. The Canadian field-naturalist. 292 The Canadian Field-Naturalist Vol. 92 Twinning in Dall Sheep Manfred Hoefs Yukon Game Branch, Whitehorse, Yukon Territory YIA 2C6 Hoefs, M. 1978. Twinning in Dall Sheep. Canadian Field-Naturalist 92(3): 292-293. During an Elk investigation carried out by the Yukon Game Branch an observation was made of a Dall Sheep (Ovis dalli dalli) ewe with two lambs. This appears to be a true instance of twinning. The observation was made on 20 May 1977, on a mountain along the Nordenskjold River, some 100 km NW of Whitehorse, Yukon Territory. The Yukon Game Branch maint
. The Canadian field-naturalist. 292 The Canadian Field-Naturalist Vol. 92 Twinning in Dall Sheep Manfred Hoefs Yukon Game Branch, Whitehorse, Yukon Territory YIA 2C6 Hoefs, M. 1978. Twinning in Dall Sheep. Canadian Field-Naturalist 92(3): 292-293. During an Elk investigation carried out by the Yukon Game Branch an observation was made of a Dall Sheep (Ovis dalli dalli) ewe with two lambs. This appears to be a true instance of twinning. The observation was made on 20 May 1977, on a mountain along the Nordenskjold River, some 100 km NW of Whitehorse, Yukon Territory. The Yukon Game Branch maintained a field camp in the area from 20 May to 13 June 1977, during which time these sheep were kept under observation. The following circumstances lead me to assume that this is a true instance of twinning in Dall Sheep. The ewe and the two lambs were observed on 20 May, which is the peak lambing period in the southern Yukon (Hoefs 1975), in isolation from other sheep. No other nursery sheep were observed during our survey, and the nearest rams were 1 km away. Ewes are known to separate from nursery bands a few days prior to giving birth and to rejoin the bands when their new-born lambs are 2-3 days old. Both lambs still had the "dirty-gray" color characteristic of Dall Sheep lambs during the first few days of life (Figure 1). Both lambs were observed to nurse, which had never been documented in "baby-sitting" situations: a ewe only allows her own lamb to suckle. Both lambs were observed to stay with the ewe after the group had joined a nursery band. There is so far no conclusive evidence of twinning in Dall Sheep. Although a few investigators state that twinning may occasionally occur (Dixon 1938: Murie 1944: Palmer 1941, USA Fish and Wildlife Service unpublished report), detailed population studies have not documented it (Alaska Department of Fish and Game unpublished reports by F. Jones 1963, M. Pitzman 1969. L. Nichols and W. Heimer 1972; Luckhurst
Size: 1366px × 1828px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorottawafieldnaturalistsclub, bookcentury1900, bookcolle
