Animals aren't just toys we were given to research diseases as Con said. He/she just gave one example and did it very generally. Animals should be used for experiments but there should always be limits. Animals should not be experimented on if the experiment can cause any type of mental, psychological, or physical harm.
"The question should not be whether they can talk, but rather, can they suffer?" my favorite quote describing how animals deserve rights.
They can feel pain just as we can, yet most of them tend to be smaller and less capable of defending themselves, which is where we come in, we need to give them rights to protect them from corrupt humans.
A contemporary philosopher and animal rights activist named Tom Regan offers very compelling arguments in support of animal rights; it is ethical and just to concede rights to animals because to treat them with less respect would be prejudicial. If humans want to live up to to their ethical expectations, then we must act compassionately and not treat animals as commodities to be used. Abusing animals is uncivilized.
Race could benefit to much from experiments done on animals that have similar immune systems. So what, a dog dies because we just found a way to keep radiation away from the human body temporarily or some breakthrough like this. Rats, whales, whatever as long as they don't drive them to extinction.