Deer is the only deer species in the family Deer and genus Deer. Because its head and face are long and narrow like a horse, its horns are slightly different from other deer, its hooves are wide like cows, and its tail is slender like a donkey, it is also known as the Four Elephant. Its horn shape is unique, opposite to the horns of other deer. The front branch splits into smaller branches, while the back branch hardly splits. The head has a long and narrow snout, the exposed part of the nose is wide, the eyes are small, and the infraorbital glands are very prominent. The limbs are thick and the main hooves are broad and fleshy, with well-developed hanging hooves and a loud knocking sound when walking. Deer prefer swamp and wetland habitats, feeding on green grass and aquatic plants. Good at socializing, good at swimming, and enjoys eating tender grass and aquatic plants.