Rats have a survival strategy which is basically to make more offspring in one go than they can handle, so in the wild, many baby rats don't get a chance to live anyway. This makes me feel a bit less bad about animal testing, for you give the rats a bit of time to live in return for an experiment.

Still, they suffer. Sometimes badly and for a longer period of time. But animals don't have the same moral value for us as humans do, so of course we choose them over our own kind when things get deadly or twisted. I'm okay with animal testing because it is convenient for us, humankind, and doesn't cause long-term problems.

So two questions remain as far as I'm concerned: Firstly, what gives us the right to decide about the life of the rats in the first place? And secondly, where lies the border between human and animal morale?

I wouldn't dare say.