Taxidermy is the preserving of an animal's body via stuffing or mounting for the purpose of display or study. Animals are often, but not always, portrayed in a lifelike state. The word taxidermy refers to the process of preserving the animal, but the word is also used to describe the end product, which are often called "mounts". The word taxidermy is derived from the Greek words "taxis" and "derma". Taxis means "to move", and "derma" means "skin" (the dermis). The word taxidermy translates to "arrangement of skin". Taxidermy is practiced primarily on vertebrates (mammals, birds, fish, reptiles, and less commonly on amphibians) but can also be done to larger insects and arachnids under some circumstances. Taxidermy takes on a number of forms and purposes, including natural history museum displays, hunting trophies, study skins, and is sometimes used as a means to memorialize pets. A person who practices taxidermy is called a taxidermist. They may practice professionally for museums or as businesses catering to hunters and fishermen, or as amateurs, such as hobbyists, hunters, and fishermen. A taxidermist is aided by familiarity with anatomy, sculpture, painting, and tanning.