One view accepts that many animals are sentient creatures, and for that reason humans have an obligation to not to avoid gratuitously inflicting pain and suffering on them. However, there is no parallel between Nazi experimentation upon humans for the benefit of other humans and experiments on rats for the benefit of humans. The moral status of humans and animals is very different. That difference does not arise from particular cognitive properties of humans such as self-consciousness, rationality and the ability to communicate. Consequently, only the human species is capable of having and being in a moral community.
Moral community is a necessary condition for having moral rights.
Thus we do not violate the rights of animals when we experiment upon them for the benefit of humans, and it is acceptable to do so. A third view denies that moral standing and moral rights are necessarily tied uniquely to members of the human species as specified in the previous position. 6 Rather, moral standing in creatures is tied to properties of creatures that warrant giving them the protection of morality. If a being has moral standing, it also has moral rights. Certain cognitive properties are frequently invoked as the criteria for assigning moral standing.