Tadpole

Ten-day-old tadpoles

A tadpole (also known as a pollywog) is a larval frog, toad, salamander, or newt. In this stage it breathes by means of external or internal gills, is at first lacking legs, and has a finlike tail. As a tadpole matures, it metamorphoses by gradually growing limbs and then (in the case of frogs and toads) absorbing its tail.

Most tadpoles are herbivorous, subsisting on algae. In a few species, some tadpoles turn cannibalistic under harsh conditions and feed on other tadpoles living in the pond.

Embryos (and one tadpole) of
the wrinkled frog (Rana rugosa).

Tadpole is a 2002 film directed by Gary Winick about a boy who falls in love with an older woman. See: Tadpole (movie).

In physics, a tadpole is a Feynman diagram with one external leg (the name is due to Sidney Coleman) and it encodes a one-point function (correlation function of one field). See tadpole (physics). In the US Navy, a pollywog is a sailor who has not yet crossed the equator while on a ship.