Tadpoles

Tadpoles are the aquatic larval stage of frogs and toads, amphibians that begin life in water. They hatch from eggs laid in freshwater by the adult, often in gelatinous clusters or strands attached to vegetation. Tadpoles are typically limbless, have gills, a tail, and a relatively simple digestive system. They breathe mainly through gills and the skin, and some species have external gills during early development.

Development: After hatching, tadpoles grow and feed on algae, plant material, and detritus. Their bodies change during metamorphosis when a hormone-driven process leads to the growth of hind legs, then forelegs, the reabsorption of the tail, and changes to the mouthparts and digestive tract. Lungs form and replace gill respiration, enabling the juvenile to become air-breathing. The metamorphosis period generally lasts weeks to months and is influenced by temperature, food availability, and season.

Ecology and habitat: Tadpoles inhabit freshwater environments such as ponds and slow streams. Light availability, water chemistry, and presence of predators shape their development and survival. Some species are herbivorous as tadpoles, feeding on algae and detritus; others are omnivorous or carnivorous as older juveniles. Predators include fish, birds, and larger amphibians; cannibalism has been reported in some species.

Significance and conservation: Tadpoles play a role in aquatic ecosystems by controlling algal growth and serving as prey. Amphibian populations worldwide face threats from habitat loss, pollution, climate change, and disease such as chytridiomycosis, which can disrupt metamorphosis and survival.