• Characterization of muskox habitat in northeastern Alaska

      O'Brien, Constance Marsha (1988-12)
      In northeastern Alaska, muskoxen have been most often found in riparian habitats and proximate uplands. Vegetation was studied in nine adjacent river drainages; six of the drainages are regularly used by muskoxen. Twenty-two vegetation/land cover types were described using aerial photographs, point-intercept sampling, and ocular cover estimates. The proportion of each cover type was estimated for each drainage and compared among drainages by MANOVA. There was no significant difference among non-muskox drainages in the average proportion of cover types. A marginally significant difference was found among muskox drainages. There were no significant differences in the proportions of each vegetation type in non-muskox drainages versus muskox drainages. Five vegetation types associated with high forage quality and availability and low snow accumulation were often used by muskoxen. Four of these five vegetation types typically had <7% cover in the nine drainages and are critical habitat components in northeastern Alaska.
    • Comparative patterns of winter habitat use by muskoxen and caribou in northern Alaska

      Biddlecomb, Mark Edward (1992-09)
      Snow depth and hardness strongly influenced selection of feeding zones, (i.e., those areas used for foraging), in late winter by both muskoxen (Ovibos moschatus) and caribou (Rangifer tarandus grand) in northern Alaska. Snow in feeding zones was shallower and softer than in surrounding zones. Depth of feeding craters was less than the average snow depth in feeding zones. Moist sedge tundra types were used most often by muskoxen, and their diet, based on microhistological analysis of feces, was dominated by graminoids. Moist sedge and Dryas tundra types were most often used by caribou; lichens and evergreen shrubs were the major constituents of their diet. Despite selection of moist sedge tundra types by both muskoxen and caribou in late winter, dietary and spatial overlap was minimal.
    • Effects of milk intake, growth and suckling efficiency on suckling behavior of muskox (Ovibos moschatus) calves

      Tiplady, Barbara Ann (1990-12)
      General theory on parental provisioning predicts that mammalian offspring receiving more milk should show longer suckling bouts, greater total suckling time, longer intervals between bouts, and greater suckling success. For muskoxen I found that suckling bout duration and suckling success were positively correlated with milk intake during some but not all stages of lactation. Neither interval between suckling bouts, nor total suckling time, was correlated with milk intake. Growth of calves was positively related to milk intake, and among calves of the same age suckling efficiency (intake/min suckling) was highly related to body weight. Therefore, milk intake affects growth rate, which in turn affects suckling efficiency. The overriding influence of calf body size and suckling efficiency limits interpretation of differences in suckling behavior that can be attributed to milk intake by muskox calves and therefore to the provisioning strategy of the cow.
    • Genetic variation in muskoxen (Ovibos moschatus)

      Fleischman, Claire L. (1986-05)
      Populations of Alaskan muskoxen (Ovibos moschatus) are derived from 34 animals transplanted from East Greenland in the 1930s. The possibility of a founder effect following this transplant was investigated. Muscle, liver and plasma samples from 87 Alaskan animals and 39 Greenlandic animals were analyzed using polyacrylamide and starch gel electrophoresis. A total of 38 enzyme and non-enzymatic protein systems, coded by 58 presumptive loci, was tested for activity; 28 loci were considered usable. One locus (Esterase-2) was polymorphic; the proportion of polymorphic loci was 0.036 (95% criterion). The mean heterozygosity per individual was 0.006 in the Greenlandic population and 0.011 in the Alaskan population. The allele frequencies at the Est-2 locus were similar in both populations. No heterozygote deficiency and no evidence of a founder effect were seen in the Alaskan population. This may be a consequence of the low level of allozymic variation seen in muskoxen in general.
    • Habitat relationships and activity patterns of a reintroduced musk ox population

      Jingfors, Kent T. (1980-12)
      A reintroduced muskox herd in arctic Alaska was studied over a 2-year period to assess seasonal changes in activity patterns and feeding behavior. This large herd showed high calving rates and early breeding in females, characteristic of a rapidly expanding population. Age- and sex-specific differences in activity budgets reflect seasonal energy demands of the different cohorts. Comparison with high arctic muskoxen shows that characteristics of suckling behavior provide a more sensitive indicator of differences in range quality than does variation in summer activity patterns. In summer, muskoxen appear to select vegetation types on the basis of abundance and phenological stage of preferred forage species; snow characteristics strongly influence habitat selection in winter. The herd remained within a limited home range with overlapping seasonal ranges and a distinct calving area. The restricted movements and conservative activity budgets permit minimization of energy expenditure and forage requirements, allowing for a year-long existence in areas of low primary productivity.
    • Reproductive behavior and related social organization of the muskox on Nunivak Island

      Smith, Timothy E. (1976-05)
      The sexual behavior and social organization of the muskox (Ovibos moschatus wardi Zimmerman) were studied on Nunivak Island, Alaska, in fall 1972 and summer and fall 1973. Observation effort was concentrated on a single harem group for two months, during the height of courtship activity. Movements and fluctuations in the structure of this group are documented. There was no significant change in mean herd size as a result of the rut, suggesting the existence of a basic social unit independent of the influence of harem bulls. Harem bulls were in the 6-10 year age class. They exerted a stabilizing influence on the harem but did not direct its movements. The rut extended from early July to mid-October. Copulation occurred on September 4 and 5. General patterns of sexual and agonistic behavior are described. Changes in activity patterns as a result of the rut are shown. Bulls displayed more marked changes than cows or juveniles. The proportion of time allocated to sexual and agonistic behavior increased at the expense of maintenance activity as the rut progressed.
    • Spatial scales of muskox resource selection in late winter

      Wilson, Kenneth J. (1992-05)
      I examined resource selection by muskoxen in late winter on the coastal plain of the Arctic National Wildlife Refuge, Alaska, by comparing use and availability at regional, meso, local, and micro spatial scales. Use of vegetation types for feeding appears to be based on selection of areas of shallow soft snow with high cover of sedges, dead vegetation, and total vegetation, and on selection against areas of little vegetation cover or deep hardpacked snow. Muskoxen used moist sedge, tussock sedge, and Dryas terrace tundra in proportion to availability and avoided barren ground, partially vegetated, riparian shrub, and Dryas ridge tundra. Selection for areas of shallow snow occurred within vegetation types as well as between vegetation types. Occurrence of sedges and grasses in the diet was greater than availability. Feeding zones were primarily on windblown vegetated bluffs; these areas are distributed in narrow bands along creeks, rivers, and the coastline.