Tadpole Lifecycle Introduction
The tadpole, or polliwog, is an amphibian's larval stage. After hatching, it undergoes remarkable transformations before becoming a frog. This journey is a fascinating example of metamorphosis in the animal kingdom.
Eggs to Hatching
Tadpoles hatch from jelly-like eggs laid in water. Depending on the species and temperature, hatching can take 3-25 days. Initially, they feed on the remaining yolk, which is actually inside their guts.
Early Tadpole Stage
Newly hatched tadpoles possess gills for underwater breathing. They adhere to vegetation using mucous glands, and their diet consists of algae and plant tissue. This herbivorous stage is critical for initial growth.
Developing Hind Legs
After about a few weeks, hind legs sprout. Surprisingly, the immune system recognizes the developing legs as foreign, and a specialized protein, Thrombospondin-1, prevents an immune attack on the new limbs.
Forelimbs and Lungs
Forelimbs emerge, and lungs begin to develop, preparing the tadpole for terrestrial life. During this time, their diet shifts towards a carnivorous one. They start coming to the surface for air.
Tail Resorption
Tadpoles reabsorb their tails using enzymes and apoptosis (programmed cell death), redirecting energy and materials to the growing body. The tail's cells are not wasted; they fuel the final transformation.
Froglet to Adult Frog
The metamorphosis culminates in a froglet—a juvenile frog with a tiny tail stub. It takes some species up to three years to fully mature. Adult frogs may return to water to breed, starting the cycle anew.Surprising Tadpole Diet
Some tadpoles turn cannibalistic when food is scarce, eating smaller tadpoles to survive. This extreme behavior helps balance population and resources in their environment.
What is a tadpole's initial diet?
Algae and plant tissue
Remaining yolk inside guts
Small insects and larvae
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