The animal with the longest hair on Earth is the musk ox, also known as the Arctic musk ox, a mammal belonging to the order Artiodactyla, family Bovidae, and genus *Musk ox*. Musk oxen have long, thick, dark brown hair, with a mane extending from their neck and back to their shoulders. This mane is over 30 centimeters long, sometimes reaching 60 centimeters, and is slightly curly, hanging down like a cape. The hair consists of two layers: beneath the long hair is a thick layer of down called guard hairs, which is both tough and soft, providing protection from cold and moisture; the upper guard hairs protect against rain and snow and are durable. The back of the body is covered with light-colored, saddle-shaped hair. The white area becomes more pronounced with age.
The scientific name of the musk ox means "sheep-cattle," indicating that it is a transitional animal between cattle and sheep. It closely resembles a cow in appearance, with cow-like horns and many other bovine features, but its tail is very short, hidden beneath long hair. Its limbs are short and strong, with broad, wide hooves covered in white hair, allowing it to walk on ice and snow without slipping. Interestingly, its left and right hooves are not symmetrical. Both males and females have horns, which are flat and thick at the base, splitting in the middle and growing outwards along the skull. The horns initially curve downwards before pointing upwards. They are about 60 centimeters long, with the longest recorded at 70.5 centimeters; the female horns are much shorter.
Musk oxen are a species endemic to the Arctic tundra. In summer, they tend to seek shelter in damp lowlands, such as river valleys and lakeshores; in winter, they move to higher slopes, plateaus, and areas with deep snow accumulation for easier foraging. They are relatively resistant to hunger and thirst, and their thick, dense fur provides protection against the Arctic's frigid temperatures of -40 to 50 degrees Celsius. The musk ox's thick, dense fur is sufficient to resist any cold and moisture, while the outer layer of coarse, long hair is suitable for protecting against rain, snow, and strong winds. Therefore, musk oxen are extremely cold-resistant animals, but they are very sensitive to heat.
At the northernmost tip of the Earth's ungulates: In the colder climates of high latitudes, fur is essential for animal survival. No ungulate lives further north than the musk ox—found in the Canadian Arctic at 83°N and Greenland. Musk oxen have a double coat of fur that can withstand temperatures as low as -40°C. It is said that the undercoat shed by the musk ox during its annual molting season is eight times warmer than sheep's wool, while its outer protective hair is among the longest in the animal kingdom, reaching up to 60 centimeters in length. (Guinness World Records)
