The growth process of frogs

Frogs are amphibious animals without tails, with eggs laid in water, fertilized in vitro, hatched into tadpoles, and breathed through gills. After metamorphosis, adults breathe mainly through lungs and skin, but scientists have found that a frog living in the rainforest of Sulawesi Island in Indonesia can give birth to tadpoles. Let's take a look at the growth process of frogs.

Fertilized egg

The breeding time of frogs is about the middle and last ten days of April every year. In the process of reproduction, frogs have a very special phenomenon-hugging each other, male and female holding each other, female ovulation, while male ovulation, sperm and eggs are fertilized in water, which avoids the time lag and greatly improves the fertilization rate.

Tadpole

Tadpoles are an early stage of ontogeny of amphibians. Early tadpoles are round or oval in shape, fish-like and have lateral organs. As there are no pores in the mouth, can not ingest food, after the eyes and nostrils have appeared, there is a sucker under the head, can be used to adsorb on aquatic plants. There are external gills on both sides of the head and have respiratory function. The tail is large and flat, with segmented caudal muscles, and there are membranous upper and lower caudal fins above and below the sarcomere, which can help tadpoles swim in the water.

Young frog

Tadpoles grow limbs after abnormal development, the tail is absorbed, live ashore, due to changes in physiology and environment, vitality is very weak, poor ability to adapt to the environment, such as dry environment, hot sun exposure, heavy rain slapping and so on will make it die.

Adult frog

After a series of growth, the young frogs eventually grow into frogs. Because their skin is bare, they can't effectively prevent the evaporation of water in their bodies, so they can't live without water or humid environment all their lives, and are afraid of drought and cold. So most of them live in tropical and temperate rainy areas, and there are very few species in the cold zone.