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

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.

1985 ◽  
Vol 63 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Frank L. Miller ◽  
Anne Gunn ◽  
Eric Broughton

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.


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

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.


1978 ◽  
Vol 56 (8) ◽  
pp. 1684-1696 ◽  
Author(s):  
T. Charles Dauphiné Jr.

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.


Rangifer ◽  
1997 ◽  
Vol 17 (1) ◽  
pp. 44
Author(s):  
Otto Blehr

The behaviour of single, and small bands of caribou (Rangifer tarandus groenlandicus) when confronted by humans was compared with the energy—saving behaviour zoologists have ascribed to caribou in encounters with non-hunting wolves (Canis lupus). When confronted by me, or upon getting my scent, caribou ran away on all occasions. Their flight was occasionally interrupted by short stops to look back in my direction, but would continue on all occasions until they were out of sight. This behaviour is inconsistent with the one ascribed to caribou by zoologists when the intruder is a wolf instead of a human. In their view, the caribou stop their flight soon after the wolf gives up the chase, and accordingly save energy owing to their ability to distinguish between hunting and non-hunting wolves. However, small bands of caribou, as well as single animals, have never been observed to behave in this manner. On the contrary, the behaviour of caribou in such encounters is known to follow the same pattern as in their encounters with humans. Energy—saving behaviour is, however, sometimes observed when caribou become inquisitive about something in their surroundings. They will then readily approach as well as try to get down-wind of the object. When the object does not induce fear, it may simply be ignored, or charged before the caribou calm down. The effect of this "confirming behaviour" is that energy which would otherwise have been spent in needless flights from non-predators is saved.


Rangifer ◽  
2016 ◽  
Vol 36 (1) ◽  
pp. 1 ◽  
Author(s):  
Keri McFarlane ◽  
Anne Gunn ◽  
Mitch Campbell ◽  
Mathieu Dumond ◽  
Jan Adamczewski ◽  
...  

Migratory barren-ground caribou (Rangifer tarandus groenlandicus) provide an opportunity to examine the genetic population structure of a migratory large mammal whose movements and distribution, in some instances, have not been heavily influenced by human activities that result in habitat loss or fragmentation. These caribou have likely reached large effective population sizes since their rapid radiation during the early Holocene despite cyclic changes in abundance. Migratory barren-ground caribou are managed as discrete subpopulations. We investigated genetic variation among those subpopulations to determine the patterns of genetic diversity within and among them, and the implications for long-term persistence of caribou. We identified three distinct genetic clusters across the Canadian arctic tundra: the first cluster consisted of all fully-continental migratory barren-ground subpopulations; the second cluster was the Dolphin and Union caribou; and the third cluster was caribou from Southampton Island. The Southampton Island caribou are especially genetically distinct from the other barren-ground type caribou. Gene flow among subpopulations varied across the range. Occasional gene flow across the sea-ice is likely the reason for high levels of genetic variation in the Dolphin and Union subpopulation, which experienced very low numbers in the past. These results suggest that for most migratory caribou subpopulations, connectivity among subpopulations plays an important role in maintaining natural genetic diversity. Our analyses provide insight into the levels of microsatellite genetic diversity and patterns of gene flow that may be common to large subpopulations that historically had a continuous distribution across a large continental range. These data can also be used as a benchmark to compare the effects of habitat fragmentation and bottlenecks on other large caribou populations.


ARCTIC ◽  
2015 ◽  
Vol 68 (4) ◽  
pp. 407 ◽  
Author(s):  
Jan Adamczewski ◽  
Anne Gunn ◽  
Kim G. Poole ◽  
Alexander Hall ◽  
John Nishi ◽  
...  

The Beverly herd was one of the first large migratory herds of barren-ground caribou (Rangifer tarandus groenlandicus) defined in northern Canada on the basis of annual return of breeding females to traditional calving grounds near Beverly Lake in Nunavut. In 1994, herd size was estimated at 276 000 ± 106 600 (SE) adult caribou, but monitoring was minimal from 1994 to 2007. The next calving ground survey in 2002 revealed that caribou densities had dropped by more than half since 1994; annual surveys following from 2007 to 2009 demonstrated an extreme decline in numbers of calving cows, and by 2011, no newborn calves were seen there. We examine two possible explanations for the declining use of the traditional Beverly calving grounds from 1994 until their abandonment by 2011. One explanation is that a true numerical decline in herd size occurred, driven in at least the later stages by low cow survival and poor calf productivity, which led the remaining Beverly cows to switch to the neighbouring Ahiak calving ground 250 km to the north in 2007 – 09 and join that herd. An alternative explanation is that the decline on the traditional Beverly calving grounds was largely due to a distributional shift to the north of the Beverly herd that may have begun in the mid-1990s. We suggest that the former explanation is the more likely and that the Beverly herd no longer exists as a distinct herd. We acknowledge that gaps in monitoring of Beverly and Ahiak caribou hamper definitive evaluation of the Beverly herd’s fate. The large size sometimes achieved by barren-ground caribou herds is not a guarantee of persistence; monitoring shortfalls may hamper management actions to address declines.


1970 ◽  
Vol 48 (5) ◽  
pp. 1023-1027 ◽  
Author(s):  
E. Broughton ◽  
L. P. E. Choquette ◽  
J. G. Cousineau ◽  
F. L. Miller

Serum samples from 1692 reindeer slaughtered in the Mackenzie River Delta in the last decade and from 320 Kaminuriak barren-ground caribou killed between June 1966 and July 1968 were tested for brucellosis. All sera yielding titers of 1:25 or higher were considered to be positive. A positive reaction was obtained in 148 of the 1692 reindeer and 14 of the 320 barren-ground caribou tested, giving an overall reactor percentage of 8.74 in reindeer and 4.37 in caribou.Orchitis, epididymitis, bursitis, metritis, abortion, and placental retention—conditions associated with brucellosis in reindeer in the U.S.S.R. and caribou in Alaska—were not noted in the autopsy of the 1692 reindeer and of 500 sexually mature barren-ground caribou. Three possible records of bursitis, of unknown nature, in barren-ground caribou are discussed. Seemingly, brucellosis does not represent a serious threat to either the Mackenzie River Delta reindeer or the Kaminuriak barren-ground caribou population, but its detection in these animal populations is of interest from a public health standpoint.


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