Muskoxen Ovibos Moschatus Research Articles

Recent enrichment of megafauna in the north of Eurasia supports the concept of Pleistocene rewilding

‘Pleistocene rewilding' refers to the concept of restoring ecosystems to their state during the Pleistocene epoch, by (re‐)introducing species or their close relatives that were present during that time, in an effort to revive ecological processes that existed before human‐driven extinctions. This concept is highly controversial for both ethical and ecological reasons. Here I review evidence of recent northward range expansions of various large land mammals in boreal Eurasia, and discuss whether this provides evidence that rewilding projects might be justified and feasible. Around 100 years ago, the native boreal fauna of Eurasia included five species of large land mammals: moose Alces alces, brown bear Ursus arctos, wolf Canis lupus, reindeer Rangifer tarandus, and snow sheep Ovis nivicola, but since then the list has expanded. This is due to the introduction of bison Bison bonasus, Bison bison, muskox Ovibos moschatus, non‐native deer, and feral horses, as well as the northward expansion of wild boar Sus scrofa, roe deer Capreolus capreolus, Capreolus pygargus, and red deer Cervus canadensis. In addition, several southern species temporarily occurred in the north, including tiger Panthera tigris, sika deer Cervus nippon, and yak Bos grunniens. This ongoing enrichment of the boreal fauna is reminiscent to Pleistocene rewilding. However, so far, the abundance of expanding large mammals species remains low. Large‐scale projects on Pleistocene rewilding are labor‐intensive, expensive, and not popular enough to receive support, and therefore their realization is problematic

A field test of R package GPSeqClus: For establishing animal location clusters

Abstract The ability to track animals with Global Positioning System (GPS) collars opened an enormous potential for studying animal movements and behaviour in their natural environment. One such endeavour is to identify clusters of GPS locations as a way to estimate predator kill rate. Clapp et al. (2021) developed an R package (GPSeqClus) to assess a location dataset based on user‐defined parameters to identify clusters and their characteristics. These characteristics can then help to distinguish resting‐site clusters from kill sites of their large (>50 kg) prey. We identified location clusters of an adult male wolf Canis lupus on Ellesmere Island, Nunavut, Canada in July 2009 and tracked him until he died in April 2010. Identifying location clusters was challenging because the collar only obtained two GPS locations per day (12 h apart). In July 2010, we searched 30 of 52 location‐clusters we identified as kill/scavenge sites and found 17 of them as such, given they had muskox Ovibos moschatus or caribou Rangifer tarandus pearyi remains nearby. We also documented five wolf rendezvous sites, two den sites, and the wolf's death site to total 60 location‐clusters in all. We used a two‐step process in testing the R Package GPSeqClus (hereafter GPSeqClus): (1) compare the number of clusters our method discerned with the number identified by the new algorithm, and (2) compare the number of biologically significant clusters (e.g. den sites, kill/feeding sites) we found with the number the new algorithm located. We made these tests with GPSeqClus by varying the search radius, number of days at a site, and minimum number of locations required for a cluster. GPSeqClus compared well to our technique, with the best sub‐algorithm among the 25 we tested only missing three of our identified clusters and yielding six additional clusters. GPSeqClus identified 16 of the 17 confirmed sites of remains, all wolf home sites, and the wolf's carcass site. Identifying clusters using a 500‐m search radius, a 1.5‐day window, and a minimum of two GPS locations per cluster was suitable for a coarse GPS acquisition rate of two locations per day when prey are large, such as muskox or caribou. Given that GPSeqClus performed well with our coarse location dataset, we expect it will also perform even better with a collar acquiring more than two locations per day. Having a field‐tested utility such as GPSeqClus will enhance carnivore predation studies elsewhere.

Muskoxen homogenise soil microbial communities and affect the abundance of methanogens and methanotrophs

Grazing herbivores may affect soil microbial communities indirectly by impacting soil structure and vegetation composition. In high arctic environments, this impact is poorly elucidated, while having potentially wide-reaching effects on the ecosystem.This study examines how a key arctic herbivore, the muskox Ovibos moschatus, affects the soil microbial community in a high arctic fen. Environmental DNA was extracted from soil samples taken from grazed control plots and from muskox exclosures established 5 years prior. We sequenced amplicons of the 16S rRNA gene to provide insight into the microbial communities. We found that in the grazed control plots, microbial communities exhibited high evenness and displayed highly similar overall diversity. In plots where muskoxen had been excluded, microbial diversity was significantly reduced, and had more uneven intra-sample populations and overall lower ecological richness and evenness. We observed that the composition of microbial communities in grazed soils were significantly affected by the presence of muskoxen, as seen by elevated relative abundances of Bacteroides and Firmicutes, two major phyla found in muskox faeces. Furthermore, an increase in relative abundance of bacteria involved in degradation of recalcitrant carbohydrates and cycling of nitrogen was observed in grazed soil. Ungrazed soils displayed increased abundances of bacteria potentially involved in anaerobic oxidation of methane, whereas some methanogens were more abundant in grazed soils. This corroborates a previous finding that methane emissions are higher in arctic fens under muskox grazing. Our results show that the presence of large herbivores stimulates soil microbial diversity and has a homogenizing influence on the inter-species dynamics in soil microbial communities. The findings of this study, thus, improve our understanding of the effect of herbivore grazing on arctic ecosystems and the derived methane cycling.

Apparent Collapse of the Peary Caribou (<i>Rangifer tarandus pearyi</i>) Population on Axel Heiberg Island, Nunavut, Canada


 In spring 2019, we conducted a comprehensive abundance and distribution survey for Peary caribou (Rangifer tarandus pearyi) and muskox (Ovibos moschatus) on Axel Heiberg Island, Nunavut, Canada. Although much of Axel Heiberg Island is rugged and extensively glaciated, areas east of the Princess Margaret mountain range have high productivity given the latitude and have supported relatively large numbers of Peary caribou and muskoxen. This region of the island has been previously identified as a potential High Arctic refugium. The last island-wide survey, in 2007, estimated 4237 muskoxen (95% confidence interval [CI] [3371:5325]) and 2291 Peary caribou (95% CI [1636:3208]); based on our 2019 results, it appears that muskox numbers have been stable on Axel Heiberg Island since then. Using distance sampling and density surface models, we estimated 3772 muskoxen (95% CI [3001:4742]) on Axel Heiberg Island during our 2019 survey. In contrast, Peary caribou, which is listed as an endangered species under the Canadian Species at Risk Act, appear to have declined dramatically from the 2007 estimate. During the 2019 survey, we observed only six Peary caribou and could not generate an island-wide estimate. Abrupt declines in numbers are characteristic of the species and are usually related to poor winter conditions such as dense snowpack or extreme weather events that result in widespread ground-fast icing. However, the limited monitoring information available at the northern extent of Peary caribou range presents major challenges to our understanding of the mechanisms leading to this near total absence of approximately 20% of range-wide Peary caribou numbers.

New data on distribution of musk ox Ovibos moschatus in the Late Pleistocene in the south-east of Western Siberia and the Minusinsk Depression

New data on distribution of musk ox Ovibos moschatus in the Late Pleistocene in the south-east of Western Siberia and the Minusinsk Depression

First occurrence of musk ox Ovibos moschatus in the Late Pleistocene (MIS 3) record from NW Iberia: Paleobiogeographic and paleoenvironmental implications

A remarkable musk ox (Ovibos moschatus) assemblage was recovered at Cowshead Cave (Picos de Europa Mountains, NW Spain). This find is of special paleobiogeographic relevance since it involves the first occurrence of this species in NW Iberia and extends the boundary of its Eurasian distribution range to the SW.Fossils correspond to at least two individuals: one young male about 20 months old, which includes an extraordinarily well-preserved skull, and one subadult of about 38–44 months. The bone deposit, dated to 34.9 ± 0.4 cal ka BP (MIS 3), accumulated in a karst cave that acted as a natural trap, agreeing with the geomorphology and the good preservation of the remains.Considering that musk ox skulls of young individuals are extremely rare in the Pleistocene record, the detailed comparative study of the skull here presented provides new and relevant information. The skull from Cowshead is larger than modern specimens of similar individual age from Greenland; additionally, some remarkable morphological peculiarities in skull and teeth were identified.One metacarpal of the subadult individual was compared to recent and Pleistocene specimens and was among the largest in the entire sample. Significant differences in morphology and size between fossil and recent metacarpals were detected.Teeth microwear analysis suggests a browsing diet based on twigs and leaves at the time of death, which is consistent with a winter diet.The cold and arid environment inferred from the presence of musk ox is consistent with the paleontological record, since cold-adapted mammals occurred at other contemporary assemblages from NW Iberia.

Diversity of muskox Ovibos moschatus (Zimmerman, 1780) (Bovidae, Mammalia) in time and space based on cranial morphometry

ABSTRACT Muskox Ovibos moschatus is a Pleistocene relic, which has survived only in North America and Greenland. During the Pleistocene, it was widely distributed in Eurasia and North America. To evaluate its morphological variability through time and space, we conducted an extensive morphometric study of 217 Praeovibos and Ovibos skull remains. The analyses showed that the skulls grew progressively wider from Praeovibos sp. to the Pleistocene O. moschatus, while from the Pleistocene to the recent O. moschatus, the facial regions of the skull turned narrower and shorter. We also noticed significant geographic differences between the various Pleistocene Ovibos crania. Siberian skulls were usually larger than those from Western and Central Europe. Eastern European muskoxen also exceeded in size those from the other regions of Europe. The large size of Late Pleistocene muskoxen from regions located in more continental climatic regimes was probably associated with the presence of more suitable food resources in steppe-tundra settings. Consistently, radiocarbon-dated records of this species are more numerous in colder periods, when the steppe-tundra was widely spread, and less abundant in warmer periods.

Novel encephalomyelitis-associated astrovirus in a muskox (Ovibos moschatus): a surprise from the archives

BackgroundThe small, single-stranded positive-sense RNA astroviruses are mostly known to be enteric viruses. In recent years, though, different astroviruses were reported in association with neurological disease in various species. In cattle, two distinct neurotropic astrovirus genotype species were described in numerous cases of nonsuppurative encephalomyelitis, with one of these viruses also reported in similar circumstances in several sheep. Here, we retrieved archived formalin-fixed, paraffin-embedded brain tissues of a muskox diagnosed with a comparable disease pattern in 1982 and investigated them for the presence of neurotropic astroviruses with various techniques.ResultsInitially, tissue samples scored positive for both neurotropic astroviruses by immunohistochemistry; however, unexpected results with further immunohistochemical testing, in situ hybridization and qRT-PCR prompted us to submit an RNA extract from the animal’s brain material to next-generation sequencing. We were thus able to obtain the full genome of a novel astrovirus, muskox astrovirus CH18 (MOxAstV-CH18), whose closest relative is an enteric ovine astrovirus. Subsequently, viral RNA could be detected with a specific RT-PCR in the brain of the affected animal, but not in faecal samples from the current muskoxen herd of the animal park where the animal used to be kept.ConclusionsWe identified a novel astrovirus in a historical case of a captive muskox with nonsuppurative encephalomyelitis. Unfortunately, our results and the fact that no material from organs other than of the nervous system was available do not allow any assumption about the epidemiology or pathogenesis of the virus. Still, these findings are yet another piece of evidence that the tropism and species specificity of astroviruses could be more deceptive than generally assumed.

Fossil Ovibos Moschatus (Artiodactyla, Bovidae) from Buryn, with Reference to Muskox Dispersal in the Late Pleistocene of Ukraine

Abstract The skull fragment of muskox Ovibos moschatus (Artiodactyla, Bovidae) obtained from Chasha River bed alluvium near the Buryn (Sumy Region, North-Eastern Ukraine) is described here in detail. It belongs to a young male, and presumably dates back to Late Pleistocene. This new find slightly extends the known Ukrainian range of the species to the east. Taxonomic attribution of extinct muskox and dispersal of Ovibos moschatus within the territory of Ukraine during the Late Pleistocene are also discussed in the paper.

Orf virus infection in Alaskan mountain goats, Dall\u2019s sheep, muskoxen, caribou and Sitka black-tailed deer

BackgroundThe zoonotic Orf virus (ORFV; genus Parapoxvirus, Poxviridae family) occurs worldwide and is transmitted between sheep and goats, wildlife and man. Archived tissue samples from 16 Alaskan wildlife cases, representing mountain goat (Oreamnos americanus, n = 8), Dall’s sheep (Ovis dalli dalli, n = 3), muskox (Ovibos moschatus, n = 3), Sitka black-tailed deer (Odocoileus hemionus sitkensis, n = 1) and caribou (Rangifer tarandus granti, n = 1), were analyzed.ResultsClinical signs and pathology were most severe in mountain goats, affecting most mucocutaneous regions, including palpebrae, nares, lips, anus, prepuce or vulva, as well as coronary bands. The proliferative masses were solid and nodular, covered by dark friable crusts. For Dall’s sheep lambs and juveniles, the gross lesions were similar to those of mountain goats, but not as extensive. The muskoxen displayed ulcerative lesions on the legs. The caribou had two ulcerative lesions on the upper lip, as well as lesions on the distal part of the legs, around the main and dew claws. A large hairless spherical mass, with the characteristics of a fibroma, was sampled from a Sitka black-tailed deer, which did not show proliferative lesions typical of an ORFV infection. Polymerase chain reaction analyses for B2L, GIF, vIL-10 and ATI demonstrated ORFV specific DNA in all cases. Sequences from Dall’s sheep formed a separate cluster, comparable to ORFV from domestic sheep. Sequences from the other species were different from the Dall’s sheep sequences, but almost identical to each other.ConclusionsThis is the first major investigation of parapoxvirus infections in large Alaskan game species, and the first report of parapoxvirus infection in caribou and Sitka black-tailed deer. This study shows that most of the wild ruminant species in Alaska and from most parts of Alaska, can carry and be affected by ORFV. These findings call for attention to transmission of ORFV from wildlife to livestock and to hunters, subsistence harvesters, and wildlife biologists.

Ungulate movement in an extreme seasonal environment: year‐round movement patterns of high‐arctic muskoxen

Detailed knowledge on movement behaviour of free‐ranging muskoxen Ovibos moschatus is currently lacking. Quantifying variation in individual movement and the variables driving such patterns is important to understand how they meet their basic requirements and to inform management. Because muskoxen exist in nutrient‐poor systems with extreme climatic and seasonal variability, individual movement patterns are expected to be largely dependent on environmental conditions and the seasonal variation therein. We analysed high‐resolution location data of 14 adult female muskoxen roaming around Zackenberg in northeast Greenland (74°28′N, 20°34′W). We assessed the relative importance (Akaike variable weights) of multiple extrinsic conditions in explaining variation in hourly speed, turning angles, and activity. We found that time of day, ambient temperature, and land cover types were the most important covariates explaining variation in fine‐scale movement and activity patterns throughout the year. Movement speeds were consistently lower in land cover types with more dense vegetation. Speed of movement was positively correlated with ambient temperature when the days were long, while negatively related with temperature in periods with few or no hours of daylight. Diurnal peaks in movement and activity patterns were observed most of the year (including mid‐winter months with 24‐h darkness), except during high‐summer (24‐h of daylight), when individual movement and activity remained continuously high. The topographic variation (elevation and slope) explained only a small part of the variation in muskox movement patterns in the areas where the muskoxen were observed. Analyses of displacement patterns revealed a mixture of movement behaviours. We conclude that muskoxen in high‐arctic Greenland adopt a largely nomadic movement behaviour, but do so within a rather small geographical area (app. 5000 km2), and that their movement and activity patterns are largely directed at finding suitable foraging patches and avoiding cold‐stress during harsh winter weather.

Long-term patterns of muskox (Ovibos moschatus) demographics in high arctic Greenland

Animal abundance is a key measure in conservation and management and tightly linked to population demographics. Demographic data from remote regions, however, are often scarce. Here, we present long-term (1996–2013) demographics on the muskox Ovibos moschatus population at Zackenberg in northeast Greenland. We examine both the inter- and intra-annual patterns in demographic parameters and relate these to environmental conditions. The sex and age composition of muskox groups changed during the study period, and changes were particularly evident in the increasing versus the decreasing phase of muskox abundance. The seasonal pattern of muskox density and group size was a parallel increase from late winter to autumn, which peaked at high densities (approximately seven individuals per km2) in the autumn. The composition of muskox groups also changed between seasons. Across years, the muskox population dynamics was mainly driven by spring snow cover (an indicator of winter conditions), which primarily impacted the calf and yearling recruitments. This relationship, however, appeared to have a temporary decoupling, which may be attributable to pathogens. Our study provides rare insight into the long-term demographics of a remote ungulate population in relation to drivers of change and thus aids the development of adequate monitoring and management plans for muskoxen in a changing Arctic.

Changes in the Eurasian distribution of the musk ox (Ovibos moschatus) and the extinct bison (Bison priscus) during the last 50 ka BP

A recent update of the PALEOFAUNA database (including new 14C dates) revealed new insights in the changes in the geographical distribution and the (local) extinction of larger mammals in Northern Eurasia during the second part of the Late Pleistocene and the Holocene, a period with dramatic changes in climate. In this paper, we present and discuss the observed changes in the distribution of two herbivore species: the musk ox Ovibos moschatus and the extinct bison Bison priscus, which are the major components of the “mammoth steppe” mammalian assemblage. The decrease of their ranges and their extinction during the Holocene (as a part of the Megafauna extinction in Eurasia) was primarily connected with changes in climate and partly the result of Anthropogenic pressure.

Extinction of large herbivore mammals: Niche characteristics of the musk ox Ovibos moschatus and the reindeer Rangifer tarandus coexisting in isolation

The extinction of large northern herbivores is a puzzle for many biologists. It is long debated whether climate change or human activity was the main factor of the extinction. The survival of the weak trophic competitors should reject the climatic hypothesis. Extant species of Pleistocene communities allow testing this explicitly. Up to date, reindeer and musk ox coexist in the Arctic territory. Their island populations provide a unique natural experiment to assess the role of competition. On Wrangel Island, their population sizes show the opposite trends and the same situation recurs on other Arctic islands--the reindeer population size decreases with the muskoxen population increasing. We have shown that the trends are defined by food-web structure. Niche overlap between species is found to .be considerable and cannot be facilitated by habitat partitioning. The number of plant species in the muskoxen diet was higher than in the reindeer. The exclusive part of the muskoxen diet was higher as well. Food webs in all of the habitat types showed the same relation. However, the changes in herbivores distribution during the Pleistocene demonstrate the opposite pattern. Therefore, the competitive advantage could not save the Palaearctic musk ox, and the extinction seems to be a result of selective overkill. Conclusively, the human activity may be considered as the main factor of the Late Pleistocene herbivore extinctions, and the musk ox reintroducing should be coupled with extensive conservational measures.

Dating of a muskox (Ovibos moschatus) skull fragment from Jämtland, Sweden: Middle Weichselian age

A radiocarbon age determination of a tundra muskox (Ovibos moschatus) skull fragment from Jämtland, central Sweden gave an age of 44 000 ± 1500 14C years BP or c. 46–49 cal. ka, indicating that the species was a member of the Middle Weichselian fauna of Sweden. The age confirms that central Sweden was ice-free during parts of the Middle Weichselian, prior to the last glacial maximum, as shown by previous studies. The region was probably characterised by treeless arctic to subarctic tundra environments.

95. Annual dynamics of body temperature of Musk-ox (Ovibos moschatus) under Yakutia conditions

95. Annual dynamics of body temperature of Musk-ox (Ovibos moschatus) under Yakutia conditions

The impact of founder events and introductions on genetic variation in the muskox Ovibos moschatus in Sweden

The muskox Ovibos moschatus (Zimmerman 1780) is a specialised arctic mammal with a highly fragmented circumpolar distribution, with native populations in Canada and east Greenland and introduced populations in west Greenland, Alaska, Siberia and Eurasia. In 1971, five O. moschatus individuals from an introduced population in Norway migrated to Sweden. After a peak population of 36 individuals in the mid-1980s, the Swedish population now numbers seven individuals, making it vulnerable to both demographic and genetic stochasticity (i.e. inbreeding). Here, we analyse genetic variation among native and introduced populations of O. moschatus to evaluate the genetic effect of sequential founder events in this species. Our results show that genetic variation among native and introduced O. moschatus populations do not conform entirely to the expectations from sequential founder events, most likely because of random processes associated with introduction. In the Swedish population, a calf resulting from the mating of a wild cow and a captive Greenlandic bull contributes significantly to the current genetic variation. Thus, even a single outbreeding event may, at least momentarily, increase the genetic variation and potentially prevent inbreeding depression. Our results should aid the long-term preservation of O. moschatus in Sweden and Europe.

Experiences from 40 years of muskox (Ovibos moschatus) farming in Norway

Experiences from the management of a semi-domesticated herd of muskoxen, mostly on an island outside Tromsø (~70º N; 19º E), over a period of 40 years have been collected, and data on husbandry practices, reproduction, diseases and longevity are presented and discussed.

Microsatellite DNA variability in the populations of muskoxen Ovibos moschatus transplanted into the Russian North

The muskoxen populations introduced to the Taimyr Peninsula and Wrangel Island in 1974 to 1975 were examined for sequence variation at seven microsatellite loci. Donor material originated from the populations of Banks Island (Canada) and Eastern Greenland. Relative to the allele frequencies, both introduced populations demonstrated rather strong deviation from the populations of the native range. At the same time, population allelic structures evidenced that they were closer to the Greenland populations. Estimates of genetic diversity at microsatellite loci (expected heterozygosity and the allele number) in the introduced muskoxen were found to be high for populations originating from a small number of founder individuals. In the immigrants, linkage disequilibrium and deviation of the genotype frequencies from the Hardy-Weinberg proportions were observed, which was mainly caused by the deficit of heterozygotes. The same pattern was also typical of native populations and was explained in terms of specific population structure and demographic processes. The latter were manifested as a periodic decline of the effective population size, resulting in the prevailing influence of genetic drift and inbreeding. The consequences of genetic drift were not as dramatic, as could be expected, which may be explained by a high mutation rate of neutral microsatellite loci and fast growth of the new populations.

Is there a cost of parasites to caribou?

Macroparasites potentially play a significant but often ignored role in the ecology and dynamics of wild ruminant populations. In the Arctic, parasites may impact on host populations by exacerbating the effects of seasonal and limited forage availability on the condition, fecundity and survival of individuals. We studied the effects of abomasal nematode parasites and warble flies, Hypoderma tarandi, on condition and pregnancy of caribou Rangifer tarandus in the Dolphin-Union herd, Nunavut, Canada. By the end of winter, female caribou over 2 years old showed a significant decrease in body weight with increasing nematode burden, and a decrease in back fat depth with increasing warble abundance. These effects were exaggerated in the non-pregnant fraction of the population. High warble larvae burdens were also associated with significantly reduced probability of being pregnant. Our research demonstrates a negative relationship between parasites and caribou condition that may have consequences for their fitness. Additionally, we discuss the possibility that muskox Ovibos moschatus share some parasite species with the caribou and could lead to elevated burdens in the sympatric host. Parasites may have been a contributory factor in a previous winter range-shift of the caribou herd and this may reflect a form of apparent competition between the two ungulate species.