[danielam]

I'm not sure where you get the idea that it is clearly established. It most certainly is not. It sounds to me like you are confusing rights with moral obligations in respect to animals. It is a mistake to think that an absence of rights is an absence of moral duties, not to, but in respect to animals.

[KGIII]

Those obligations we have are their rights. Really, go set fire to a horse and see what the courts do to you. The courts punish you because the animal had a right to not suffer and you'd have violated them.

I hunt and fish, so I'm not a granola munching hippy. Yet, animals still have rights. I can hunt and kill a deer. I can't hunt and kill a deer by intentionally causing excessive pain. There are laws against that. Those laws are the animal's rights.

[danielam]

You've confused legal rights with natural rights. Animals don't have natural rights and (generally) don't have legal rights. They're usually legally regarded as property. Anti-cruelty statutes do not presuppose or imply rights. The absence of animal rights does not mean cruelty suddenly ceases to exist.

I didn't say we have obligations (or really duties) _to_ animals but _in respect to_ animals. This is an important distinction.

Animals do not have a right not to suffer, but it is immoral to be cruel toward them. I can, legitimately, cause suffering in an animal if it is an unfortunate effect of, say, acting for an appropriately commensurate human good. I cannot morally do the same to a human being.