Hatchlings

A hatchling is a young animal that has recently emerged from an egg. The term is used across many animal groups, including birds, reptiles, fish, amphibians, and invertebrates. Hatchlings typically have developmental traits that distinguish them from eggs and adults, and their survival often depends on species-specific life history, parental care, and environmental conditions.

In birds, hatchlings are classified as altricial or precocial. Altricial hatchlings hatch blind, featherless, and dependent on parental feeding and brooding. Precocial hatchlings are relatively mobile and covered with down or feathers soon after hatching, and they may follow parents or forage with limited assistance.

In reptiles, hatchlings often resemble miniature adults and can fend for themselves shortly after birth, though parental care and nest guarding occur in some species. Some reptiles exhibit temperature-dependent sex determination, where the incubation temperature influences the sex of hatchlings. Nesting sites and emergence timing vary by species.

For fish, eggs hatch into free-swimming larvae or fry that often look very different from adults and may require specific foods to survive. Amphibian eggs hatch into aquatic larval forms such as tadpoles that undergo metamorphosis into adults. Insects and other invertebrates may produce hatchlings that are nymphs or larvae, depending on the life cycle; metamorphosis may be complete or incomplete.

Hatchling survival is influenced by predation, food availability, and habitat quality. Some species provide parental care or nest guarding, while others rely on rapid development and early independence. The term hatchling emphasizes the period immediately after emergence, with other developmental stages described as fry, nymph, larva, or juvenile.