For companionship - many people keep pets, providing them with the chance to give and receive affection. Pets are usually treated well and are often seen as part of the family.
For help - some animals are used in assisting people, such as guide dogs for the blind or dogs that can help children and adults with other kinds of disabilities. Some charities take animals into nursing homes or homes for the elderly, to aid the wellbeing of residents.
For work - animals can be used to carry goods or people. Some, eg horses, pull equipment, while elephants are used in some countries for logging.
For sport - some people keep animals for sport, eg greyhound or horse racing. They believe that they are giving animals tasks in sport which they enjoy and which will not harm them. Others use animals in sports such as hunting and bullfighting. Many people believe that these kinds of sports lead to the mistreatment of animals.
For food - many people eat meat and other animal products and some animals are specially bred to be eaten. Many people are concerned about animals in factory farms where the animals' lives are restricted and conditions may be poor.
For fashion accessories or leisure - some people enjoy having things made from animals, eg animal skin handbags or chess sets made of ivory. Laws have been passed to protect animals which may be killed only for their ivory or fur, eg a United Nations ruling in 1989 that banned the trade in ivory, although some has since been allowed, if strict rules are observed.
For education and preservation of the environment - many people visit zoos or wildlife parks in order to see and learn about exotic animals from different countries.
Zoos take part in educational activities, teaching children about conservation. They also breed animals that might otherwise become extinct and may pay for research into animal life to help people understand the ecosystem.
However, some people do not think that any animals should be kept in zoos that do not provide their natural environment and that restrict the animals' freedom.
For experiments and scientific developments - animals were used for testing cosmetics but this is now illegal in the UK. Animals are still used to test drugs before they are given to humans, but now other ways of testing have been developed.
Animals have been genetically altered in a laboratory in order to study the effects of genetic diseases and to find out how genes work. There have also been experiments with cloning. Some people worry about the waste of animal embryos in this process.
For entertainment - animals sometimes form part of circus acts. Some people argue that animals enjoy the tasks and are well treated while others believe that no animal should be kept caged and that their right to a natural life is not respected. Similarly, many people believe that keeping monkeys or bears on a chain or using snakes for public entertainment is cruel.