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Why does a tadpole’s tail shrink during metamorphosis?
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amphibian
Banded fire salamander (Salamandra terrestris).
During the metamorphosis of a tadpole into an adult frog, the tail shrinks because it is resorbed by the body. This process is triggered by hormones, specifically thyroxine, which circulates in the blood and signals the tail tissues to degenerate.123
As the tail muscles break down, the cells are destroyed and devoured by phagocytic cells. This resorption is a key part of the transition from an aquatic larval stage to a terrestrial adult form, allowing the animal to repurpose the biological material as it develops limbs and other adult structures.312