Synchronicity of movement paths of barren-ground caribou and tundra wolves

Movement patterns of highly mobile animals can reveal life history strategies and ecological relationships. We hypothesized that wolves (Canis lupus) would display similar movement patterns as their prey, barren-ground caribou (Rangifer tarandus groenlandicus), and that movements of the two species would co-vary with season. We tested for interspecific movement dynamics using animal locations from wolves and caribou monitored concurrently from mid-October to June, across the Northwest Territories and Nunavut, Canada. We used a correlated random walk as a null model to test for pattern in movements and the bearing procedure to detect whether movements were consistently directional. There was a statistical difference between the movements of caribou and wolves (F _1,9 = 13.232, P = 0.005), when compared to a correlated random walk, and a significant interaction effect between season and species (F _1,9 = 6.815, P = 0.028). During winter, the movements of caribou were strongly correlated with the 80°–90° ( $\overline{X}$ X ¯ r = 0.859, SE = 0.065) and 270°–280° ( $\overline{X}$ X ¯ r = 0.875, SE = 0.059) bearing classes suggesting an east–west movement gradient. Wolf movements during winter showed large variation in direction, but were generally east to west. Peak mean correlation for caribou movements during spring was distinct at 40°–50° ( $\overline{X}$ X ¯ r = 0.978, SE = 0.006) revealing movement to the north-east calving grounds. During spring, wolf movements correlated with the 80°–90° ( $\overline{X}$ X ¯ r = 0.861, SE = 0.043) and 270°–280° ( $\overline{X}$ X ¯ r = 0.850, SE = 0.064) bearing class. Directionality of movement suggested that during winter, caribou and wolves had a similar distribution at the large spatial scales we tested. During spring migration, however, caribou and wolves employed asynchronous movement strategies. Our findings demonstrate the utility of the correlated random walk and bearing procedure for quantifying the movement patterns of co-occurring species.     

Prevalence of Toxoplasma gondii antibodies in barren-ground caribou (Rangifer tarandus groenlandicus) from the Canadian Arctic

Prevalence of antibodies to Toxoplasma gondii was determined in 147 barren-ground caribou (Rangifer tarandus groenlandicus) from 5 herds in the Northwest Territories and Nunavut, northern Canada, by the modified agglutination test (MAT). In the mainland herds (Bluenose, Bathurst, and Beverly), antibodies were found in 43 (37%) of 117 caribou, and MAT titers were 1:25 in 10, 1:50 in 24, and 1:500 in 9. In the island herds, only 1 (4.3%) of 23 animals sampled from the North Baffin Island herd was positive (titer = 1:25) and no antibodies were detected in 7 caribou from the Dolphin and Union herd. The high prevalence of antibodies to T. gondii in the mainland caribou herds indicates that caribou meat may contain viable T. gondii.     

Mandibular lesions in the Western Arctic caribou herd of Alaska.

Lesions were noted in 7.0 and 4.4% of mandible pairs collected from the Western Arctic caribou herd of northwestern Alaska in 1959-61 and 1975-77, respectively. The prevalence of mandibular lesions in the 1959-61 collection is believed to be the highest reported in wild caribou herds of North America. The frequency of occurrence of mandibular lesions was highest in caribou 7 years of age and older, and there was a higher prevalence in adult males than in adult females. Trauma, dental abscesses, and periodontal disease were the probably cause of most lesions. Pathogenic bacteria were not isolated from mandibular lesions from an 11 year-old female. Thirty-three of 98 (33.7%) mandibles with lesions were missing one tooth, while ten (10.2%) were missing more than one tooth. The first molar (M1) was the most common tooth lost in association with lesions, although the loss of two or more teeth was more common among premolars than among molars.     

Comparison of gross visual and microscopic assessment of four anatomic sites to monitor Besnoitia tarandi in barren-ground caribou (Rangifer tarandus)

The objective of this study was to establish a standardized protocol to monitor Besnoitia tarandi prevalence and intensity in barren-ground caribou (Rangifer tarandus) herds by: 1) calculating the relative sensitivity and specificity of the gross visual assessment of four anatomical sites compared with microscopic evaluation, and 2) determining which of four anatomical sampling sites was the most sensitive for detecting B. tarandi cysts by microscopy. Sampled tissues consisted of the conjunctiva of the left eye and skin sections from the rostrum, metatarsus, and thigh from 312 harvested caribou. Diagnosis of infection with B. tarandi was based on observation of at least one cyst by microscopic examination. For each tissue, the maximal density of cysts (number of B. tarandi cysts/mm(2) in the section examined) was calculated for a measured area consisting of the dermis extending from the epidermis of the skin to the base of the hair follicles and adnexal structures. For the conjunctiva, the entire submucosa was evaluated. Gross visual evaluation markedly underestimated B. tarandi prevalence in caribou with a relative sensitivity ranging from 0.29 in the conjunctiva to 0.13 in the skin section from the thigh, whereas relative specificities ranged from 0.98 to 1.00. The metatarsus and rostrum skin sections had the highest probabilities of cyst detection of all four anatomical sampling sites. The metatarsus harbored significantly higher densities of B. tarandi cysts than the rostrum, thigh, or conjunctiva. In conclusion, microscopic evaluation of a skin section from the anterior aspect of the mid-third portion of the metatarsal region could be used as a standardized comparative indicator of density of B. tarandi infection in Rangifer.     

A standardized x-ray examination of mandibular fractures

Proceeding from an x-ray examination of 143 patients with mandibular fractures, the most informative methods and projections as well as the order of their use with account of the site of a fracture, were determined. The most informative method in all fracture sites was orthopantomography; panoramic roentgenography was indicated only in fractures of the frontal part. If panoramic tomography cannot be done, roentgenography or electroroentgenography in the frontal-nasal projection is recommended. If panoramic roentgenography cannot be done, extraoral roentgenography is indicated in the diagnosis of fractures of the frontal part of the mandible.     

Besnoitiosis in a woodland caribou

Besnoitiosis was diagnosed in an adult male woodland caribou found dead in northern Saskatchewan. The lesions present were comparable to those of chronic besnoitiosis in cattle, and were much more severe than those previously described in domestic reindeer and barren-ground caribou.     

Prion protein genes in caribou from Alaska

Prion protein genes were sequenced in free-ranging Alaska caribou (Rangifer tarandus grantii). Caribou prion alleles are identical or nearly so to those of wapiti, white-tailed deer, and mule deer. Five single-nucleotide polymorphisms were detected with substitutions at residues 2 (V-->M), 129 (G-->S), 138 (S-->N), 146 (N-->N), and 169 (V-->M). The 138N codon had been previously reported only in prion pseudogenes of other cervids. In caribou, the 138S and 138N alleles are present at frequencies of approximately 0.7 and 0.3, respectively, and they are seen in both homozygotes and heterozygotes of three geographically separated herds, each a component of the continental metapopulation. Genetics seems to permit the spread of chronic wasting disease from middle-latitude deer to high-latitude caribou in North America.