Craniate with well-defined heads, thus excluding members of the chordate subphyla Tunicata (tunicates) and Cephalochordata (lancelets), but including Myxini, which have cartilaginous skulls and tooth-like structures composed of keratin. Craniata also includes all lampreys and armoured jawless fishes, armoured fish, sharks, skates, and rays, and teleostomians: spiny sharks, bony fish, lissamphibians, temnospondyls and protoreptiles, sauropsids and mammals. The craniate head consists of a brain, sense organs, including eyes, and a skull. In addition to distinct crania (sing. "cranium"), craniates possess many derived characteristics, which have allowed for more complexity to follow. Molecular-genetic analysis of craniates reveals that, compared to less complex
Cruelty to animals costs and benefits and vary in their conclusions as to the allowable treatment of animals. Some utilitarians argue for a weaker approach which is closer to the animal welfare position, whereas others argue for a position that is similar to animal rights. Animal rights theorists criticize these positions, arguing that the words "unnecessary" and "humane" are subject to widely differing interpretations, and that animals have basic rights. They say that the only way to ensure protection for animals is to end their status as property and to ensure that they are never used as commodities. Throughout history individuals have condemned