Crake is a small to medium-sized bird that lives on land, swamps and water. It has short, wide and round wings and often can't fly. In danger, it would rather run away from the enemy. But some species migrate. Their bodies are short and flat, so that they can pass through dense plants. Small head, short or medium neck, cervical vertebra 14- 15. The mouth is usually slender, slightly longer than the length of the head, and sometimes slightly bent downward. Some kinds of mouths are short and flat, or thick and conical. Gallicrex, Gallinula and Fulia also have horny frontal plates (forehead and nails) connected to their beaks. The wings are short, wide and round, the primary flight feathers are 10, and some species are short11; The second flight feather 10-20, the fifth one is missing. The tail is short with 6- 16 tail feathers, usually 12. The tail is square or round, and the tail feathers often shake or tilt to show the signal color of the feathers under the tail. Legs are long to short, usually legs and toes are slender and have hind toes. The toes of patients with Porphyra and porphyria stick out to walk on floating plants, and the toes of cephalopods stick out to form flippers for swimming.
The body color is mostly brown, chestnut, black, blue-gray, gray, and the feathers of the genus Purple Water Chicken are flashing purple, blue or green. The upper body often has stripes and spots, but some kinds of feathers are single in color; There are often stripes on both sides, and the perianal and tail feathers are brightly colored. Male and female feathers are usually similar, and a few species of feathers are hermaphroditic, such as Dong chicken. The feather color of adult birds is similar in non-breeding period and breeding period. The feather of a chicken is black or dark brown. The feathers of young birds are similar to those of adults, but the stripes are not as obvious as those of adults. Some kinds of young birds have bright colors on their heads, throats or necks, which are considered as feeding signals.