Monitoring Caribou/Reindeer

Abundance surveys

Abundance monitoring is done by helicopter survey about every 5th year. These are carried out by scientists from the Greenland Institute for Natural Resources with assistance from hunting officers and local hunters (Figure 2). Only the four major West Greenland herds are surveyed. These include the KS, AM, Ameralik and QEQ herds. Results include estimates of abundance, herd structure and distribution.

Harvest monitoring

Annual harvest monitoring of the 11 Greenland caribou/reindeer populations is achieved through hunter reports from local hunters. Information on hunter reports includes the location, sex, age (calf, juvenile, adult) and rump fat depth of each caribou. If a cow, whether she had a calf-at-heel is also requested. This data may provide information about trends within each herd, however, recent analyses illustrated widespread inaccuracies in the fat depth and age data. In 1995 all jawbones from the harvest were collected and used to examine sex, age and body size of harvested animals. Differences in jawbone length in animals of the same age reflect differences in range quality, quantity and availability, i.e., when the animal was young. The total number of caribou harvested annually in Greenland, all herds combined, is available (in Danish or Greenlandic) from the Greenland Self Rule’s website for the Department of Fisheries, Hunting and Agriculture.


Health and body condition

Intensive scientific monitoring of cow body size / condition, health and reproduction using CARMA protocols is performed about every decade on the two largest herds in West Greenland, the Kangerlussuaq-Sisimiut (KS) and the Akia-Maniitsoq (AM). Intensive scientific monitoring was done in 1996, 1997, 2008 and 2009. These are exclusively cow collections, although calves-at-heel may also be taken. The health and body condition of cows are major determinants of calf recruitment and future trends in herd abundance, and therefore vital to caribou management in Greenland.

Akia-Maniitsoq (AM) and Kangerlussuaq-Sisimiut (KS)

We collected 41 caribou cows and 6 calves from the AM in 2008, and 40 caribou cows and 10 calves from KS in 2009. Initial data collected included; date, location, elevation, sex, age classification (calf, sub-adult (<3-years) or adult) and the presence, absence and condition of antlers, calf-at-heel, milk in udders or calf antlers and gross body measurements. A photo record for each animal was kept. Important parameters included body, bone, fat and organ weights and measurements, tooth wear, and body condition score. Samples collected included blood, muscle, liver, kidney, urine, rumen contents, bone marrow, bone (mandible, metatarsus), ovaries, foetal tissues, feces, abomasums, small intestine contents, milk, and hair. We checked for a variety of parasites including protozoa, nematodes, tapeworms, flukes and flies. Information and further data from the study is still under analysis and will be published afterwards.

Figure 3. Satellite collared female, Akia-Maniitsoq herd. Photo: C. Cuyler.

Satellite collaring

In 1997 eight caribou cows in the Akia-Nordlandet region of the Akia-Maniitsoq caribou population were captured and equipped with satellite collars. Two years of data made clear that some cows were stationary with annual movements of ca. 10 km along elevation gradients, while others were migratory with annual movements of up to a maximum of 170 km between winter and calving ranges. All movements appeared to be individual rather than synchronized as an aggregated herd. Regardless, before calving pregnant females moved to areas close to the Greenland Ice Cap, or to high elevations. In May 2008, 40 caribou cows from the Akia-Maniitsoq population were equipped with satellite collars (Fig. 3). The information obtained is still under analysis.

Figure 4. Bot larvae located deep in the caribou’s throat. Photo: B. White

Figure 5. Warbles. Photo: B. White

Parasites – Warbles and Bots

The warbles and bots have a yearly life cycle. Briefly, in winter they live as larvae inside their caribou / reindeer host, they exit in May-June to pupate for ca. 41-47 days, and by July and August the adult flies are ready to mate and start the process again. Warble and bot flies look alike. The adult flies do not eat, but just mate and then find a caribou / reindeer for their larvae. The presence of warble and bot flies can make for some spectacular avoidance behavior among caribou, i.e., they panic, especially if it is a bot fly. The bot fly female injects live larvae into the caribou’s nose. These larvae wriggle about in the nasal passages and finally end up in the throat where they anchor themselves by ‘hooks’ in the throat pouches (Fig. 4). In contrast, warbles lay their eggs on caribou hairs, these eggs hatch after a few days and crawl down the hair to penetrate the skin and live inside the caribou for about three months before encapsulating under the skin along the back and boring their breathing holes through the skin. The skins of caribou taken in mid-winter are often full of fat warble larvae (Fig. 5). However, by August-September the warble larvae are long gone leaving only the scars. Warbles can be ca. 3 cm long when they leave their host. When skinning an autumn caught caribou, hunters can see the holes, or scars of healed holes, on the inside of the skin especially along the back where warble larvae lived the previous winter. The bot larvae are harder to detect because they overwinter in the caribou’s throat. Come May-June they crawl out the nasal passages or are coughed out by the infected caribou.