Contents
Environmental science incorporates Biology Topics to understand environmental issues.
A brief history of the polar regions
The polar regions of the earth have an extremely cold climate. The polar regions are covered with ice and snow, and it is extremely cold for most part of the year. For six months, the sun does not set at the poles while for the next six months, the sun does not rise (above the horizon). During winter in polar regions, the temperature can be as low as, -37°C (minus 37°C). The animals living in the polar regions have adapted to the extremely cold climate by having some special features such as white colour, thick layer of fur, thick skin, a layer of fat under the skin, strong sense of smell, and big feet (big paws) for walking on soft snow and swimming, etc. The two animals which live in polar regions are polar bears and penguins. Polar bears live in north pole region whereas penguins live in the south pole region
of the earth. We will now understand how animals of the polar regions have adapted to live in the severely cold climate by taking the examples of polar bear and penguins.
Adaptations in Polar Bear
The polar bear is a large, white bear which lives in north polar regions of the earth (see Figure). The polar bear feeds mainly on fish and seal (seal is an aquatic mammal). The polar bear lives in extremely cold climate of polar regions due to the following adaptations :
1. Polar bear has white colour which matches with its surroundings. Due to white colour, polar bear is not visible easily in the snowy white background and hence its prey is unable to see it. This adaptation (of white colour) helps the polar bear to catch its prey. The white colour of polar bear also protects it from its predators (who kill and eat it) because it mixes well with the snowy white surroundings due to which the predators cannot see it easily.
2. Polar bear has two thick layers of fur on its body. This fur protects the polar bear from extreme cold by preventing the loss of heat from its body. Thus, the two thick layers of fur keep the polar bear warm in extremely cold climate (by keeping its body heat in). The polar bear has also fur on its feet and toes. This protects it from cold when it walks on snow and ice.
3. Polar bear has a thick layer of fat under its skin. This layer of fat insulates the body of polar bear against heat loss and keeps it warm in cold climate. Thus, the thick layer of fat also protects the polar bear from extreme cold.
4. Polar bear has a rounded body and small ears to keep the body surface area to a minimum (compared to the body weight). This reduces the heat loss from the body of polar bear.
5. Polar bear has big feet (or big paws) to spread the weight of its body on snow which prevent it from sinking into snow and make it walk on snow easily. Polar bear has long, curved and sharp claws which help it to walk and run on slippery ice.
6. Polar bear is a good swimmer. The big feet (or big paws) help the polar bear to swim well. Being a fast swimmer helps the polar bear to catch its prey (like seal) in water very easily. While swimming under water, polar bear can close its nostrils and remain under water for long durations.
7. Polar bear has a very strong sense of smell. The very strong sense of smell helps the polar bear in locating and catching its prey for food.
Adaptations in Penguins
Penguin is an animal which lives in extremely cold south polar region of the earth. Penguin is a sea-bird which cannot fly (see Figure 8). Penguins hunt for fish which they eat as food. Penguins can live in the extremely cold climate of the polar region due to the following adaptations :
- Penguin is black and white in colour but still it merges well with the white background of ice and snow.
- Penguin has thick skin and a layer of fat below its skin which protect it from extreme cold.
- Penguins live together in large numbers. Penguins huddle together to keep themselves warm.
- Penguin has streamlined body, flipper-like wings and webbed feet which make it a good swimmer. Being a good swimmer helps penguin in catching fish as prey.
In addition to polar bears and penguins, some other animals which live in polar regions are Musk oxen, Reindeers, Arctic foxes, Seals, Whales, many kinds of Fish and Birds.