Peary caribou and barren-ground caribou COSEWIC assessment and status report: chapter 6

Classification

Phenotypes

Peary caribou were formally described in 1902 from a specimen collected on northeast Ellesmere Island (Allen 1902, 1908). Anderson (1934) gave their range as from Greenland to the mainland, including Victoria Island. Anderson (1946) maintained Allen’s (1902, 1908) classification of Peary caribou as R. pearyi. He gave their range as Ellesmere Island, Sverdrup Island and “probably” other islands in the northern part of the Canadian Arctic Archipelago (from which he had no specimens), while assigning to barren-ground caribou (R. a. arcticus) those populations in “the southern fringe of islands north of the mainland coast,” as well as the mainland.

On the basis of skull dimensions (19 measurements) and skull shape (14 measurements), Manning (1960) found a stepped clinal distribution from the smallest caribou in the Queen Elizabeth Islands through Banks Island to the Dolphin and Union herd of Victoria Island, to mainland caribou, with the largest step being the last. The Dolphin and Union herd formerly migrated annually between Victoria Island and the adjacent coastal mainland across Coronation Gulf, but was apparently reproductively isolated from mainland caribou because of the timing and location of the rut on southern Victoria Island. The distribution and darkness of brown versus white pelage paralleled that of the skeletal measurements, the lighter animals being in the north. Hoof size and shape completely separated Queen Elizabeth Islands caribou from mainland caribou, but Manning had no hooves from Banks and Dolphin and Union animals. Within the Queen Elizabeth Islands group, there were no differences in these characteristics from widely separated locations from Prince Patrick and Melville islands in the southwest to Ellesmere and Axel Heiberg islands in the northeast, a distance of some 1100 km. In addition to these groups, there were also resident caribou on Victoria Island that did not migrate; Manning (1960) was unable to include these in his analysis because he had only 1 ambiguous specimen. On the basis of skull and hoof measurements and pelage and antler velvet colour, Manning (1960) referred the Banks Island caribou to R. a. pearyi (now R. t. pearyi) and the Dolphin and Union herd tentatively to R. a. arcticus (now R. t. groenlandicus), barren-ground caribou.

Manning and Macpherson (1958: 221-222) reported local accounts that both arcticus and pearyi occur on Somerset Island, but that there is no intergradation between them. Most of the mainland caribou are migratory, moving northward over Boothia to Somerset Island before break-up, and southward again before, during, and after freeze-up, but some remain on Somerset Island all winter and would therefore be in contact with pearyi during the rutting season. A few mainland caribou sometimes visited Prince of Wales Island.

Banfield (1961) returned the species designation to R. tarandus. Otherwise he maintained Manning’s (1960) classification and distribution of phenotypes, with the inclusion of caribou along the northwestern tip of Victoria Island as R. t. pearyi on the basis of Aboriginal traditional knowledge. He noted that the Prince of Wales population of R. t. pearyi is unique in having typical pearyi skeletal and pelage characteristics, but a larger size: a “super pearyi deme”. He accepted “Eskimo and European reports” that Peary caribou cross between Prince of Wales and Somerset Island, and that although mainland caribou occasionally stray to these islands, they remain reproductively isolated. He noted the occurrence of “typical groenlandicus” on the Boothia and Adelaide peninsulas. His maps (1961: 46, 48) show the Boothia Peninsula and southern Victoria Island as having been occupied by barren-ground caribou and northern Victoria Island with Peary caribou up to the end of the 19th century but vacant except for Peary caribou along the northwestern coast at the date of publication.

Banfield (1974) maintained the same classification and distribution, showing Victoria Island and the adjacent mainland coast vacant except for the northwestern tip, which is occupied by Peary caribou.

Thomas et al. (1976, 1977) and Thomas and Broughton (1978) measured femur length in caribou in the western Queen Elizabeth Islands and the Prince of Wales-Somerset group and concluded that although there were inter-island differences, all were Peary caribou.

Thomas and Everson (1982) took caribou skeletal measurements from the Boothia Peninsula and concluded that they ranged from “the typical R. t. pearyi phenotype to the typical R. t. groenlandicus phenotype.” They also described a stepped cline in skull measurements with the western Queen Elizabeth Islands (55 adult skulls from Prince Patrick, Melville, and Bathurst islands) forming a relatively homogenous group compared to 35 adult skulls collected from Prince of Wales and Somerset islands. Their skull measurements and pelage colour of caribou from Boothia Peninsula supported at least 2 types of caribou there.

To determine whether the caribou newly inhabiting Victoria Island were the same as those from the historic Dolphin and Union herd, Gunn and Fournier (1996) collected 55 skulls near Cambridge Bay. They compared them to published information on specimens from Melville Island, Boothia Peninsula, Prince of Wales Island, the type specimens of Dolphin and Union caribou collected by Anderson (1934) in 1915–1916 and barren-ground caribou from near Pelly Bay. The Victoria Island skulls were intermediate in size between those from Melville and Prince of Wales islands. There were no significant differences in skull measurements between the new series and the 1913–1916 series except for nasal length, which the authors attributed to a difference in measurement technique. They concluded that the extant caribou there were the same as the historic Dolphin and Union herd.

Gunn (2003) reviewed the pelage and morphometric measurements and analysis and the distribution of specimens used by the early taxonomists. She noted that, of all the physical characteristics, pelage colour patterns and antler velvet were not clinal or stepped as are skull and skeletal measurements, but instead were relatively homogenous within the Arctic islands (including the Dolphin and Union caribou) and showed a discontinuous distribution with respect to mainland caribou.

Genotypes

Gravlund et al. (1998), using mitochondrial DNA sequences from the 3 circumpolar, small-bodied caribou subspecies, including 15 specimens from the Canadian Arctic Archipelago, found that R. t. pearyi and R. t. eogroenlandicus shared a haplotype, which was not found in other clades and was common in R. t. pearyi. They concluded that R. t. platyrhynchus evolved convergently from large-bodied Eurasian reindeer. They have shown that the small-bodied caribou are at least diphyletic and possibly even polyphyletic.

Eger et al. (1999, 2003), used mitochondrial DNA for caribou from 13 locations in Canada and Alaska, including 6 locations in the range of Peary caribou: Bathurst Island, Prince Patrick Island, Banks Island, Prince of Wales Island, Somerset Island, and the Boothia Peninsula. They found evidence of ancient divergence between northern caribou of Beringia and those of eastern Canada. Analysis of molecular variance indicated that the subspecies, R. t. pearyi as defined by Banfield (1961), is not monophyletic (Eger et al. 2003). They suggest that there were 3 distinct sources (refugia) of caribou in North America: Alaska, south-eastern North America, and the High Arctic (Eger et al. 2003).

Røed et al. (1986) analysed blood protein transferrin type frequencies in several populations of small-bodied, Arctic island caribou and concluded that the Prince of Wales–Somerset caribou were predominately pearyi , although there were significantly different frequencies between them and those from the Queen Elizabeth Islands.

Zittlau et al. (2003) used microsatellite DNA analyses and larger sample sizes from Melville Island, the Bathurst Island complex, Banks Island, northwestern Victoria Island, south-central Victoria Island (the Dolphin and Union herd), the Prince of Wales Island-Somerset islands group and the Boothia Peninsula to assess distinctiveness and genetic variation among Peary caribou populations. They found that:

  • The Banks Island and northwestern Victoria Island populations are not significantly different from each other, indicating past and/or recent movement between these islands; however, the lack of difference may also result from the small sample size from northwestern Victoria Island.
  • The next most closely related populations are those on Melville Island, the Bathurst Island complex and the Prince of Wales-Somerset Island complex (indicating movements among these groups over a time scale of ~1000 years).
  • The Boothia Peninsula and Banks Island populations are closely related, but the Boothia population that was sampled is strongly differentiated from the Prince of Wales-Somerset population.
  • The Dolphin and Union caribou are the most differentiated from the other Arctic island populations and are also distinct from barren-ground caribou of the adjacent mainland. The Dolphin and Union caribou also cross-assigned the least, suggesting little genetic exchange with other groups.

These relationships are illustrated in Figure 6. The unrooted neighbour-joining tree of Nei’s standard genetic distance Ds for Arctic islands and neighbouring caribou populations is shown in Figure 7. These results agree with the occurrence of a single refugium for the progenitors of barren-ground and Peary caribou during the Wisconsin glaciation, about 20 000 years before present. Arctic island forms later differentiated from barren-ground caribou and, to a lesser extent from each other.

Figure 6. Assignment test results based on micro-satellite DNA frequencies in Peary/Dolphin and Union and barren-ground caribou (Zittlau et al. 2003). Values (y axis) indicate the percentage of caribou in each population (x axis) assigned to each potential source population (legend).

Figure 6.  Assignment test results based on micro-satellite DNA frequencies in Peary/Dolphin and Union and barren-ground caribou (Zittlau et al. 2003).Values (y axis) indicate the percentage of caribou in each population (x axis) assigned to each potential source population (legend).

Figure 7. Neighbour-joining tree of genetic distances (Zittlau et al. 2003).

Figure 7.  Neighbour-joining tree of genetic distances (Zittlau et al. 2003).

Considering the available evidence as summarized above, participants at a caribou genetics and relationship workshop, held in Edmonton in February 2003, (Strobeck 2003) concluded that there are 5 distinct populations (or metapopulations) of Peary-type caribou:

  • Western Queen Elizabeth Islands,
  • Prince of Wales-Somerset islands,
  • the Boothia Peninsula,
  • Banks Island-northwestern Victoria Island, and
  • Dolphin and Union (distinct from both Peary and barren-ground caribou).

Although there have been no DNA samples of caribou from the eastern Queen Elizabeth Islands analysed for genetic relationships, based on morphology, they group with western Queen Elizabeth Islands caribou.

Summary of taxonomy

Pending a revision of the genus, all caribou north of the mainland, except for the Dolphin and Union herd and the barren-ground caribou on Baffin Island and those on the islands in Foxe Basin and Hudson Bay, should be referred to as Peary caribou. Peary caribou also occur on the Boothia Peninsula (which they share with barren-ground caribou) and sporadically on adjacent parts of the mainland.

The Dolphin and Union herd remains problematic. Their behavioural, morphometric (skeletal characteristics), and genetic affinities lean toward barren-ground caribou, R. t. groenlandicus, as per Anderson (R. t. arcticus: 1946), Manning (1960) and Banfield (1961, 1974), from which, however, they are clearly distinct. Their pelage and antler velvet colour make them look more like Peary caribou (Gunn 2003). Some biologists, Inuit, and Inuvialuit recognize them as Peary-type or island caribou as opposed to barren-ground or mainland caribou. A. Gunn (Government of the Northwest Territories, pers. comm. July 3, 2003) notes that, “Genetically and phenotypically, the Dolphin and Union caribou appear so different [from barren-ground caribou] that in the context of diversity it is misleading to label them as barren-ground. The original taxonomic description was based on only a few museum skulls and hides rather than the living caribou and current genetic techniques.” Pending a revision of the species, however, there is no justification for re-classifying them as R. t. pearyi.

Population designations

Although a single assessment is applied to all Peary caribou in Canada, 4 populations can be recognized, in addition to the Dolphin-Union caribou. These population are shown in Table 1 and described in the following sections.

Queen Elizabeth Islands

The western Queen Elizabeth Islands have 24% of the land mass, or 98 651 km², and include 2 island complexes within which caribou exhibit regular, inter-island seasonal movements. There have also been past (based on genetic similarities) and recent, but limited, inter-island movements of caribou between these 2 complexes:

  • the Melville Island complex, 61 237 km², consisting of Melville, Prince Patrick, Eglinton, Byam Martin and Emerald islands; and the Prime Minister Group, 8606 km², which includes the islands of Mackenzie King, Borden and Brock.
  • tthe Bathurst Island complex, 28 808 km², consisting of Bathurst, Cornwallis, Lougheed, Vanier, Cameron, Alexander, Massey, Little Cornwallis, Helena, Baillie-Hamilton, Griffith and Lowther islands.

The eastern Queen Elizabeth Islands have 76% of the landmass, about 318 089 km², based on 14 islands each > 130 km². The complex includes Ellesmere, Devon, Axel Heiberg, Ellef Ringnes, Amund Ringnes, Cornwall, Graham, Meighen, King Christian, North Kent, Coburg, Stor, Hoved, and Buckingham islands, as well as associated lesser islands. Much (about 34%, ca. 110 000 km²) of Ellesmere, Devon, and Axel Heiberg islands are covered with ice caps and permanent snow fields.

Table 1. Summary of Arctic islands caribou populations and 1991 COSEWIC designations
Population Latin name COSEWIC nameTable notea COSEWIC designationTable notea Extent of Occurrence
Queen Elizabeth IslandsTable noteb Rangifer tarandus pearyi High Arctic population Endangered 20 main western islands > 130 km² totalling 98 651 km² and 14 main eastern islands totalling 318 089 km²): 416 740 km² total of the main islands, 419 061 km² total of all islands
Banks Island-northwestern Victoria Island Rangifer tarandus pearyiTable notee Banks Islandpopulation Endangered Banks Island (70 028 km²) and northwestern Victoria Island
(21 874 km²)
Prince of Wales-Somerset Rangifer tarandus pearyi Low Arctic population Threatened Prince of Wales Island (33 339 km²), Somerset Island (24 786 km²), Russell Island (940 km²) and nearby islands
Boothia PeninsulaTable notec Rangifer tarandus pearyi Low Arctic population Threatened Boothia Peninsula (32 328 km²)
Dolphin & Union Rangifer tarandus groenlandicusTable noted Low Arctic population Threatened Victoria Island less northwestern Victoria Island (195 417 km²) and Stefansson Island (4463 km²)

Many caribou in the Melville complex winter on Prince Patrick Island and move in spring to Eglinton, Emerald, Melville, and Byam Martin islands for the summer (Miller et al. 1977b, Gunn and Dragon 2002). Regular inter-island movements are also known for the Bathurst complex (Miller 1990a, Miller 1995, Miller 2002).

Banks Island–northwestern Victoria Island

The population includes a complex of local populations. Peary caribou on Banks Island move to the northwest to calve and there is likely a second calving area on the east-central coast around Jesse Bay, based on local knowledge and aerial surveys (Manning and Macpherson 1958, Urquhart 1973, Wilkinson and Shank 1974, Fraser et al. 1992, Nagy et al. 1996).

In some winters, Inuvialuit see caribou migrating between Victoria and Banks islands (Elias 1993). In the 1960s caribou from Banks Island migrated to northwestern Victoria Island, where they thrived. In some years, however, so many cross from Victoria Island to Banks Island that few are left on Victoria Island (north of Minto Inlet). During the 1990s, when caribou numbers were low, the inter-island movements were

infrequent. Peary caribou on northwestern Victoria Island migrate north in spring to calve and south to the Minto Inlet area in winter (Gunn and Fournier 2000).

A few Peary caribou have sporadically appeared on the mainland as far west as Old Crow, Yukon, during or shortly after exceptionally severe environmental years on Banks Island and/or on Victoria Island (Manning and Macpherson 1958, Banfield 1961, Youngman 1975). Youngman (1975) reported that Kutchin (Dene) hunters from Old Crow often commented on the occasional small caribou mixed with herds of larger animals.

Dolphin and Union Strait

Anderson (1913, 1934) described and collected specimens from a large migratory herd that summered on Victoria Island and crossed the Dolphin and Union Strait to winter on the mainland around Coronation Gulf.

Inuvialuit from Holman recognize two kinds of caribou on Victoria Island that differ in size, colour, and taste: Peary caribou of the northwest and “mainland caribou” (i.e., Dolphin and Union caribou) that summer on the central, southern and eastern parts (Elias 1993). Somewhat confusingly, Inuit from Cambridge Bay also distinguish Peary and mainland caribou, but in this case the “Peary caribou” are the Dolphin and Union herd and the mainland caribou are barren-ground caribou that do not cross to Victoria Island (i.e., the Bathurst Inlet, Bluenose or Ahiak herds of R. t. groenlandicus). Inuit from Victoria Island are also aware of migratory and non-migratory island caribou on Victoria Island.

Most of what is known of the population’s previous life history and numbers comes from Aboriginal traditional knowledge including the following sources:

  • Recorded by early naturalists such as Jennes (1922) and Anderson (1913, 1922) and summarized by Manning (1960);
  • Recorded by Elias (1993) through formal interviews; and
  • Recorded by the Inuvialuit Game Council (Inuvialuit Game Council 2002b, 2002a) during workshops in communities on Banks and Victoria islands.

Before about 1920, when they were still abundant, they crossed Dolphin and Union Strait at various points west as far as Cape Bexley and Coronation Gulf east to Queen Maud Gulf in the spring. They moved rapidly northwards to the north coast and spread out over most of the island. Some, perhaps 2000, remained on the Wollaston Peninsula during the summer, while the main herd continued north past Prince Albert Sound. Around 20 000 went further west. Some may have crossed to Banks Island. In the autumn, after the rut, they returned to the mainland south of Coronation Gulf and west at least to Cape Dalhousie.

When the migration ended by the early 1920s, the herd was assumed to be nearly extinct (Manning 1960, Banfield 1974), although 1000 were reported on Victoria Island in 1949 (Banfield 1950). Inuit from Cambridge Bay reported that they were still seeing caribou on southern Victoria Island, but rarely until the 1970s and 1980s when their numbers began to increase; by 1993 up to 7000 were migrating annually across Coronation Gulf and Dease Strait (Gunn et al. 1997, Gunn and Nishi 1998, Gunn and Fournier 2000). The skull measurements, pelage colour, and migratory behavior of caribou on southern Victoria Island in the 1980s were similar to those previously described by Manning (1960) for the Dolphin and Union herd (Gunn and Fournier 1996). Genetic evidence also supports its distinctiveness and genetic isolation from other populations (Zittlau 2003).

Currently most of the central/southern/eastern Victoria Island caribou migrate to the mainland in winter but some do not. Elias (1993) summarized Aboriginal traditional knowledge that the resident Victoria Island caribou migrate north of Prince Albert Sound to calf in the spring; they winter around there or on islands to the east or south of the coast. Some of those caribou cross to Read Island, while others go east to Cambridge Bay. Those that migrate across the sea ice to the mainland in November, winter in the area of Elu Inlet, and then return in April to southeast Victoria Island.

Prince of Wales Island–Somerset Island

Large-scale (involving hundreds of caribou) east–west movements occur between winter range on Somerset Island and calving areas on Prince of Wales Island and their satellite islands such as Pandora, Prescott, Vivian, and Lock, but these do not involve all the caribou, and use of the various islands differs among years (Miller and Gunn 1978, 1980, Miller and Kiliaan 1980, 1981, Miller et al. 1982, Miller 1990a, Miller 1991, Miller 1997a). Lesser (in terms of numbers; some were regular migrations) movements were north-south between Prince of Wales Island and the nearby Mecham, Russell, Hamilton, Young, and Lowther islands in Barrow Strait, inferred by tracks on sea ice and by changing densities of caribou on the smaller island. After extensive searching by helicopter for caribou or caribou tracks crossing Barrow Strait to Bathurst, Cornwallis, or Little Cornwallis islands during 1977-1980, Miller (1990a) concluded that no regular, large-scale movements occurred between the Prince of Wales–Somerset group and the Queen Elizabeth Islands. These observations are consistent with the recent genetic results reviewed above that showed the Prince of Wales–Somerset and Queen Elizabeth Islands populations to be distinct, albeit with some past and possibly current movement between them.

Tracks on sea ice of Franklin Strait also indicate smaller-scale spring migrations directly from Boothia Peninsula to Prince of Wales Island and from Somerset Island to Prince of Wales Island on Peel Sound (Miller and Gunn 1978, 1980, Miller et al. 1982, Miller 1990a). The migrations allow those caribou to winter on Somerset Island and/or Boothia Peninsula, then summer and calve mainly on Prince of Wales Island but also on Somerset Island and Russell Island. A few also summer on lesser satellite islands in the Prince of Wales Island-Somerset Island-Boothia Peninsula Complex.

Boothia

Formerly considered part of a metapopulation together with the caribou of Prince of Wales and Somerset islands (Gunnet al. 2000b), at least some of the caribou on the Boothia Peninsula are now known to be genetically distinct. Like the Dolphin and Union herd, caribou on the Boothia Peninsula essentially disappeared and then reappeared during this century (Gunn 1998a). However, the Boothia Peninsula caribou populations are not clearly understood.

Both Peary and barren-ground caribou occur on the Boothia Peninsula. Peary caribou calve on the northwest of the peninsula and then summer there or move to southern Somerset Island or Prince of Wales Island before returning to around Taloyoak for the winter; however, the barren-ground local population calves on the northeast, summers there and returns to south of Taloyoak for the winter (Gunn 1998a). During the winter, hunters from Taloyoak found Peary caribou from Taloyoak to Thom Bay and Nalluqtaq Inlet to Brentford Bay (David Tucktoo pers. comm. 1986 cited by Gunn 1998a). Gunn et al. (2000a) found that Peary caribou fitted with satellite transmitters on northwestern Boothia Peninsula occurred throughout the peninsula in the course of the year and wintered on the mainland at least as far south as the Hayes River, about 350 km south of the Boothia isthmus.

Other islands

King William and other nearby islands near the Boothia Peninsula have uncertain status in terms of caribou subspecies and populations. Miller (1991) cited Gunn’s personal communication of 1989, reporting only a handful of “Peary-like” caribou there in 1989, and that Inuit hunters recognize both Peary-like immigrants and barren-ground migrants from the Boothia Peninsula and the mainland. Their taxonomic status is uncertain, and may comprise a mixture of Peary caribou, Dolphin and Union barren-ground and mainland barren-ground caribou.

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