Hatching is the process by which an embryo develops inside an egg and eventually breaks free from its shell. This process is most commonly associated with birds, reptiles, and some fish. During hatching, the embryo absorbs nutrients from the egg yolk and grows until it is ready to emerge. The timing of hatching can vary depending on the species and environmental conditions. In birds, hatching typically occurs after a specific incubation period, where the parent birds keep the eggs warm. Once the embryo is fully developed, it uses a specialized structure called an egg tooth to crack the shell. After hatching, the young animal, often called a hatchling, is usually dependent on its parents for food and protection.