A majority of non-human animals are reared for the sole purpose of being slaughtered and consumed by humans. These animals are generally confined in factory farms and face ill treatment because of these space constraints and also as there is a lack of health care facilities for them. Farmers often use chemicals and antibiotics to induce maturity amongst farmed animals which can hence be taken to slaughter houses. They also use these chemicals and antibiotics to produce meatier flesh which is unnatural and causes great discomfort to the animals. The animals are subject to this only because they are not able to defend themselves and they cannot communicate with us. However, this isn’t an excuse that we can use as we still being humans can hear their cries and understand their pain, yet we choose to act indifferently and ignore their pain. Overcrowding of animals under sheds leads to rapid spread of diseases and infections which can affect the farmers and even the meat produced from such animals. So not only are we killing these helpless animals, we are harming ourselves by consuming their meat. Hamburgers, for example, are made from cows that are diseases, disabled and dead. The meat retains the chemicals, hormones and antibiotics that are fed to cattle to accelerate growth and cause weight gain, which is then all consumed by us. Meat also works to raise our cholesterol levels and it is alleged that meat eaters are the prime targets for degenerative diseases such as arthritis and gout. Fish and other seafood is preserved using boric acid, which attacks the liver and the brain. Therefore, we are not only harming animals, but also ourselves.
Then, there are the cases where we use animals to prevent harming ourselves, through animal testing. In animal testing, innumerable animals are experimented on and then disposed of after their use. Others are injured and will still have to live the rest of their lives in captivity. The upsetting thing is that many of these animals received tests for substances that will never see sanctioned for public consumption and use. It is this aspect of animal testing that many view as a major negative against the practice. It gives the impression that the animal died in vain because no direct benefit to humans occurred from the animal testing. There is also the claim that the effect of a drug in an animal’s body is to a certain extent different from the reaction in a human’s. The main criticism is that many believe animal testing is unreliable. Following on that criticism is the argument that because the animals are in an unusual atmosphere, they will be under pressure and possibly suffering from trauma. Therefore, they won't react to the drugs in the same way compared to their potential reaction in a natural environment. This argument further weakens the validity of animal experimentation.
In any case, cruelty to animals, whether it be in the form of hunting, bull fighting or factory farming, is an indication of a society that is uncivilised – it encourages violence and looking down upon other living beings. A society that respects these beings is a more civilised one. Ever since the publication of Charles Darwin’s Origin of Species, we have known that human beings are related by common descent to all other animals, therefore we owe a duty of care to them.
Human beings are infinitely more complex than any other living creatures. Their abilities to think and talk, to form social systems with rights and responsibilities, and to feel emotions are uniquely developed well beyond any other animals. It is reasonable to try to prevent the most obvious cases of gratuitous suffering or torture of animals, but beyond that, non-human animals do not deserve to be given ‘rights’.
Only human beings who are members of society have ‘rights’. Rights are privileges that come with certain social duties and moral responsibilities. Animals are not capable of entering into this sort of ‘social contract’ – they are neither moral nor immoral creatures, they are amoral. They do not respect our ‘rights’, and they are irrational and entirely instinctual. Amoral and irrational creatures have neither rights nor duties – they are more like robots than people. All human beings or potential human beings (e.g. unborn children) can potentially be given rights, but o non-human animals fall into that category.
It is perfectly natural to use animals for our own nutrition and pleasure – in the wild there is much suffering as animals struggle to survive, are hunted by predators, and compete for food and resources. Human beings have been successful in this struggle for existence and do not need to feel ashamed of exploiting their position as a successful species in the evolutionary process.
The fact that we are (incredibly distantly) related to other animals does not mean that it makes sense to talk about them having ‘rights’. This sort of thinking would have absurd consequences: e.g. saying that we should respect the ‘right’ to life of bacteria, or the ‘right’ of the AIDS virus to move freely and without restriction, and to associate freely with other living organisms. We might wish to reduce unnecessary animal suffering, but not because all creatures to which we are distantly related have rights.