Surplus killing as exemplified by wolf predation on newborn caribou

1985 ◽  
Vol 63 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Frank L. Miller ◽  
Anne Gunn ◽  
Eric Broughton
Keyword(s):  
Northwest Territories ◽  
Canis Lupus ◽  
Rangifer Tarandus ◽  
The Other ◽  
Wolf Predation ◽  
Barren Ground ◽  
Rangifer Tarandus Groenlandicus

We searched for newborn calf carcasses of migratory barren-ground caribou (Rangifer tarandus groenlandicus) in June 1982 in the Northwest Territories. On 17 June, we found 34 calves killed by wolves (Canis lupus), clumped in a 3-km2 area. The calves had been killed apparently within minutes of each other and about 24 h before being found. Wolves had not fed on 17 of the carcasses and had only partially eaten the other 17. Ground observations illustrate the speed of and efficiency with which wolves can kill calves: a single wolf killed three calves on one occasion and three and possibly four calves on a second occasion at average kill rates of 1 calf/min, and 1 calf/8 min or 1 calf/6 min between the first and last deaths. We attributed the surplus killing of newborn caribou calves to their high densities and their vulnerability on the calving grounds. We recommend that a distinction be made between "surplus killing" and "excessive killing" by predators.

scholarly journals Predation of a Barren-ground Caribou, Rangifer tarandus groenlandicus, by a Single Gray Wolf, Canis lupus, in Northern Manitoba, Canada

2010 ◽  
Vol 124 (3) ◽  
pp. 270
Author(s):  
Brian W. Kiss ◽  
Scott K. Johnstone ◽  
Robert P. Berger
Keyword(s):  
Canis Lupus ◽  
Rangifer Tarandus ◽  
Open Water ◽  
Gray Wolf ◽  
Small Section ◽  
Barren Ground ◽  
Rangifer Tarandus Groenlandicus

A single Gray Wolf (Canis lupus) was observed successfully trapping and predating a Barren-ground Caribou (Rangifer tarandus groenlandicus) in a small section of open water.

scholarly journals Asymmetry in antlers of barren-ground caribou, Northwest Territories, Canada

Rangifer ◽  
1986 ◽  
Vol 6 (2) ◽  
pp. 195
Author(s):  
Frank L. Miller
Keyword(s):  
Northwest Territories ◽  
Rangifer Tarandus ◽  
Barren Ground ◽  
Age Class ◽  
The Right ◽  
Rangifer Tarandus Groenlandicus

Pairs of antlers were obtained from 287 barren-ground caribou (Rangifer tarandus groenlandicus) of the Kaminuriak herd in the Northwest Territories, Canada. The morphological dominance of the brow tines by antler pair was determined: 15.7% were enlarged on the left; 14.6% on the right; 14.6% on both sides; and 55.1% on neither side. No evidence for a greater rate of occurrence of left or right dominance of the brow tine was obtained when considered by sex or age class (P >0.05). Antler pairs with both brow and bez tines present varied from 84.4% for males with their 5th to 10th set of antlers; 39.3% for males with their 2nd to 4th set; 21.2% for females with their 5th to 16th set; and 6.3% for females with their 1st to 4th set. Both brow and bez tines were present proportionately more often than expected on antler pairs from males compared to females regardless of age (P <0.005). Both brow and bez tines also were present proportionately more often than expected on antler pairs from males (P <0.005), females (P <0.01), or both sexes combined (P <0.01) with their 5th or later set than compared to when they had their 4th or earlier set.

Wolf predation in a multiple-ungulate system in northern British Columbia

1998 ◽  
Vol 76 (8) ◽  
pp. 1551-1569 ◽  
Author(s):  
A T Bergerud ◽  
J P Elliott
Keyword(s):  
British Columbia ◽  
Canis Lupus ◽  
Birth Rate ◽  
Rangifer Tarandus ◽  
Adult Mortality ◽  
Recruitment Rate ◽  
Wolf Predation ◽  
Rate Of Increase ◽  
Ovis Dalli ◽  
Hunting Statistics

Caribou (Rangifer tarandus), elk (Cervus canadensis), moose (Alces alces), and Stone's sheep (Ovis dalli stonei) were either decreasing or stable in numbers in two areas in northeastern British Columbia in 1981-1982, prior to reductions in wolf (Canis lupus) numbers. Following the reduction of wolf numbers, recruitment improved 2-5 times for all four species, and all populations increased, based on either hunting statistics, census results, and (or) recruitments greater than 24 offspring at 9 months of age per 100 females. Recruitment of offspring at 9 months of age, when regressed against wolf numbers, declined with decelerating slopes for all four species. This inverse functional response is hypothesized to result from the preparturient spacing of females to reduce predation risk, and in this regard moose seem the least secure and sheep the most effectively spaced. For the four species, mean recruitment at 9 months of age that balanced adult mortality and provided a finite rate of increase of 1.00 was 24.16 ± 0.91 offspring/100 females (n = 11, coefficient of variation = 12.5%). The predicted recruitment rate for all four species in the absence of wolves was 53-57 offspring/100 females. But the birth rate of moose was much higher than those of the other species, indicating greater loss to other factors of which bear predation may be the greatest. Following wolf reductions of 60-86% of entire travelling packs, the wolves quickly recolonized the removal zones, with rates of increase ranging from 1.5 to 5.6.

Kill rate by wolves on moose in the Yukon

2000 ◽  
Vol 78 (1) ◽  
pp. 49-59 ◽  
Author(s):  
R D Hayes ◽  
A M Baer ◽  
U Wotschikowsky ◽  
A S Harestad
Keyword(s):  
Canis Lupus ◽  
Snow Depth ◽  
Prey Density ◽  
Large Scale ◽  
Rangifer Tarandus ◽  
Prey Selection ◽  
Ecological Factors ◽  
Predation Rate ◽  
Wolf Predation ◽  
Kill Rate

We studied the kill rate by wolves (Canis lupus) after a large-scale wolf removal when populations of wolves, moose (Alces alces), and woodland caribou (Rangifer tarandus caribou) were all increasing. We followed a total of 21 wolf packs for 4 winters, measuring prey selection, kill rates, and ecological factors that could influence killing behavior. Wolf predation was found to be mainly additive on both moose and caribou populations. Kill rates by individual wolves were inversely related to pack size and unrelated to prey density or snow depth. Scavenging by ravens decreased the amount of prey biomass available for wolves to consume, especially for wolves in smaller packs. The kill rate by wolves on moose calves was not related to the number of calves available each winter. Wolves did not show a strong switching response away from moose as the ratio of caribou to moose increased in winter. The predation rate by wolves on moose was best modeled by the number and size of packs wolves were organized into each winter.

scholarly journals Age-specific fecundity of the Beverly herd of barren-ground caribou

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 257 ◽  
Author(s):  
Donald C. Thomas ◽  
Samuel J. Barry
Keyword(s):  
Rangifer Tarandus ◽  
Barren Ground ◽  
Rangifer Tarandus Groenlandicus

The age-specific fecundity of the Beverly herd of barren-ground caribou (Rangifer tarandus groenlandicus) was monitored each winter from 1979-80 through 1986-87. Fecundity in 840 females increased with age from 12% in yearlings to 86% at age 5 years and it did not decline in old (> 11 yr) females. Significant variations occurred among winters and even between two subherds in one winter. Reproductive abnormalities were detected in 2 of 840 females and a probable resorption in 1 of 420 females collected in March. Only about 5% of the fetuses were conceived late, possibly by repeat ovulators. Combining survival and fecundity data yielded age-specific calf production, which indicated that, for example, 54% of calves were born to females 3-6 years old.

Morphology of the barren-ground caribou ovary

1978 ◽  
Vol 56 (8) ◽  
pp. 1684-1696 ◽  
Author(s):  
T. Charles Dauphiné Jr.
Keyword(s):  
Connective Tissue ◽  
Rangifer Tarandus ◽  
Corpora Lutea ◽  
Seasonal Incidence ◽  
Histological Techniques ◽  
Northern Canada ◽  
Ovary Weight ◽  
Barren Ground ◽  
Ovarian Stroma ◽  
Rangifer Tarandus Groenlandicus

Reproductive tracts were collected from 532 female caribou (Rangifer tarandus groenlandicus) in northern Canada over a [Formula: see text]-year period. Ovaries were weighed and scrutinized by gross and histological techniques. Ovaries of nulliparous and nongravid, parous cows responded to follicular fluctuations by increasing in weight in summer and declining in winter. Weights of ovaries from calves, yearlings, and 2 year olds overlapped extensively. Formation of corpora lutea of pregnancy more than doubled ovary weight. During gestation ovary weight declined and then partially recovered; it increased with age in pregnant cows. The number and size of follicles [Formula: see text] diameter increased with age until puberty, reaching greatest development just before the autumn rut. After puberty the seasonal incidence of such follicles remained stable except during gestation, when it declined. Corpora lutea of pregnancy regressed to form apparently permanent scars composed of vascular and connective tissue remnants. Secondary corpora lutea developed in 35% of the cows at or before conception and upon regression produced scars which were not permanent. Regressing corpora lutea of estrus also disappeared into the ovarian stroma, apparently within 1 year. In individual cows one ovary, selected at random, dominated in the production of ova and corpora lutea.

scholarly journals Pack Size of Wolves, Canis lupus, on Caribou, Rangifer tarandus, Winter Ranges in Westcentral Alberta

2006 ◽  
Vol 120 (3) ◽  
pp. 313 ◽  
Author(s):  
Gerald W. Kuzyk ◽  
Jeff Kneteman ◽  
Fiona K. A. Schmiegelow
Keyword(s):  
Canis Lupus ◽  
Landscape Change ◽  
Rangifer Tarandus ◽  
Prey Size ◽  
Rocky Mountain ◽  
Predation Pressure ◽  
Resource Extraction ◽  
Rangifer Tarandus Caribou ◽  
Pack Size ◽  
Wolf Predation

We studied pack size of Wolves (Canis lupus) on Woodland Caribou (Rangifer tarandus caribou) winter ranges in westcentral Alberta. These Caribou winter ranges are experiencing increasing pressure from resource extraction industries (forestry, energy sector) and concerns have been raised regarding increased Wolf predation pressure on Caribou in conjunction with landscape change. Thirty-one Wolves, from eight Wolf packs, were fitted with radiocollars on two Caribou winter ranges in the Rocky Mountain foothills, near Grande Cache, Alberta (2000-2001). There was a mean of 8.2 Wolves/pack and between 30 and 39 Wolves on each of the RedRock/Prairie Creek and Little Smoky Caribou ranges. The average pack size of Wolves in this region does not appear to have increased over that recorded historically, but the range (5-18) in the number of Wolves per pack varied considerably over our study area. Wolves preyed predominately on Moose (Alces alces), averaging one Moose kill every three to five days. There was some indication that pack size was related to prey size, with the smallest pack preying on Deer (Odocoileus spp.). It was clear that Caribou could not be the primary prey for Wolves, due to their low numbers, and relative to the pack size and Wolf kills we observed.

Geographic variation in caribou on the Canadian arctic islands

1982 ◽  
Vol 60 (10) ◽  
pp. 2442-2454 ◽  
Author(s):  
D. C. Thomas ◽  
P. Everson
Keyword(s):  
Geographic Variation ◽  
Rangifer Tarandus ◽  
Canadian Arctic ◽  
The Other ◽  
Long Bones ◽  
Body Measurements ◽  
Morphological Similarity ◽  
North Central ◽  
Barren Ground ◽  
Northern Regions

Analyses of body, leg bone, skull, and pelage data indicated a cline in the characters of caribou (Rangifer tarandus) from central Boothia Peninsula to the western Queen Elizabeth Islands. The main difference between the skulls of barren-ground caribou (R. t. groenlandicus) on central Boothia Peninsula and the more northerly Peary caribou (R. t. pearyi) was a shorter muzzle in the latter. Pelage tone was markedly lighter in Peary caribou and they were smaller in most body measurements, most notably in the length of long bones. Two major populations of Peary caribou were identified: one on the western Queen Elizabeth Islands (Parry Islands), the other on Somerset and Prince of Wales islands. Differences in skull size and form suggest that each population was composed of two or more subpopulations. The larger and darker R. t. groenlandicus occurred on north-central Boothia Peninsula and the two subspecies and apparent intergrades were present in winter on northern regions of the peninsula. The morphological similarity of Peary caribou on Somerset and Prince of Wales islands is explained by interisland movements resulting in genetic mixing. The same is true for caribou on the western Queen Elizabeth Islands and that population apparently has little genetic interchange with the other.

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