Are our zoos cruel to wild animals?

Zoos are places that often visited by the people for recreation, moreover for the family who has child. They can find many kinds of animal, without going to the wild forest. Zoos can make the visitors happy, but it might not be the same condition as the wild animal's feeling. I trust that zoos are cruel to the faunas.
Numeruous people think that zoos are good for the wild animals. Keeping animals in the zoos can save the animals from extinction than let them free in their habitat. In their wild habitat, the animal might be killed by their enemies. If they live in the zoo, they could not be killed by their predators because they live in each cage.
In addition, they also think that not all of the zoo are cruel to the wild animal because some of them have standart operational procedures how to protect animal in the zoos, for example is Safari Park Zoos, the biggest zoos in Indonesia.
On the other hand, there are some reasons that can explain why zoos are cruel to the animals. First of all, zoos are not condusive for wild animal's life. They should live in their free habitat. They could feel bored with the limited place that is available in the zoo. Also they cannot interact with the other animals. It can make them feel depressed. If the faunas feel uncomfortable with their habitat, they cannot reproduce well.
So, their offspring will be stopped and the wild animals will be extinct. Except that, the zookeepers also make some mistakes. The zookeepers usually does not take care of the animals. They does not give the suitable food for the animals, does not keep the animals clean, and does not give the good treatment for the animals which are getting sick. The zookeeper sometimes exploitate the animals for their commercial aims. They do not care with their condition.
Perhaps the wild animal is already tired, but the zookeeper still force them to entertain the visitors. The examples are elephant and dolphin which work hard for entertainment events in the zoo.
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