When do tadpoles appear?

Available from April to May.

Tadpoles, written as "Ke Dou" in ancient times, are the larvae of frogs and toads, also known as toad eggs. Newly hatched tadpoles have a spindle-shaped body with no limbs, mouth and internal gills. They have a long tail with flat sides and branched external gills on both sides of the head. They are adsorbed on aquatic plants and rely on the remaining yolk in the body to provide nutrients. . Mainly live in groups.

As tadpoles mature, they begin to metamorphose, gradually growing limbs and then (in frogs and toads) gradually losing their tails through apoptosis (controlled cell death).

Extended information

Tadpoles are a primary stage of amphibian ontogeny. Early tadpoles have a round or oval body, a fish-like appearance, and lateral line organs. Since there are no holes in the mouth, food cannot be taken in; eyes and nostrils will appear one after another; there are suckers under the head, which can be used to absorb water plants. There are external gills on both sides of the head, which have respiratory function.

The tail is large and flat, with segmented tail muscles inside. There are membrane-like upper and lower tail fins above and below the myotomes, which can help tadpoles swim in the water.

After the mouth appears, it scrapes algae with the horny teeth on its lips and begins to live independently in the water. When the sucker disappears, the external gills also shrink; as the pharyngeal skin folds and the body wall heal, a gill cover is formed, and a water outlet hole is retained on the left side of the body surface, or in the middle or rear of the ventral surface. The inner gills are used for breathing, and with the development of lungs, they can also breathe free oxygen on the surface of the water.

At a certain stage of development, some grow back limbs first, then differentiate into 5 toes at the end, and then grow forelimbs from the gill cover, such as frogs.