Letter | Published:

Climate and reproduction of grizzly bears in Yellowstone National Park

Nature volume 274, pages 888889 (31 August 1978) | Download Citation

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Abstract

CONTROVERSY surrounds the conflicts between the requirements of human safety and the preservation of grizzly bears (Ursus arctos horribilis) in western North America. It has been difficult to separate the effect of factors such as the closure of garbage dumps from that of the climate. It has also proved difficult to relate climatic data to changes in the populations of large mammals. I report here a correlation of climatic change with fluctuations in the sizes of litters of grizzly bears born in Yellowstone National Park, Wyoming, during 1958–1976. The decrease in litter sizes observed since the closure of garbage dumps seems to be largely a consequence of unfavourable weather during the periods of the final fattening of the mother, winter sleep, birth, lactation and early spring foraging. This study represents one of the few times that the effects of climate have been demonstrated for large omnivorous or carnivorous mammals.

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References

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    Symposium on Changes of Climate, Arid Zone Res. 20, 125–150 (UNESCO, Paris, 1963).

  2. 2.

    Climatological Data for Wyoming (U. S. Department of Commerce, Washington, DC) (1958–76).

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    , & School of Forestry, Bulletin 40 (Univ. Montana, Missoula, Montana 1974).

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    , , , , & Misc. Rept 10 (National Park Service, Washington, DC, 1977).

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    & Wildl. Monogr. 32 (The Wildl. Soc., Washington, DC, 1972).

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    Trans. North Am. Wildl. Nat. Res. Conf. 41, 431–438 (1976).

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    Proc. Int. Bear Res. 4 (National Park Service, Glacier National Park, Montana, in the press).

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    Can. Wildl. Service Rep 34, 86pp (1972).

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    J. Wildl. Manag. 36, 556–561 (1972).

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    The Northern Yellowstone Elk, National Park Service, Yellowstone National Park (Wyoming 1974).

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    Defenders of Wildlife News October, 577–568 (1973).

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Author information

Affiliations

  1. Department of Biology, Montana State University, Bozeman, Montana 59717

    • HAROLD D. PICTON

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DOI

https://doi.org/10.1038/274888a0

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