Roughly 170,000 muskoxen remain on Earth, scattered across the Arctic regions of North America, Greenland, and a handful of introduced populations in Scandinavia and Russia.1PubMed Central. Muskox status, recent variation, and uncertain future That number sounds reassuring for a species that was nearly hunted to extinction a century ago, but the global figure hides some troubling details. Six populations are in decline, and the biggest concerns are things most people have never associated with a shaggy Arctic bovid: rain-on-snow events, emerging bacterial diseases, and parasites creeping northward with a warming climate.
Where Muskoxen Live Today
The vast majority of the world’s muskoxen live in Canada and Greenland. Canada’s Arctic Archipelago and mainland tundra hold the largest share, with Banks Island, Victoria Island, and parts of the Northwest Territories historically supporting dense herds. Greenland, particularly the northeast, hosts the next largest concentration. Smaller introduced populations exist in Alaska (reintroduced after being extirpated in the 1800s), Norway, Sweden, and parts of Siberia. These reintroduced herds tend to be small and more closely managed.
Two subspecies are recognized based on physical differences and where they live. The barren-ground muskox occupies mainland Canada, while the white-faced muskox is found across the Arctic islands and Greenland.2Canadian Journal of Zoology. Intraspecific variation in mitochondrial DNA of muskoxen, based on control-region sequences Genetic work has confirmed that the split between the two traces back about 21,000 years, when ice sheets during the last glacial maximum isolated muskox groups in separate refugia across northern North America.3Current Biology. The Muskox Lost a Substantial Part of Its Genetic Diversity on Its Long Road to Greenland The white-faced subspecies ended up colonizing Greenland through a long eastward trek that cost it a substantial portion of its genetic diversity along the way.
Why the Global Number Is Misleading
Saying “170,000” gives the impression of a stable species, and for some herds that is true. But six muskox populations are declining, and as recently as the early 2000s, one of those declining populations was the single largest in the world, accounting for roughly 41 percent of today’s total global count.1PubMed Central. Muskox status, recent variation, and uncertain future That population, centered on Banks Island and neighboring areas in the western Canadian Arctic, crashed for reasons that are still being sorted out but almost certainly involve climate-related events layered on top of disease.
The Banks Island crash is the most dramatic example. In 2003, a rain-on-snow event on the island led to the starvation of roughly 20,000 muskoxen.4National Snow and Ice Data Center. Arctic Rain On Snow Study – Section: ROS Impacts Rain-on-snow events happen when warm air moves in during winter, brings rain that falls on existing snowpack, and then refreezes into a layer of ice. Muskoxen survive winter by pawing through snow to reach grasses, sedges, and willows beneath. When an ice crust seals the ground, the animals simply cannot reach their food. A single prolonged event can starve thousands of animals across a wide area in a matter of weeks.
This kind of catastrophic loss matters more for muskoxen than it would for a species with a faster reproductive rate. Muskox cows typically produce one calf per year at most, and not every year. Recovery from a mass die-off is slow, and if another bad event hits before the population has bounced back, the decline compounds.
Climate Change Is Rewriting the Threat Landscape
Rain-on-snow events are not new, but they are becoming more frequent and more severe as Arctic temperatures rise. Warmer winters bring more episodes of above-freezing temperatures, and the Arctic is warming several times faster than the global average. For an animal whose entire survival strategy depends on being able to dig through soft snow, an increase in ice-crusting events is an existential problem.
Warming is also reshaping the parasite environment. Two lungworm species that infect muskoxen have expanded their range significantly northward across the Canadian Arctic Archipelago over the past few decades. Field surveys and climate-driven models show a substantial northward shift of both parasites’ range edges, along with increased abundance across the areas they have colonized, with the expansion closely tracking the spatial spread of warm enough conditions for the parasites to develop.5PubMed Central. Range expansion of muskox lungworms track rapid arctic warming: implications for geographic colonization under climate forcing In earlier decades, cold temperatures kept parasite development cycles too slow to complete in a single season. As summers lengthen and warm up, the parasites can finish their life cycles faster and spread into areas where muskoxen previously had little exposure to them.6PubMed Central. Global warming is changing the dynamics of Arctic host-parasite systems Muskoxen in newly colonized areas may lack immune experience with these parasites, making the health consequences worse than in populations that have dealt with lungworms for generations.
Bacterial Disease and Mass Mortality
On top of weather and parasites, muskoxen face a bacterial threat that has emerged as one of the most alarming developments in Arctic wildlife health. A specific strain of the bacterium Erysipelothrix rhusiopathiae, known informally as the “Arctic clone,” has been linked to at least three independent mass mortality events in muskoxen in the Canadian high Arctic, including a multi-year die-off on Ellesmere and Axel Heiberg Islands.7Scientific Reports. Erysipelothrix rhusiopathiae clone reemergence in association with a multi-year mass mortality event in high Arctic muskoxen (Ovibos moschatus) The disease can kill quickly and spread through herds that gather closely together, which muskoxen do naturally as a defense against predators.
Modeling work on this bacterium suggests that the picture is more complicated than a simple muskox-to-muskox transmission chain. Alternative hosts like Arctic foxes may help sustain the bacterium in the environment even when muskox numbers drop, and environmental sources like contaminated carcasses and feces can keep the infection circulating. Models predict that disease-driven mortality could cause strong population declines, and the involvement of alternative hosts could accelerate those declines by decoupling transmission from muskox density.8Ecological Modelling. Models reveal the importance of alternative hosts and environmental transmission for emergence of bacterial disease in muskoxen in the Arctic In other words, even as muskox numbers drop, the disease does not necessarily fade away because foxes and the environment keep it going.
For remote high Arctic populations, veterinary intervention is essentially impossible. These are some of the most inaccessible places on Earth, and the herds are widely dispersed. Monitoring itself is difficult, so die-offs can go undetected for a season or more before anyone realizes a population has crashed.
Genetic Poverty in a Surviving Species
Muskoxen carry a genetic legacy of repeated population bottlenecks. The species was squeezed through tight spots during and after the last ice age, and again during the period of intensive hunting in the 19th and early 20th centuries. The white-faced subspecies in particular holds the lowest genome-wide genetic diversity ever recorded in a hoofed mammal.9PubMed. Population genomics of the muskox’ resilience in the near absence of genetic variation
Surprisingly, though, researchers have found no clear evidence of inbreeding depression in native muskox populations. The leading explanation is that the species’ long, gradual declines over thousands of years gave natural selection time to purge the most harmful genetic mutations. When a population shrinks slowly, individuals carrying strongly damaging gene variants are more likely to express those variants and fail to reproduce, effectively cleaning the gene pool of its worst liabilities. A sudden crash, by contrast, can randomly eliminate healthy and unhealthy animals alike, leaving damaging variants intact by sheer chance.
This is an unusual situation in conservation biology. Most species with extremely low genetic diversity are considered fragile precisely because harmful genes tend to accumulate. Muskoxen appear to have sidestepped that trap through the specific tempo of their historical declines. Whether this resilience will hold under the novel pressures of rapid climate change and emerging disease is an open question. Low diversity still means the species has a limited toolkit for adapting to new pathogens or environmental conditions, even if it has purged the worst inherited problems.
What They Eat and How Snow Limits Them
Muskoxen are not picky eaters, but their diet shifts dramatically with the seasons. In summer, they graze on energy-rich grasses and sedges in wetter, more productive lowland habitats. As winter sets in and most of the ground cover becomes inaccessible, they shift to willows growing on windswept ridges and slopes where snow is thinner or blown away entirely. During the coldest months, muskoxen rely heavily on body fat reserves built up over summer, supplemented by whatever forage they can reach.10PubMed Central. Show Me Your Rump Hair and I Will Tell You What You Ate – The Dietary History of Muskoxen (Ovibos moschatus) Revealed by Sequential Stable Isotope Analysis of Guard Hairs
The critical detail is their snow depth threshold, which sits at only about 23 centimeters. Beyond that depth, muskoxen have great difficulty digging down to the vegetation beneath. This is remarkably shallow compared to caribou, which can manage deeper snow. It means muskoxen are tightly constrained in where they can spend winter: they need areas that are either naturally low-snow or regularly scoured by wind. When unusual snowfall buries even those windswept areas, or when rain-on-snow events create ice layers at any depth, the animals have almost no fallback options.
This dietary inflexibility is part of what makes the species so vulnerable to the climate changes described earlier. A slightly snowier winter, a single poorly timed thaw-freeze cycle, or a shift in wind patterns that fails to clear the usual ridges can push a herd past its survival margin. The animals are exquisitely adapted to a very specific set of Arctic conditions, and those conditions are becoming less reliable.
How Muskoxen Shape the Tundra
Muskoxen are not just passengers in Arctic ecosystems. Their grazing visibly shapes the landscape. In southwest Greenland, for example, researchers studying shrub expansion found that shrub cover increased most in areas without muskox grazing. Where muskoxen were present, they kept willows and other shrubs in check.11Arctic, Antarctic, and Alpine Research. Shrub Expansion in SW Greenland Under Modest Regional Warming: Disentangling Effects of Human Disturbance and Grazing Arctic shrub expansion is a major ecological concern because taller shrubs trap snow, darken the land surface, and alter local temperatures, creating feedback loops that accelerate warming. By browsing on willows, muskoxen act as a brake on this process.
A common concern when muskoxen are introduced or reintroduced into areas that also support caribou is whether the two species will compete for food and space. Research from northern Quebec, where muskoxen were introduced into caribou range, found that overlap between the two species was low. Their ranges intersected mainly during caribou migration seasons, and even in shared areas, the animals selected different habitats: muskoxen favored shrub-dominated coastal zones while caribou used rockier tundra. Their diets showed some overlap at the plant family level, with both eating shrubs, but co-occurrence remained limited at broad spatial scales.12The Journal of Wildlife Management. Investigating potential for competition between migratory caribou and introduced muskoxen The evidence so far suggests the two species can coexist without major competitive costs, though this may vary by region.
Harvesting, Qiviut, and Community Management
Muskoxen hold deep cultural and economic importance for Indigenous communities across the Arctic. They are hunted for meat, and their underwool, called qiviut, is one of the most prized natural fibers in the world. Qiviut is extremely fine, warmer than sheep’s wool by weight, and does not shrink when wet. A small industry built around qiviut has existed in Alaska since the 1960s, when muskoxen were first farmed specifically for fiber production. Feasibility analysis of qiviut farming has shown that enterprises can be economically viable, but only when the raw fiber is processed into value-added products like yarn rather than sold as raw material.13Arctic. Farming Muskoxen for Qiviut in Alaska: A Feasibility Study Selling raw qiviut alone was not projected to break even. Muskoxen have also been kept in semi-domesticated herds in Norway for decades, providing researchers with long-term data on husbandry, reproduction, and disease under managed conditions.14Rangifer. Experiences from 40 years of muskox (Ovibos moschatus) farming in Norway
Wild harvest management is a different challenge. In Greenland, some muskox herds are managed primarily by local communities rather than centralized wildlife agencies. One collaborative project developed a user-friendly harvest calculator that combined local ecological knowledge with demographic modeling, allowing community members to test different harvest scenarios and see projected outcomes for their herds. When the tool suggested that the harvest rate of bulls was too high and driving a decline, the community used the findings to request a revised quota from the government, which was approved immediately.15Conservation Science and Practice. Using local ecological knowledge as evidence to guide management: A community‐led harvest calculator for muskoxen in Greenland This kind of approach matters because muskox populations in Greenland are spread across enormous, sparsely populated areas where formal wildlife surveys are expensive and infrequent. Community members who live alongside the herds often have the most current information about herd condition, calf survival, and bull ratios.
Why the Future Is Genuinely Uncertain
Muskoxen survived the ice ages, the collapse of the megafauna around them, and near-extermination by commercial hunters. Their current numbers represent a real recovery success story, particularly in areas like Alaska and parts of Greenland where reintroduction programs have established self-sustaining herds. But the threats they face now are qualitatively different from anything in their recent evolutionary past. Rain-on-snow events, northward-expanding parasites, and emerging bacterial diseases are all tied to a changing climate, and they interact with each other in ways that can compound. A population weakened by a hard winter may be more susceptible to disease. A herd depleted by disease may be less able to recover from a subsequent weather event.
The species’ low genetic diversity adds another layer of concern. While muskoxen have historically managed to avoid inbreeding depression, their limited genetic toolkit means they have fewer options for evolving resistance to new pathogens or adapting to shifting environmental conditions. The populations most at risk are those in the high Arctic islands, where small herd sizes, extreme remoteness, and rapid environmental change converge. Some of these herds number only in the hundreds, and a single bad year could reduce them to levels where recovery becomes uncertain.
Monitoring remains one of the biggest practical challenges. Aerial surveys of remote Arctic terrain are expensive and logistically difficult, and they can only happen during narrow weather windows. Many population estimates carry wide uncertainty margins, and trends can only be detected over multiple survey cycles spaced years apart. By the time a decline is confirmed, it may already be severe. The 170,000 figure represents the best current estimate, but researchers who study muskoxen tend to emphasize the uncertainty around that number and the uneven trajectory of individual herds more than the reassuring headline total.1PubMed Central. Muskox status, recent variation, and uncertain future
For the herds that are stable or growing, the outlook is more encouraging. Introduced populations in places like Quebec and Scandinavia, though small, provide a kind of insurance against catastrophic loss in the core range. Community-based management in Greenland shows that local stewardship can respond quickly to changing conditions. And the species’ demonstrated ability to persist with extraordinarily low genetic variation suggests a toughness that defies conventional conservation expectations. Whether that toughness will be enough for what the Arctic has in store over the coming decades is the question no one can confidently answer yet.