The Arctic fox (Vulpes lagopus) belongs to the family Canidae and is one of the most widely distributed mammals of the high Arctic. It inhabits tundra, coastal pack‑ice, and sub‑arctic islands across North America, Europe, and Asia, ranging from the Canadian Arctic Archipelago to the Siberian coast and the northernmost parts of Scandinavia. Adapted to extreme cold, its dense, multi‑layered fur changes colour seasonally—white in winter for camouflage on snow, and brown or grey in summer to blend with the rocky tundra. The species exhibits a compact body, short muzzle, and a bushy tail that often curls over its back, providing additional insulation. Arctic foxes are opportunistic predators and scavengers, capable of surviving long periods without food by reducing their metabolic rate. Although classified as Least Concern by the IUCN, some isolated populations are declining due to climate change, reduced sea‑ice, and human activities. Conservation measures focus on monitoring population trends, protecting breeding habitats, and mitigating indirect impacts from commercial fisheries and oil exploration.

Arctic foxes are primarily solitary hunters but form monogamous pairs during the breeding season. Outside of reproduction, individuals maintain overlapping home ranges that can span 10–30 km², with males typically holding larger territories that encompass several female ranges. They are crepuscular to nocturnal, increasing activity during twilight hours when prey such as lemmings, voles, and ptarmigan are most active. Social communication relies on a repertoire of vocalizations—high‑pitched barks, whines, and growls—used to signal alarm, maintain pair bonds, and coordinate parental care. Scent marking with urine and anal gland secretions delineates territory boundaries. In winter, Arctic foxes may cache surplus food in shallow pits, a behavior that enhances survival during periods of scarcity. Their thick fur and ability to lower body temperature allow them to endure temperatures as low as –50 °C, while seasonal fur molt reduces heat loss and conserves energy.

The Arctic fox is an opportunistic omnivore with a diet dominated by carnivorous prey. Primary food sources include lemmings (Dicrostonyx spp.) and voles, which can constitute up to 70 % of intake during peak abundance years. When small mammals are scarce, the fox shifts to birds (ptarmigan, gulls), eggs, fish, and carrion, including seal and whale carcasses left by polar bears. In coastal areas, they exploit marine resources such as fish and crustaceans. Seasonal variation drives dietary flexibility; during the summer, they also consume berries, seaweed, and insects. An adult Arctic fox requires roughly 300–500 g of food per day, but can survive prolonged fasting by reducing metabolic rate and relying on fat reserves stored in its thick fur and subcutaneous tissue. Hunting strategies include stalking, rapid short‑bursts of pursuit, and scavenging from predator kills. Food caching in snow pits is common, allowing the fox to retrieve frozen prey when fresh food is unavailable.

Arctic foxes reach sexual maturity at 10–11 months for females and 12–14 months for males. Breeding commences in early spring (March–April) when snow begins to melt, and pairs often reunite with the same mate for multiple seasons. After a gestation period of 51–53 days, the female gives birth to a litter of 5–14 kits, with an average litter size of 7 in optimal conditions. Litter size correlates strongly with prey abundance; in years of lemming peaks, litters can exceed 12 kits. The kits are born blind and fur‑less, weighing about 120 g each. Both parents participate in rearing: the female nurses and guards the den, while the male provides food, often traveling up to 30 km to locate prey. Kits are weaned at 6–8 weeks and begin to accompany parents on foraging trips by 10 weeks. Juveniles attain independence at 4–5 months, though they may remain within the parental territory for the remainder of the year.

The IUCN classifies the Arctic fox as Least Concern globally, yet several regional populations are threatened. Climate change is the most significant long‑term threat, as warming temperatures reduce sea‑ice extent, alter tundra vegetation, and cause declines in lemming cycles, the fox’s primary prey. Reduced sea‑ice also limits access to coastal carrion sources. Increased human activity—oil and gas exploration, shipping routes, and tourism—disturbs breeding habitats and raises the risk of oil spills, which can be lethal to pups. In some parts of Scandinavia, the introduced red fox (Vulpes vulpes) competes for food and preys on Arctic fox kits, contributing to local declines. Population estimates suggest a global total of 1–2 million individuals, but numbers have dropped by up to 30 % in certain sub‑populations over the past two decades. Conservation actions include monitoring lemming cycles, protecting denning sites, regulating industrial development in key habitats, and managing red‑fox incursions through targeted control programs.

• Arctic foxes can lower their metabolic rate by up to 40 % during extreme cold, conserving energy.
• Their fur is the warmest of any animal found in the Arctic, providing up to 50 % insulation.
• In years of lemming abundance, Arctic foxes can produce litters of up to 14 kits, one of the largest litter sizes among mammals.
• They have a remarkable sense of smell, able to locate buried prey under up to 30 cm of snow.
• Arctic foxes have been observed using tools, such as moving stones to uncover hidden food sources.