Why does a tadpole’s tail disappear during metamorphosis?

During the metamorphosis of a tadpole into an adult frog or toad, the tail disappears because its tissues degenerate and are consumed by phagocytic cells.1

This process is regulated by hormones, specifically thyroxine, which circulates in the blood and triggers different responses in various tissues. While thyroxine stimulates the growth of limbs, it simultaneously causes the muscles of the tadpole’s tail to break down. This resorption allows the body to transition from its aquatic larval form to its terrestrial adult form.123