Behavioral Ecology and Sociobiology

, Volume 54, Issue 4, pp 352–358

Factors influencing length of maternal care in brown bears (Ursus arctos) and its effect on offspring

Original Article

Abstract

Length of maternal care, i.e. the interval between successfully raised litters, is the most important factor explaining the variation in reproductive rate among brown-bear (Ursus arctos) populations. In this paper, we examine the variation in length of maternal care in radio-marked brown bears and its effect on their offspring in northern Sweden. Young stayed with their mothers for 1.4–1.5 or 2.4–2.5 (in one case 3.5) years and were weaned with body masses varying from 17 to 69 kg. The probability of yearling litters staying with their mother for a 2nd year increased with decreasing yearling body mass, and was higher for litters with two offspring than for litters with one or three to four offspring. Staying with their mothers for a 2nd year had a positive effect on mass gain in yearlings and this effect was more pronounced in litters with two than three to four offspring. Body mass of 2-year-olds was not related to age of weaning, suggesting that keeping offspring for an additional year mainly compensated for low yearling body mass. If large offspring body mass positively affects later offspring survival and reproduction, mothers may be able to optimize the length of maternal care according to the litter size and the size of their yearlings.

Keywords

Litter interval Maternal care Litter size Body mass Ursus arctos 

References

  1. Arnemo JM, Linnell JDC, Wedul SJ, Ranheim B, Odden J, Andersen R (1999) Use of intraperitoneal radio-transmitters in lynx Lynx lynx kittens: anaesthesia, surgery and behaviour. Wildl Biol 5:245–250Google Scholar
  2. Arnold JPY, Ramsay MA (1994) Milk production and milk consumption in polar bears during the ice-free period in western Hudson Bay. Can J Zool 72:1365–1370Google Scholar
  3. Arnold W (1990) The evolution of marmot sociality. II. Costs and benefits of joint hibernation. Behav Ecol Sociobiol 27:239–246Google Scholar
  4. Cattet MRL, Caulkett NA, Obbard ME, Stenhouse GB (2002) A body-condition index for ursids. Can J Zool 80:1156–1161CrossRefGoogle Scholar
  5. Charnov EL (1982) The theory of sex allocation. Princeton University Press, PrincetonGoogle Scholar
  6. Cheney DL, Seyfarth RM, Andelman SJ, Lee PC (1988) Reproductive success in vervet monkeys. In: Clutton-Brock TH (ed) Reproductive success: studies of individual variation in contrasting breeding systems. University of Chicago Press, Chicago, pp 384–402Google Scholar
  7. Clutton-Brock TH (1991) The evolution of parental care. Princeton University Press, PrincetonGoogle Scholar
  8. Clutton-Brock TH, Guinness FE, Albon SD (1982) Red deer: behavior and ecology of two sexes. University of Chicago Press, ChicagoGoogle Scholar
  9. Clutton-Brock TH, Albon SD, Guinness FE (1986) Great expectations: dominance, breeding success and offspring sex ratios in red deer. Anim Behav 34:460–471Google Scholar
  10. Congdon JD, Sels RVC (1993) Relationships of reproductive trait and body-size with attainment of sexual maturity and age in blandings turtles (Emyoidea blandingi). J Evol Biol 6:547–557Google Scholar
  11. Craighead JJ, Sumner JS, Mitchell JA (1995) The grizzly bears of Yellowstone: their ecology in the Yellowstone ecosystem 1959–1992. Island, Washington DCGoogle Scholar
  12. Dahle B, Swenson JE (2003) Family break-up in brown bears: are young forced to leave? J Mammal 84Google Scholar
  13. Derocher AE, Stirling I (1995) Temporal variation in reproduction and body mass of polar bears in western Hudson Bay. Can J Zool 73:1657–1665Google Scholar
  14. Fairbanks LA, McGurie MT (1995) Maternal condition and the quality of maternal care in vervet monkeys. Behaviour 132:733–754Google Scholar
  15. Festa-Bianchet M, Jorgenson JT, Wishart WD (1994) Early weaning in bighorn sheep, Ovis canadensis, affects growth of males but not females. Behav Ecol 5:21–27Google Scholar
  16. Festa-Bianchet M, Jorgenson JT, Reale D (2000) Early development, adult mass and reproductive success in bighorn sheep. Behav Ecol 11:633–639Google Scholar
  17. Frković A, Huber D, Kusak J (2001) Brown bear litter sizes in Croatia. Ursus 12:103–106Google Scholar
  18. Green WCH, Rothstein A (1991a) Sex bias or equal opportunity? Patterns of maternal investment in bison. Behav Ecol Sociobiol 29:373–384Google Scholar
  19. Green WCH, Rothstein A (1991b) Trade offs between growth and reproduction in female bison. Oecologia 86:521–527Google Scholar
  20. Hall AJ, McConnell BJ, Barker RJ (2001) Factors affecting first-year survival in grey seals and their implications for life history strategy. J Anim Ecol 70:138–149CrossRefGoogle Scholar
  21. Hewison AJM, Gaillard JM (1999) Successful sons or advantaged daughters? The Trivers-Willard model and sex-biased maternal investment in ungulates. Trends Ecol Evol 14:229–234PubMedGoogle Scholar
  22. Hilderbrand GV, Schwartz CC, Robbins CT, Hanley TA (2000) Effects of hibernation and reproductive status on body mass and condition of coastal brown bears. J Wildl Manage 64:178–183Google Scholar
  23. Jarman P (1983) Mating system and sexual size dimorphism in large terrestrial mammalian herbivores. Biol Rev 58:485–520Google Scholar
  24. Koskela E (1998) Offspring growth, survival and reproductive success in the bank vole: a litter size manipulation experiment. Oecologia 115:379–384CrossRefGoogle Scholar
  25. Lee PC, Moss CJ (1986) Early maternal investment in male and female African elephant calves. Behav Ecol Sociobiol 18:353–361Google Scholar
  26. Lee PC, Majluf P, Gordon IJ (1991) Growth, weaning and maternal investment from a comparative perspective. J Zool 225:99–114Google Scholar
  27. Lloyd DG (1987) Selection of offspring size at independence and other size versus number strategies. Am Nat 129:800–817CrossRefGoogle Scholar
  28. Maynard Smith J (1980) A new theory of sexual investment. Behav Ecol Sociobiol 7:247–251Google Scholar
  29. Maynard Smith J (1982) Evolution and the theory of games. Cambridge University Press, CambridgeGoogle Scholar
  30. Maynard Smith J, Parker G (1976) The logic of asymmetric contests. Anim Behav 24:159–175Google Scholar
  31. McCullagh P, Nelder JA (1989) Generalized linear models. Chapman and Hall, LondonGoogle Scholar
  32. McLellan B (1994) Density dependent population regulation in brown bears. In: Taylor M (ed) Density dependent population regulation in black, brown and polar bears. Monograph series no. 3. International Association for Bear Research and Management, Port City, Washington DC, pp 15–25Google Scholar
  33. McMahon CR, Burton HR, Bester MN (2000) Weaning mass and the future survival of juvenile southern elephant seals, Mirounga leeonina at Macquarie Island. Antarct Sci 12:149–153Google Scholar
  34. Mendl M (1988) The effects of litter size on mother offspring relationships and behavioural and physical development in several mammalian species (principally rodents). J Zool 215:15–34Google Scholar
  35. Ono KA, Boness DJ (1996) Sexual dimorphism in sea lion pups: differential maternal investment, or sex specific differences in energy allocation. Behav Ecol Sociobiol 38:31–41CrossRefGoogle Scholar
  36. Ramsay MA, Stirling I (1988) Reproductive biology and ecology of female polar bears (Ursus maritimus). J Zool 214:601–634Google Scholar
  37. Roff DA (1992) The evolution of life histories; theories and analysis. Chapman and Hall, New YorkGoogle Scholar
  38. Samson C, Huot J (1995) Reproductive biology of female black bears in relation to body mass in early winter. J Mammal 76:68–77Google Scholar
  39. Stearns SC (1992) The evolution of life histories. Oxford University Press, New YorkGoogle Scholar
  40. Swenson JE, Sandegren F (1999) Conservation of European brown bear populations: experinces from Scandinavia. In: Layna JF, Heredia B, Palomero G, Doadr I (eds) La conservación del oso pardo en Europa: un reto de cara al siglo XXI. (io), MadridGoogle Scholar
  41. Swenson JE, Sandegren F, Bjärvall A, Söderberg A, Wabakken P, Franzén R (1994) Size, trend, distribution and conservation of the brown bear Ursus arctos population in Sweden. Biol Conserv 70:9–17Google Scholar
  42. Swenson JE, Sandegren F, Segerström P, Brunberg S (2001a) Factors associated with loss of brown bear cubs in Sweden. Ursus 12:69–80Google Scholar
  43. Swenson JE, Dahle B, Sandegren F (2001b) Intraspecific predation in Scandinavian brown bears older than cubs-of-the-year. Ursus 12:81–92Google Scholar
  44. Tait DE (1980) Abandonment as a reproductive tactic—the example with grizzly bears. Am Nat 115:800–808CrossRefGoogle Scholar
  45. Trillmich F (1986) Maternal investment and sex allocation in the Galapagos fur seal, Arctocepahalus galapagoensis. Behav Ecol Sociobiol 19:157–164Google Scholar
  46. Trivers RL (1974) Parent-offspring conflict. Am Zool 14:249–264Google Scholar
  47. Tummaruk P, Lundeheim N, Einarsson S, Dalin AM (2001) Effect of birth litter size, birth parity number, growth rate, backfat thickness and age at first mating of gilts on their reproductive performance as sows. Anim Reprod Sci 66:225–237CrossRefPubMedGoogle Scholar
  48. Williams GC (1966) Natural selection, the cost of reproduction and a refinement of Lack's principle. Am Nat 100:687–690CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  1. 1.Department of Biology and Nature ConservationAgricultural University of NorwayÅsNorway

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