social support during laboratory stress. Psychol Health 14:869–886Google Scholar
  98. Webb E, Thomson S, Nelson A, White C, Koren G, Rieder M (2010) Assessing individual systemic stress through cortisol analysis of archaeological hair. J Arch Sci 37:807–812Google Scholar
  99. Weingrill T, Gray DA, Barret L, Henzi P (2004) Fecal cortisol levels in free-ranging female chacma baboons: relationship to dominance, reproductive state and environmental factors. Horm Behav 4:259–269Google Scholar
  100. Wust S, van Rossum EFC, Federenko IS, Koper JW, Kumsta R, Hellhammer DH (2004) Common polymorphisms in the glucocorticoid receptor gene are associated with adrenocortical responses to psychosocial stress. J Clin Endocrinol Metabol 89:565–573Google Scholar
  101. Yamada J, Stevens B, de Silva N, Gibbins S, Beyene J, Taddio A, Newman C, Koren G (2007) Hair cortisol as a potential biologic marker of chronic stress in hospitalized neonates. Neonatology 92:42–49PubMedGoogle Scholar
  102. Yamane A, Shotake T, Mori A, Boug A, Iwamoto T (2003) Extraunit paternity of hamadryas baboons (Papio hamadryas) in Saudi Arabia. Ethol Ecol Evol 15:379–387Google Scholar
  103. Zinner D, Krebs E, Schrod A, Kaumanns W (2006) Early sexual maturity in male hamadryas baboons (Papio hamadryas hamadryas) and its reproductive implications. Am J Phys Anthropol 129:584–589PubMedGoogle Scholar

Copyright information

© Japan Monkey Centre and Springer Japan (outside the USA) 2015

Authors and Affiliations

  • Nicolaas H. Fourie
    • 1
    Email author
  • Clifford J. Jolly
    • 2
  • Jane E. Phillips-Conroy
    • 3
    • 4
  • Janine L. Brown
    • 5
  • Robin M. Bernstein
    • 6
  1. 1.Biobehavioral Branch, Intramural Research Program, National Institute of Nursing ResearchNational Institutes of HealthBethesdaUSA
  2. 2.Department of AnthropologyNew York UniversityNew YorkUSA
  3. 3.Department of Anatomy and NeurobiologyWashington University School of MedicineSaint LouisUSA
  4. 4.Department of AnthropologyWashington UniversitySt. LouisUSA
  5. 5.Smithsonian Conservation Biology InstituteCenter for Species SurvivalFront RoyalUSA
  6. 6.Department of AnthropologyUniversity of Colorado BoulderBoulderUSA

Personalised recommendations