Surely there will be some nonhuman animals whose lives, by any standards, are more valuable than the lives of some humans.
Peter SingerWe don't usually think of what we eat as a matter of ethics. Stealing, lying, hurting people - these acts are obviously relevant to our moral character. In ancient Greece and Rome, ethical choices about food were considered at least as significant as ethical choices about sex.
Peter SingerWhatever the reason, for most of the present century, the literature and publicity of the old established [animal welfare] groups made a significant contribution to the prevailing attitude that dogs and cats and wild animals need protection, but other animals do not. Thus people came to think of "animal welfare" as something for kindly ladies who are dotty about cats, and not as a cause founded on basic principles of justice and morality.
Peter SingerTo be a utilitarian means that you judge actions as right or wrong in accordance with whether they have good consequences. So you try to do what will have the best consequences for all of those affected.
Peter Singer