Question 12: Are animals too different from people for animal testing to be valid?

Obviously there are differences between animals and people. But under the skin, the biology of humans and other animals is similar. We have the same organs, controlled by the same nerves and hormones, as many other species. Where there are differences, researchers know about them, and such differences can actually help scientific understanding of a particular problem. Many animals suffer quite naturally from the same diseases as humans, and can be used to study those diseases.

Citation PETA

http://www.peta.org/issues/animals-used-for-experimentation/animal-testing-bad-science/

animal experimentation

http://www.buowl.boun.edu.tr/teachers/sample%20student%20essays/animal%20experimentation%20ayse%20ipek.htm