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Animals use their self protection instinct to save themselves from danger. To do this, they adopt their innate mechanisms of self protection from their enemies. In this article, we have selected some of the most sophisticated measures taken by animals, mostly the vulnerable ones to keep themselves safe.

For example, in this case we are taking a pangolin as an animal that can protect itself from danger. A pangolin, for instance, will roll up into a ball like shape for self protection as its behaviour besides it has hard scales as its special characteristics to protect itself.

Different animals, also have different physical characteristics that protect themselves from their enemies. These include:

1. a hard shell
2. thick skin
3. dry, hard scales
4. horns
5. spines
6. sharp claws
7. body shape or colour that matches the surroundings
8. good eyesightandhearing

The bodies of garden snails, clams, crabs and tortoises are covered by a hard shell. The shells help them to protect their enemies. Garden snails and tortoises can also pull their head, legs or their whole bodies inside their shell. Clams protect themselves by closing up their shells.

Porcupines, porcupine fish and starfish have spines on the surface of their body. The spines can injure enemies that go near or attack these animals.

1. Porcupines raise their long, stiff spines as a warning when their enemies go near them.
2. A porcupine fish can inflate its body by drinking a lot of water. This raises the sharp spines on the fish’s body. The spines help to keep the fish’s enemies away.

Some animals have body shapes or colours that match their surroundings. This makes it easier for these animals to hide from their enemies.

1. Leaf insects have green body parts that look like leaves.
2. Sticks insects have a long, thin body that look like a stick or twig. Their body colour is also similar to the colour of twigs.
3. Zebras have black and white stripes on their bodies. This makes it more difficult for their enemies to spot them from a distance.

Centipedes, cobras, wasps and scorpions can defend themselves from their enemies by using their poison.

1. Centipedes and cobras can bite their enemies to weaken or kill them.
2. Wasps and scorpions can sting their enemies to weaken or kill them.

Besides physical characteristics, some animals also behave in special ways of self protection from enemies. These include:

1. changing the colour of fur or skin
2. living in groups
3. pretending to be dead
4. breaking off a body part
5. giving off a bad smell or black ink
6. running or flying away
7. hiding

For example, the artic fox can change the colour of its fur to match the colour of its surrounding. In spring and summer, the artic fox has grey fur. Before the start of autumn and winter, its fur will change to white. By changing the colour of its fur, the artic fox can avoid being detected by its enemies easily.

Chameleon use a technique calledcamouflage for self protection, by changing their skin colour to match the colour of their surroundings, for example, the colour a tree trunk. This ability helps chameleons to hide from their enemies.

Some beetles and millipedes pretend to be dead as a self protection measure when they are attacked or threatened.

Elephants, deer, buffaloes and zebras live and move from place to place in groups (herds). This allows them to defend themselves together when they are in danger. For example, when predator tries to attack the young of the elephants, the adult elephants will form a circle and keep their young in the centre of the circle.

Besides, animals on earth live in many different habitats. Some of these habitats may be very hot or very cold. Animals that live in very hot habitats include camels and hippopotamuses. Animals that live in very cold habitats include whales and polar bears. Such animals have to adapt to the extreme weather in order to survive.

Some animals such as zebras have to adopt self protection measures to protect themselves against both their enemies and extreme weather. Some large animals such as elephants do not have natural enemies. However, they still have to protect themselves from their hot weather in their habitat to stay alive. During a drought, they have to move to new habitats to find water and food.

Only animals that can protect themselves from their enemies and extreme weather will survive in nature. Animals that cannot do so will be easily killed by their enemies or die of heat, cold or hunger. When all animals of the same type die, that type of animals will become extinct.

The greenhouse effect refers to heat trapping action of the atmosphere caused by atmospheric gases and results in the general increase in earth temperature. When the sun’s thermal radiation is able to pass through the atmosphere due to its short wavelength. However, upon reaching the earth surface, the radiation is reflected back into the atmosphere with a long wavelength and this time, the atmosphere acts as a ‘heat trap’ which absorb the re-radiated heat. This happens because some gases (namely water vapour, carbon dioxide and methane) absorb energy strongly at certain wavelengths in the infrared radiation.

The presence of water vapour, carbon dioxide (CO₂) and other gases in the air has served the planet well. The‘trapping’ of heat by the atmosphere has kept the Earth warm. Without the greenhouse effect, the earth’s surface would be about 25°C cooler than it is today. However, the emission of extra carbon dioxide from the burning fuels (petrol, coal, etc.) may be adding to this effect and causing what is called ‘global warming’

The‘greenhouse gases’that produce this warming include water vapour, carbon dioxide, methane, the oxides of nitrogen and CFCs (chlorofluorocarbons). These gases absorb heat from the Sun that is reflected from the Earth’s surface. They prevent this heat from being re-radiated back into space. So the Earth’s surface becomes warmer.

The levels of carbon dioxide released into the atmosphere are very high (about 5000 million tonnes per year). Large-scale deforestation, particularly of the tropical rainforests, to provide land for agriculture, also increases the level of carbon dioxide in the air because it removes trees j which absorb the gas for photosynthesis.

The effects of global warming are complex. The polar ice-caps would begin to melt as the temperature rose. The increase in sea level would threaten low-lying lands. Extensive climate change I is possible but is difficult to predict. In some regions the effects may be good; but others may suffer long droughts. There could be major shifts in desert and fertile regions. Tropical storms could | increase in their intensity.

There is evidence, from dying corals to an increase in warm-water fish in the North Sea, to show that global warming is taking place. Whether this is due to increased carbon dioxide levels remains to be proved. Certainly the concentration of CO₂in the Earth’s atmosphere has increased over the last century (in 1850 it was 0.027%, and in 1993 it was 0.036%).

Ozone layer depletion

A protective layer of ozone in the stratosphere prevents harmful ultra-violet radiation reaching the Earth’s surface. CFCs and other halogen compounds are thought to cause the damage. International agreement has been reached on restricting the use of these compounds (the Montreal Protocol). If the situation were allowed to grow worse, exposure to higher levels of ultraviolet radiation could cause more cases of skin cancer in humans, and cause damage to crops.

There are various types of pollution that occur over smaller, local areas. These usually occur in large cities, where there is heavy use of motor cars. These forms of pollution are:

• photochemical smog,
• high levels of carbon monoxide, and
• high levels of lead compounds.

Photochemical smogis formed in regions where there is a large amount of traffic. It was first identified in Los Angeles, and forms only under certain conditions. Severe photochemical smog often occurs in cities located in valleys, or surrounded by hills or mountains. On sunny, windless days, oxides of nitrogen are trapped by the hills in air that is close to the ground. A complicated series of reactions takes place and ground-level ozone is one of the products. In these circumstances ozone is harmful, particularly for asthma sufferers.

Carbon monoxideis the most common air pollutant in the industrialised world. It is produced when hydrocarbon fuels are incompletely burnt. Carbon monoxide is poisonous at levels of only 0.1%. Oxygen is very important to living things.

In our bodies it is carried round the body attached to haemoglobin in our red blood cells. Carbon monoxide is attracted to haemoglobin over 200 times more strongly than oxygen. In the blood, carbon monoxide prevents haemoglobin from carrying oxygen. This leads to dizziness and headaches. Prolonged exposure to carbon monoxide causes death.

Lead compoundsare the most toxic heavy-metal pollutants in the air. Lead compounds form part of the ‘urban dust’ that forms in a city atmosphere.

People living next to busy roads can have high levels of lead in their blood. This has been linked with nervous disorders and with learning disabilities in children. The increased moves to use unleaded petrol are reducing this health hazard.