The use of experimentation on animals has been around for centuries. Animal testing is used mainly for developing new drugs and vaccines for human beings. However, many drugs used for animals in veterinary medicine have also been developed by testing on animals. Animal testing has brought forth many drugs that have saved human and animal lives, but these lab animals eventually end up dying and are subjected to cruel procedures. The lab animals also live in stressful living conditions and sometimes they aren't accurate in determining how a drug will affect a human being. There are many faults to animal testing which is why we should be opposed to it.
Billions of lab animals die each year in the United States alone due to animal testing. Lab animals aren't just rats. Cats, dogs, monkeys, rabbits, and guinea pigs are all used for animal testing. Most of the tests these animals are subjected to are very painful and can cause a lot of stress on the animals. Sometimes the experiments that testers do have nothing to do with what they are researching or trying to develop.
Another downside is that the animals live in poor conditions. They are put into tiny cages and have to sleep and eat among their own feces. They get no exercise and are kept away from the other lab animals. Many times they are kept in the dark and get no sunlight. This is unhealthy and very stressful on the animals.
Lab animals are also not always a reliable source of what medicines and vaccines will do to human beings. Human body systems and animal body systems are different, so drugs will react different with each. If you have heard of a drug recall, this is because a lab animal had no ill side effects to a drug that many humans did. Also, the conditions in which the animals live in contribute to how they react to a drug. They live in unhealthy environments, so this can affect the way their bodies react to a drug.
There are thousands of reasons why animal testing is wrong. Animals cannot give their consent to be tested on, and therefore people believe it is okay to do so. Billions of animals die and results aren't always accurate. Animals testing should be done away with and new alternatives made. Hopefully with technological advances, animal testing will become a thing of the past.