Behavioral Ecology and Sociobiology

, Volume 24, Issue 6, pp 377–385 | Cite as

Pre-natal investment in reproduction by female Antarctic fur seals

  • I. L. Boyd
  • T. S. McCann


Maternal investment, in terms of pup birth mass, in gestation by Antarctic fur seals (Arctocephalus gazella) was related to the date of birth in two consecutive years. There were significant differences in birth mass between years and between the sexes within years. Birth mass was used to calculate the mean energetic cost of producing a pup to parturition. The cost for a male pup in 1986 was 173 MJ while it was 191 MJ in 1987. For female pups the cost was 152 and 166 MJ in 1986 and 1987 respectively. Given the probable pattern of foetal growth, this constitutes a minimum of 5–15% of the maternal energy budget in the final months of gestation. Birth mass varied inversely with date of birth, but more strongly for male than for female pups. The sex ratio at birth was unity in both years and this did not vary with time through the birth season. In a subsample of mothers (n=79) which were captured on the day of birth, there was a decline in the body mass and standard length with date of birth. Male birth mass was directly related to maternal mass and maternal condition (mass/length) but there was no significant relationship for females. These results suggest that the growth of male foetuses is limited by maternal resources while female foetuses do not exploit fully maternal resources.


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  1. American Society of Mammalogist (1967) Standard measurements of seals. J Mamm 48:459–462Google Scholar
  2. Anderson SS, Fedak M (1987) Grey seal, Halichoerus grypus, energetics: females invest more in male offspring. J Zool (London) 211:667–679Google Scholar
  3. Battaglia FC, Meschia G (1986) An introduction to fetal physiology. Academic Press, LondonGoogle Scholar
  4. Blueweiss L, Fox H, Kudzma V, Nakashima D, Peters R, Sams S (1978) Relationship between body size and some life history parameters. Oecologia 37:257–272Google Scholar
  5. Boyd IL (1982) Reproduction of grey seals with reference to factors influencing fertility. PhD thesis, Cambridge UniversityGoogle Scholar
  6. Boyd IL (1984) The relationship between body condition and the timing of implantation in pregnant grey seals (Halichoerus grypus). J Zool (London) 203:113–123Google Scholar
  7. Brody S (1945) Bioenergetics and growth. Hafner Press, New YorkGoogle Scholar
  8. Charnov EL, Schaffer WM (1973) Life-history consequences of natural selection: Cole's result revisited. Am Nat 107:791–793Google Scholar
  9. Close WH, Noblet J, Heavens RP (1985) Studies of the energy metabolism of the pregnant sow. 2. The partition and utilization of metabolizable energy intake in pregnant and non-pregnant animals. Br J Nutr 53:251–265Google Scholar
  10. Clutton-Brock TH, Guinness F, Albon S (1982) Red deer. Behaviour and ecology of two sexes. Edinburgh University Press, EdinburghGoogle Scholar
  11. Costa DP, Croxall JP, Duck C (1989) Foraging energetics of Antarctic fur seals, Arctocephalus gazella, in response to seasonal changes in prey availability and pup sex. Ecology (in press)Google Scholar
  12. Costa DP, Trillmich F, Croxall JP (1989) Intraspecific allometry of neonatal size in the Antarctic fur seal (Arctocephalus galapagoensis). Behav Ecol Sociobiol 22:361–364Google Scholar
  13. Doidge DW, Croxall JP, Baker JR (1984) Density-dependent pup mortality in the Antarctic fur seal Arctocephalus gazella at South Georgia. J Zool (London) 202:449–460Google Scholar
  14. Doidge DW, Croxall JP, Ricketts C (1984) Growth rates of Antarctic fur seal Arctocephalus gazella pups at South Georgia. J Zool (London) 202:449–460Google Scholar
  15. Fisher RA (1930) The genetical theory of natural selection. Oxford University Press, OxfordGoogle Scholar
  16. Frazer JFD, Hugget AStG (1974) Species variations in the foetal growth rates of eutherian mammals. J Zool (London) 174:481–509Google Scholar
  17. Gentry RL, Holt JR (1982) Equipment and techniques for handling northern fur seals. US Dep Commer, NOAA Tech Rep NMFS SSRF 758, pp 15Google Scholar
  18. Kovacs KM, Lavigne DM (1986) Maternal investment and neonatal growth in Phocid seals. J Anim Ecol 55:1035–1051Google Scholar
  19. Lavigne DM, Stewart REA (1979) Energy content of harp seal placentas. J Mammal 60:854–855Google Scholar
  20. McCann TS (1980) Territoriality and breeding behaviour of adult male Antarctic fur seals. J Zool (London) 192:295–310Google Scholar
  21. McCann TS, Fedak M, Harwood J (1989) Parental investment in southern elephant seals, Mirounga leonina. Behav Ecol Sociobiol (in press)Google Scholar
  22. McClure PA (1981) Sex biased litter reduction in food restricted wood rats (Neotoma floridana). Science 211:1058–1060Google Scholar
  23. Maynard-Smith J (1980) A new theory of sexual investment. Behav Ecol Sociobiol 7:247–251Google Scholar
  24. Millar JS (1981) Pre-partum reproductive characteristics of eutherian mammals. Evolution 35:1149–1163Google Scholar
  25. Payne MR (1977) Growth of a fur seal population. Phil Trans R Soc London, Ser B 279:67–79Google Scholar
  26. Payne MR (1979) Growth in the Antarctic fur seal Arctocephalus gazella. J Zool (London) 187:1–20Google Scholar
  27. Rahn H (1982) Comparison of embryonic development in birds and mammals; birth weight, time and cost. In: Taylor CR, Johansen K, Bolis L (eds) A companion to animal physiology. Cambridge University Press, Cambridge, pp 124–137Google Scholar
  28. Spotte S (1982) The incidence of twins in pinnipeds. Can J Zool 60:2226–2233Google Scholar
  29. Stirling I, McEwan EH (1975) The caloric value of whole ringed seals (Phoca hispida) in relation to polar bear (Ursus maritimus) ecology and hunting behaviour. Can J Zool 53:1021–1027Google Scholar
  30. Trivers RL, Willard DE (1973) Natural selection of parental ability to vary the sex ratio of offspring. Science 179:90–92Google Scholar
  31. Worthy GAJ, Lavigne DM (1983) Changes in energy stores during postnatal development of the harp seal, Phoca groenlandica. J Mamm 64:89–96Google Scholar

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • I. L. Boyd
    • 1
  • T. S. McCann
    • 1
  1. 1.British Antarctic SurveyNatural Environment Research CouncilCambridgeGreat Britain

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