Lakhasly

1 Invasive species are plants and animals which arrive in an area where they are not native, usually due to human activity. For example, a species of shellfish might attach itself to the outside of a ship travelling between countries and enter a new environment in this way. Invasive species are often able to grow quickly in their new homes because they have no natural enemies. As a result, they may replace or damage native plants and animals which live in the same environment. One example is the case of grey and red squirrels in the UK.

2 Red squirrels used to be a common sight in British forests and countryside. Then, in the 1870s, the grey squirrel was introduced from North America because rich people thought the squirrels looked fashionable in the gardens of their large homes. Today, only about 140,000 red squirrels remain, mostly in Scotland. In contrast, grey squirrels are now extremely common and seen as major pests due to the damage they cause to plants and houses. While red squirrels are protected, grey squirrels can be legally trapped and destroyed.

3 At first sight, the two species of squirrel are similar. They both have a long tail, which helps them balance when jumping from tree to tree, and the same large eyes, small ears, and powerful back legs. In contrast, the two types of squirrel are different in body size and weight. The red squirrel has a typical head-and-body length of approximately 19 to 23 cm, a tail length of 15 to 20 cm, and a body weight of 250 to 340 g. The grey squirrel is larger than the red squirrel. The head and body measure between 23 and 30 cm, and the tail is between 19 and 25 cm long. Adult grey squirrels are also heavier, weighing between 400 and 600 g. This size allows them to store more fat and helps them to survive hard winters, which could be fatal to their smaller cousins.

5 Three more differences explain why red squirrels have lost out in the competition with grey squirrels. First, red squirrels live high up in the trees, whereas grey squirrels spend more of their time on the ground. This means that any loss of forest habitat greatly affects the red squirrel population. Another reason is that grey squirrels are more intelligent and can adapt to new situations more easily than red squirrels. For example, they can survive in an urban environment because of their ability to use food provided by humans. A third problem for the red squirrel is disease. Both squirrels carry parapoxvirus. The virus does not seem to affect grey squirrels, but it is fatal to reds.

6 In conclusion, there does not seem to be much that scientists can do to help red squirrels survive in Britain. Some politicians support destroying populations of grey squirrels, but many British people would contend that this is cruel. Red squirrels have been successfully reintroduced from other countries, and they could be protected in places where there are no grey squirrels, such as the Isle of Wight. However, some people question whether Britain should protect red squirrels at all. Worldwide, they are not an endangered species. Considering the evidence, saving the red squirrel may be a waste of British government money. Government conservation funding should instead be spent on other endangered animals.