How can you determine an animal's will? Or whether it consents or does not? Are animals even capable of volition? Common sense tells us you can not, and that animals probably do not possess the mental faculties to understand their situation and to give or decline consent to something a human does to it. Animals, after all, are not humans; and while it can be argued that humans are merely animals, too, we are the only sentient animals that we are aware of.

Whether you choose to acknowledge it or not, this fact gives us a special rank in the food chain and I daresay affords us dominance over this planet and any other we may inhabit (unless, of course, another sentient species had happened to populate it first).

Just why should animals be granted the same rights that are reserved for man? They can not petition for rights, they do not voluntarily contribute to our society and our continued survival as a species, nor do they make any attempt to integrate with our culture. Animal rights, therefore, are a preposterous notion worthy of nothing but its immediate dismissal as an attempted mockery of mankind.

If you're still not convinced, then follow me to the logical conclusion of the line of thought that leads one to believe in such a silly thing as "animal rights."

Why is it that proponents of animal rights never stop to consider the rights of bugs, insects, plants, bacteria, viruses, and parasites alongside those of animals? Plants, insects, bacteria, viruses, and parasites, after all, are living things, too. Obviously they must possess some kind of inherent will to live, just as they purport animals to have. Why should we not respect their rights as well?

What, pray tell, differentiates the grain farmer from the pig farmer? Does the grain farmer not senselessly slaughter millions of crops every harvest for the manufacture into foodstuffs to feed the greedy, starving human masses? Or how about the microbiologist? Does he not conduct his horrid experiments on viral strains to find new and better ways of murdering them before they can infect another human soul? The virus is only exercising its right to live, even if its mode of living is at the expense of another living organism.

Think of it this way: if animals are allowed to become the property of humans, they may never become extinct. Why, you ask? Because so long as there is a demand for animals, people will do their best to ensure those particular animal populations never become extinct. Cows are in no danger of extinction, because we breed them specifically for industrial purposes: their milk for dairy products, their meat for food and sustenance, their hides for fashioning into coats and other miscellaneous uses. We will probably never see the extinction of deer, because so many people enjoy consuming venison and hunters love to hang them from their mantles. The same applies to fishermen, zoos, wildlife preserves, and so fourth.

Conservation, therefore, is a direct offset from peoples' desires to consume animals! Even if that consumption is restricted to merely owning an animal as a pet.
I originally posted this earlier today on another forum. It's actually part of a post I made in response to the topic of beastiality. The only ommission was the final paragraph, however the rant about animal rights was provoked by the OP's insinuation that animals, somehow, possess rights, or at least ought to. I thought this would make an excellent discussion, as I believe there are a few PETA types lurking around here.

Further reading on animal rights and why they are ridiculous is available here.