to wear more evenly. Because many modern horses often graze on lusher, softer forage than their ancestors, and are also frequently fed grain or other concentrated feed, it is possible some natural wear may be reduced in the domestic horse. On the other hand, this same uneven wear in the wild may have at times contributed to a shorter lifespan. Modern wild horses live an estimated 20 years at most, while a domesticated horse, depending on breed and management, quite often lives 25 to 30 years. Thus, because domesticated animals also live longer, they may simply have more time to develop dental issues that their wild forebears never faced. Typical wear patterns Typical wear patterns in horses include: Cups: are hollow and rectangular or oval in shape, appearing on the tables of the permanent incisors, that wear away over time. In general, cups are worn away on the lower central incisors by age 6, the lower intermediates by age 7, and corners at age 8. The cups of the upper central incisors are worn away by 9 years of age, the upper intermediate incisors by 10, and the corners by 11. When all the cups are gone, the horse is referred to as smooth mouthed. In the past, dishonest dealers would "bishop" the teeth of old horses, usually by burning an indentation into the teeth, to imitate cups: but this practice was detectable by the absence of the white edge of enamel that always surrounds the real cup, by the shape of the teeth, and other marks of age about the animal. Pulp mark/Dental star: After some wear has occurred on the teeth, the central pulp cavity is exposed, and the tooth is marked by a "dental star" or "pulp mark" that is smaller than the incisor cups. These begin as a dark line in front of the dental cup, which grows in size and becomes more oval in shape as the cups are worn away. Dental stars are usually first visible at age 6, on the animal's lower central incisors, and very visible by age 8. They appear on the lower intermediates by age 9, and on the other incisors between the ages of 10–12 years. Hook/Notch: A hook appears on the upper corner incisor around age 7, and disappears by age 8. It reappears around age 13, again disappearing about 1 year later. Galvayne's Groove: The Galvayne's groove