The perception that animals are smaller versions of humans is one of the main reasons why humans have decided to experiment on animals; however, simply put, this claim is incorrect. Although humans and animals (mammals) do in fact share many genes, the way in which these genes are expressed differs immensely. To deal with this problem, scientists try to genetically alter animals to represent humans more accurately. Yet, this method does not produce accurate results. For example, in an experiment conducted, genes in six mice were altered to look like human genes. These mice all shared the genetic mutation for Fragile X syndrome; however only in some of the mice did this mutation prove to be lethal (Akhtar 1). This depicts how inaccurate the results can be when dealing with genetically modified animals. In addition to the gene expression being different, humans have lengthier life expectancies than many animal test subjects, as they have different metabolic processes and are “exposed to a multitude of different environmental factors over [their] lifetimes” (“5 Reasons Testing on Animals Makes No Sense”). Therefore, certain chemicals do not react the same way in animals as they do in humans.  For example, HIV does not progress the same way in a chimps’ body as it does in a human’s and certain pesticides do not harm monkeys, but can kill humans. According to dosomething.org, “92% of experimental drugs that are safe and effective in animals fail in human clinical trials because they are too dangerous or do not work,” proving that animals are not the best test subjects (“11 Facts About Animal Testing”). Additionally, of the 8% of the drugs that get approved, approximately half of these products get relabeled, as unexpected side effects appear that were not found when tested in animals.  As one can see, it is evident that the results achieved after research done on animals would not be as the same results achieved in humans, rendering animal test subjects useless.