The hoof is actually a horse's toenail.

Through fossil research has confirmed that the ancestor of the horse genus of animals - Eocene horse appeared in North America 55 million years ago, its body is like a fox-like size, to the succulent young leaves for food, the forefoot has four fingers, the hind foot has three toes.

Subsequently, topographic, climatic, and ecological changes occurred in the natural world, resulting in the emergence of open inland plains, and the evolution of the horse gradually adapted to these changes. The evolution of the horse has gone through major stages of development such as the Beginning Horse, the Middle Horse, the Original Horse, the Upper New Horse and the True Horse.

The main evolutionary features are: the body increased; body height increased, body height from the original 40cm to more than 120cm; toe from the three or four toes evolved into a single toe (single hoof), in order to facilitate running; teeth from the low crown of the caruncle structure to the high crown, hard teeth, teeth, wide and wrinkled structure, in order to facilitate hay harvesting; brain capacity increased.

Composition of the hoof

1, hoof margin: hoof margin is the hoof and the skin connected to the glabrous part of the hoof, width of about 0.5 centimeters, semi-annular. The dermis of the hoof margin forms very sparse fine papillae, and the tips of the papillae are pendulous. The keratin produced by the epidermal germ layer of the hoof margin covers the hoof wall downward, forming the outermost layer of the hoof wall, called the glaze or hoof paint.

2, hoof crown: the hoof crown is located below the hoof margin, above the hoof wall. In the hoof crown keratin has a width of about 1.5 centimeters of the hoof crown groove to accommodate the hoof crown dermis. There are many papillae on the surface of the dermis of the hoof crown, the papillae are cone-shaped, the tip is downward, and the surface of the papillae is covered with the epidermal hair layer. The cuticle produced by the hair layer forms the protective layer of the hoof wall.

3, hoof wall: hoof wall epidermis is the thickest, can be distinguished into three layers: glaze layer, protective layer (coronal layer) and cuticle layer. Cuticle leaflets embedded in the dermis between the leaflets, so that the hoof wall cuticle and hoof wall dermis firmly combined. The cuticle lobules produce yellowish keratin, thus forming a yellowish white line on the negative edge of the hoof wall, also known as the yellowish line.

The bottom edge of the hoof is made up of the outer edge of the hoof sole, the white line and the lower edge of the coronary layer of the hoof wall*** with the same composition, is the part of the horse body weight. Hoof wall corium is usually divided into hoof tip wall, hoof side wall and heel wall. The heel wall to the hoof bottom folding part of the hoof is called the hoof branch, the folding angle is called the hoof branch angle.

4, the bottom of the hoof: the bottom of the hoof is located in the white line, in front of the hoof fork and lateral. The anterior part of the horn of the sole surface is the sole body, and the posterior part forms two sole branches and is connected to the hoof fork and hoof branch.