"Animals are not as intelligent or advanced as humans."

If possessing superior intelligence does not entitle one human to abuse another human for his or her purposes, why should it entitle humans to abuse nonhumans?

There are animals who are unquestionably more intelligent, creative, aware, communicative, and able to use language than some humans, as in the case of a chimpanzee compared to a human infant or a person with a severe developmental disability. Should the more intelligent animals have rights and the less intelligent humans be denied rights?

It is not intelligence, but the ability to suffer that matters. As philosopher Jeremy Bentham wrote, "[A] full-grown horse or dog is beyond comparison a more rational, as well as a more conversable animal, than an infant of a day, or a week or even a month old. But suppose the case were otherwise, what would it avail? The question is not, can they reason? Nor, can they talk? But can they suffer?"