Menopause has been observed in several species of nonhuman primates, including rhesus monkeys and chimpanzees. Calorie restriction preserves muscle tissue in nonhuman primates and rodents. The muscles concerned are markedly more innervated in humans than in nonhuman primates. Covance also shares research on animal welfare topics, such as social housing of nonhuman primates. Such infections occur both in humans and nonhuman animals. The hierarchy created among nonhuman animals validates the hierarchies created among humans. Humans are the primary host of the virus, but it also circulates in nonhuman primates. Instances in which nonhuman primates have expressed joy have been reported. Anthropocentrism is the privileging of humans as "subjects" over and against nonhuman beings as "objects". He began his career with nonhuman primate research. Glyphosate can have carcinogenic effects in nonhuman mammals. Itagaki found it more interesting to design nonhuman creatures than human enemies. Charles Darwin helped promote the idea that Africans were no more complex than nonhuman apes. Henry Sidgwick also considers the implications of utilitarianism for nonhuman animals. Animal welfare is the well-being of nonhuman animals.