Breeding Season of Wolves, Canis lupus, in Relation to Latitude
L. David Mech
Abstract: A significant relationship was found between Wolf (Canis lupus) breeding dates and latitudes between 12° and 80° N, with Wolves breeding earlier at lower latitudes, probably because of differences in seasonality.
Key Words: Wolf, Canis lupus, reproduction, latitude, breeding, mating.
Mech, L. David. 2002. Breeding season of Wolves, Canis lupus, in relation to latitude. Canadian Field Naturalist 116(1):139-140.
This resource should be cited as:Mech, L. David. 2002. Breeding season of Wolves, Canis lupus, in relation to latitude. Canadian Field Naturalist 116(1):139-140. Jamestown, ND: Northern Prairie Wildlife Research Center Online. http://www.npwrc.usgs.gov/resource/mammals/latitude/index.htm (Version 12AUG2004).
A general relationship between breeding dates in Wolves (Canis lupus) and latitudes from 41°-71° N was noticed by Mech (1970:117) when he summarized published data from several locales. However, he conducted no statistical test of this hypothesis. Herein, I add data from other areas of latitude from 12° to 80° N (Table 1) and statistically test the effect of latitude.
I used latitude as the independent variable in a simple linear regression and the reported breeding date as the dependent variable. For breeding date, I used the mid date for the reported breeding season and converted all dates to sequential numbers starting with 15 October to facilitate comparing breeding dates before and after the start of the calendar year.
The relationship between breeding date and latitude was highly significant (r² = 0.74; P < 0.0001; y = 16.19 + 2.23x), supporting Mech's (1970) hypothesis. On average, breeding season shifts 22 days later with each 10° latitude increase. It seems reasonable to suggest that the shift is related to differences in general seasonality and thus in associated ecological conditions.
| Location | N Latitude | Season | Authority |
| S. India | 12° | October | Kumar and Rahmani 2002 |
| Arizonaa | 34° | February, March | W. Brown, personal communication |
| Illinoisa | 42° | February | Rabb 1968 |
| Yellowstone National Parkb | 45° | February | Smith et al. |
| Ontario | 47° | Early March | Joslin 1966 |
| North Dakota | 46°-49° | January | Bailey 1926 |
| Isle Royale (Michigan) | 47° | Late February | Mech 1966 |
| Minnesota | 48° | February | Mech and Knick 1978; Fritts and Mech 1981; Fuller 1989 |
| British Columbia | 51°- 53° | March | Cowan 1947 |
| Germanya | 52° | Mid March | Schonberner 1965 |
| Alberta | 60° | February, March | Soper 1942; Fuller and Novakowski |
| Northwest Territories | 60°-65° | Late March | Kelsall 1960 |
| Alaska | 60°-71° | March | Murie 1944; Kelly 1954; Rausch 1967; Lentfer and Sanders 1973; Mech et al. 1998 |
| Finland | 60°-70° | March | Pulliainen 1965 |
| Russia | 71° | Late March-early April | Makridin 1962 |
| Ellesmere Island | 80° | Late March-early April | Mech 1993 |
| a Captive wolves b Wolves translocated from 53°-56° N. |
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Acknowledgments
This study was supported by the Biological Resources Division of U.S. Geological Survey and the U.S. Department of Agriculture, North Central Research Station.
Literature Cited
Bailey, V. 1926. A biological survey of North Dakota. U.S. Department of Agriculture, Biological Survey, North American Fauna 49.
Cowan, I. M. 1947. The timber wolf in the Rocky Mountain national parks of Canada. Canadian Journal Research 25: 139-174.
Fritts, S. H., and L. D. Mech. 1981. Dynamics, movements, and feeding ecology of a newly protected wolf population in northwestern Minnesota. Wildlife Monograph 80.
Fuller, T. K. 1989. Population dynamics of wolves in north-central Minnesota. Wildlife Monograph 105.
Fuller, W. A., and N. S. Novakowski. 1955. Wolf control operations, Wood Buffalo National Park, 1951-1952. Canadian Wildlife Service, Wildlife Management Bulletin Series 1, No. 11.
Joslin, P. W. B. 1966. Summer activities of two timber wolf (Canis lupus) packs in Algonquin Park. M.S. thesis, Univ. of Toronto, 99pp.
Kelly, M. W. 1954. Observations afield on Alaskan wolves. Proceedings of Alaska Science Conference 5:35.
Kelsall, J. P. 1960. Co-operative studies on barren ground caribou 1957-58. Canadian Wildlife Service, Wildlife Management Bulletin Series 1, No. 12.
Kumar, S. and A. R. Rahmani. 2002. Ecology of Indian Wolf, (Canis lupus pallipes, in the Great Indian Bustard Sanctuary, Nannaj, Solapur, Maharashtra, India. Biological Conservation. in press.
Lentfer, J. W., and D. K. Sanders. 1973. Notes on the captive wolf (Canis lupus) colony, Barrow, Alaska. Canadian Journal of Zoology 51: 623-627.
Makridin, V. P. 1962. The wolf in the Yamal north. Zoological Zhurnal 41:1413-1417.
Mech, L. D. 1966. The wolves of Isle Royale. U. S. National Park Service Fauna Series No. 7.
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Murie, A. 1944. The wolves of Mount McKinley. U.S. National Park Service Fauna Series No. 5.
Pulliainen, E. 1965. Studies of the wolf (Canis lupus L.) in Finland. Annales Zoologici Fennici 2:215-259.
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Rausch, R. A. 1967. Some aspects of the population ecology of wolves, Alaska. American Zoologist 7:253-265.
Schonberner, D. 1965. Observations on the reproductive biology of the wolf. Zeitschrift fur Sauzetierkunde 30:171-178.
Smith, D. W., K. M. Murphy, and D. S. Guernsey. 1998. Yellowstone Wolf Project. Annual Report YCR-NR-99-1. Yellowstone Center for Resources, Yellowstone National Park, Wyoming.
Soper, J. D. 1942. Mammals of Wood Buffalo Park, northern Alberta and District of Mackenzie. Journal of Mammalogy 23:119-145.
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