The question is whether or not animals have rights — and, it’s a good question.
Those on the “yes” side say that they have rights because they can feel pain. This means that they share a significant characteristic with human beings and we wouldn’t want to say that some human beings don’t have rights, so animals must have rights as well.
Those that argue for animal rights don’t go so far as to say they have the right to vote etc.. but rather, they have the right not to be killed. In effect, they say they have negative rights — the right to be left alone. In particular, they object to animals being used as food and, in some cases, used in agriculture.
I’m not sure that animals have rights — but that’s because I think rights ought to be conceived of in terms of the median abilities of a similar group of individuals. So, while some animals are extraordinary in terms of their intelligence and “reasoning” abilities, as a group they don’t have the same abilities as an average group of humans. That’s the difference.
Human beings can articulate commitments to one another. They can reason abstractly about their long-term wants, wishes, needs, and desires. They are able to plan, educate themselves, and change a life that isn’t working out as they’d like. All of these activities are evidence of autonomy, which Kant connects to inherent worth.
It simply isn’t the case that my cat, amazing as she is (I have to write that, just in case I’m wrong and she CAN read), doesn’t show evidence of autonomy in the same way as her humans. She works mostly on instinct and stimulus-response. She sleeps in the sun when it’s sunny and under the covers when it’s cold etc.
It’s possible that when she’s living with other cats — my ex. has “Spock”, a black cat whom Tera (my cat) lived with for several years — she makes agreements with him, enforces infractions of those rules etc. From our human point of view, cats in a community do seem to have their own rules, punishments, and rewards — and those rules are inconceivable to their humans.
I will say that when I adopted Tera I made a commitment to see to her care. I’m not sure whether that obligation is to the cat herself or to the rest of society. If I abandoned her and society had to take care of her, either in a shelter or some other way, I’d have wronged society in a small way — but, perhaps I’d harm Tera in a bigger way? If I can no longer give her a good home and care for her, I have an obligation to her to find her a suitable new home — whether it’s with my ex. or with someone else.