The Minbari are a humanoid, mammalian race. One visible difference between human and Minbari physiology is their headbone. This "antler-like" structure creates a protective sheath around the back of the head to provide extra protection where the internal skull can be fragile. The head bone is not present at birth, but gradually grows out. They differ in size, configuration, and texture. The Minbari have elaborate rituals for the shaping, honing, and cutting of one's crest. The female headbone generally has a smooth curve on both sides ending in a singular point at the back. Male Minbari headbones tend to rise at several peaks on both sides, ending at a point in the back. Additionally, the crest is sometimes shaped in tune with one's caste. Thus a female Shi Alyt might wish to sculpt her headbone into a vicious spiky crown as warrior caste males do. Worker Minbari do not have much of a stylized manner of bone-carving as the other castes. The older a Minbari gets, the more the headbone creeps forward across the top of the head. Other differences with human physiology include a slightly more raised and obvious spinal structure and a different blood type. Minbari have remarkable constitution and strength, however, consumption of alcohol will make a Minbari paranoid and psychotically violent. Small differences aside, the Minbari are probably the most biologically similar to humans than any other galactic race.