There is, in fact, rough justice in the common quip that "we will recognize the rights of animals whenever they petition for them." The fact that animals can obviously not petition for their "rights" is part of their nature, and part of the reason why they are clearly not equivalent to, and do not possess the rights of, human beings. And if it be protested that babies can't petition either, the reply of course is that babies are future human adults, whereas animals obviously are not.
(Murray Rothbard, Rights of Animals)
