International Polar Bear Day | In the extremely cold land, how do these "white miracles" achieve their dominance?

The structure of polar bear hair is exquisite. It has two layers of hair. The outer layer is thick and long guard hair, like a loyal guard, protecting the polar bear from wind and rain, resisting the harsh environment of the outside world, and preventing rain and snow from wetting the body; the inner layer is dense down, like a warm blanket, tightly wrapping the polar bear's body and locking in every bit of heat.

Polar bears' hair may appear pure white, but each strand is actually transparent and hollow. These tiny hollow structures act like countless small prisms that scatter and reflect sunlight, allowing polar bears to blend perfectly into the white background of ice and snow. When hunting, this natural camouflage allows them to sneak up on their prey without being noticed. For example, when seals are basking on the ice, polar bears use this camouflage to slowly approach until they launch a surprise attack.

The density of polar bear hair is even more amazing. There are about 1,000 hairs per square centimeter of skin. In comparison, the hair density of most ordinary animals is much lower. Such a high density of hair is closely arranged, forming a thick insulation layer, just like putting on a super warm suit for polar bears that they never take off, effectively preventing the loss of body heat.

Polar bear hair has many functions. Insulation is its most important function. The hair is full of air, and air is a poor conductor of heat. This is like a circle of efficient insulation around the body of the polar bear. Even if the outside temperature is as low as minus 50 degrees Celsius, the polar bear can still maintain a normal body temperature of around 37 degrees Celsius and move leisurely on the ice.

Camouflage also gives polar bears an advantage in the competition for survival in the Arctic. In the white world of ice and snow, polar bears' white fur blends in with the environment, allowing them to avoid predators or sneak up on prey without being noticed. Scientists have observed that polar bears use this camouflage to lurk near ice caves, waiting for seals to emerge for air, with a high success rate.

In addition, polar bears' hair has functions such as waterproofing and reducing friction. The waterproof function allows them to quickly shake off water droplets after swimming in the cold sea water and keep their bodies dry and warm; while the smooth structure between the hair reduces friction during movement, making polar bears more agile.

Compared with other Arctic animals, polar bears have obvious advantages in hair. Although the hair of Arctic foxes can also keep warm, it is far less dense and long than that of polar bears; while seal fur focuses mainly on streamlining and waterproofing in water, and its thermal insulation effect is inferior to that of polar bears.

Humans have also gained inspiration from the heat preservation principle of polar bear hair. Scientists have imitated the hollow structure of polar bear hair and developed new types of thermal insulation materials for use in outdoor clothing and aerospace equipment.

Polar bears' hair, with its unique structure and diverse functions, is the key to their survival in the harsh Arctic environment. However, with global warming and the continuous melting of Arctic ice, polar bears' habitats are under serious threat. It is urgent to protect polar bears and their habitats. Only by maintaining a good ecological balance can these Arctic elves continue to roam freely on the ice field, and their magical hair can continue to write the legend of survival. In the remote and cold Arctic, the ice and snow are endless. A polar bear walks on the white ice with steady steps. It is majestic, like the king of this ice and snow world. In this extremely cold place with an average temperature of dozens of degrees below zero, how do polar bears survive? The answer lies in their magical hair.

References

[1] Xiao Ting. Chinese scholars have prepared polar bear hair bionic thermal insulation materials[J]. China Fiber Inspection, 2024, (03): 93.

[2] Bai Hao, Shao Ziyu, Zhou Shaodong, et al. Teaching case of heat transfer model application: modeling and analysis of the thermal insulation effect of polar bear hair[J]. Guangzhou Chemical Industry, 2021, 49(23): 135-138.

[3] Wang Qingli, Xie Huili, He Jihuan. Thermal conductivity of polar bear hair fibers[J]. Wool Textile Technology, 2012, 40(09): 59-64.

[4] Shao Ziyu. Research on mechanical properties of polar bear hair and preparation of bionic fabrics[D]. Zhejiang University, 2021. DOI: 10.27461/d.cnki.gzjdx.2021.002233.