Rajidae is a family of cartilaginous fish commonly known as skates. They are closely related to rays and are characterized by their flattened bodies, large pectoral fins, and long tails. Skates are typically found in temperate and polar waters, often resting on the ocean floor. These fish are known for their unique reproductive method, laying eggs in protective cases called "mermaid's purses." Skates primarily feed on small fish, crustaceans, and mollusks, using their flattened bodies to blend into the seabed and ambush prey.