How do tadpoles breathe?

External gills.

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.

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. Extended information

After two months of development, the tadpole metamorphoses into a young frog

Frogs often live in rivers, ponds, rice fields, etc., mainly in the grass near the water, and sometimes It can also lurk in water. Most of them are active at night and feed on insects as their main food. They also eat some snails, snails, shrimps, small fish, etc. Most of the insects they eat are agricultural pests. Some people estimate that a frog can eat 70 bugs a day and eliminate 15,000 pests a year.

Therefore, frogs are animals that are beneficial to agriculture and should be protected. When the weather gets cold in late autumn, frogs hibernate at the bottom of the water or in caves, and return to the water to breed when the weather warms up the following spring. During the breeding period, many male frogs often gather in the same area and chirp loudly and continuously. This is the so-called "frog pit."

In fact, this is a courtship behavior of male frogs. They sing to attract the opposite sex and form a mate. After pairing, the female frog begins to ovulate into the water, about 3,000-6,000 eggs each time; at the same time, the male frog discharges sperm into the water. Sperm and egg cells combine in water to form fertilized eggs, which develop into tadpoles after 4-5 days of incubation.

Tadpoles must live in water, swim with their tails, breathe with their gills, and eat plant foods such as diatoms and green algae. After two months of development, the tadpole metamorphoses into a young frog. Its tail gradually disappears, its body length shortens, and it begins to live on land. Its food habits also begin to change to mainly animal food. It takes about three years from juvenile frog to sexual maturity.

Baidu Encyclopedia-Tadpole