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
Deception in animals in a way that other animals misinterpret what is happening to the advantage of the agent. Some of the evidence for this is anecdotal, but in the great apes in particular, experimental studies in ethology suggest that deception is actively practised by some animals. Some types of deception in animals are completely involuntary (e.g. disruptive coloration), but others are under voluntary control and may involve an element of learning. Most instances of voluntary deception in animals involve a simple behaviour, such as a cat arching its back and raising its hackles, to make itself appear larger than normal when attacked.