We are merely personifying animals, giving them qualities that they do not have. He also fails to realize that there is more than one kind of suffering. Even if his equality community based on suffering is tenable, we would still have reason to treat animals differently from human beings because we can suffer and derive joy under much more circumstances and to greater degrees than they can. I would claim that Singer himself is a speciest because he is allowing the lesser interests of other species to override the greater interests of man. After our discussion of the different kinds of suffering and happiness that humans and animals experience, I feel that a venture into whether animals have rights is not misguided but necessary.
Rights are the artificial constructs defining how different parties agree to treat each other.
Beings that have not developed enough to fully understand rights do not have access to their full set of rights. This is why parents have jurisdiction over their children until they become independent. Organisms that do not have the lifetime potential to understand rights, however, do not deserve to be given rights, because to do so would jeopardize ours. You cannot reason with a leopard to not attack you if it's hungry. To give the leopard rights would be absurd because it will not respect yours.