Those who believes that the fund that goes toward the zoos can be used more efficiently when spent for other purposes might say that zoos do not have any useful purpose. However, I have a contrary opinion. There are two major aspects: saving endangered animals and offering a place for people and help them learn about animals.
To begin with, when it comes to saving endangered animals are concerned, zoos have attributed a lot toward it. It might be true that some animals that are not social and tend to migrate over a large area may hard time adjust to the zoo environment. However, many zoologists and experts are trying their very best to try to make the zoo environment as much similar to natural environment. In addition, the most prominent achievement that the zoo performed is helping endangered animals to prosper such as mountain tigers, polar bears and a variety of birds. If it had not been zoos and govenments' care, those animals might not have survived in this polluted and dog-eat-dog world. For example, governments nominate endangered speices every year and put them in the zoos' care because if they do not plan any method to prevent their decimation, endangered animals have almost no chance of surviving due to the many factors, especially harms resulted from human activities. U.S government have banned a wild wolf hunt for many decades now because they found out that wild wolves attribute much to the natural environment and animals' food chain. Due to the passion of the government and the zoo, wild wolf are not endangered animals anymore.
Moreover, from offering a place to relax for families and friends to teaching them about animals and natural environments, there is nothing better than zoos. As society is getting more industrialized and developed, natural environment and places for people to visit for rest purpose have been destroyed. Furthurmore, today's children do not know how some animals look like because they have not seen them in direct. For example, I know how dotted frogs and grass hoppers look like for I used to go to countryside with my family everysummer to catch them and we released most of them at the end of the day, but keep few of them to cook and eat. However, thesedays, children do not know simple because they do not have chance to look at them in everyday life. Those animals and insects are dying off due to the pollution coming from factories and human activities. In this case, children can visit zoos occassionally to look at animals personally and find out how they look like. It is very critical because having this kind of experience helps them boost their imagine and knowledge. What is more is that people can go there together and enjoy great nature and take a rest. It is like catching two birds at the same time.
In conclusion, although it seems that zoos do not play a pivotal role in our society, there are certain things we get from them as a grant. We just do not realize yet. I am sure, the more time goes by the more we feel the importance of zoos.