Frogs are often seen in daily life, with a large number and wide distribution in the world. From the category point of view, frogs belong to the amphibian class of Chordata, that is to say, they are amphibians. Frogs, then, must not be mammals, for mammals and amphibians are two very different classes, each of which includes many different animals. Because there is no intersection between them, frogs, as amphibians, cannot belong to mammals at the same time.

Frogs differ in many ways from mammals, in some key features. The first is their breathing mode. Frogs breathe when they are young, and they also breathe with their lungs when they are adults. However, their lung function is not particularly perfect, and they need skin to assist their breathing. A prominent feature of mammals is that their lungs are powerful, and they always breathe with their lungs. In addition, from the perspective of reproduction mode, the reproduction mode of mammals is viviparous, but the mode adopted by frogs is oviparous, which is very different.

As mentioned above, frogs are not mammals, but amphibians. The viviparous reproduction mode is a unique reproduction mode of mammals, and frogs reproduce by viviparous mode instead of oviparous mode. Frogs are dioecious animals, and their reproduction process is carried out in water. Around April every year, it is the peak of frog breeding. Specifically, frogs reproduce by in vitro fertilization, and female frogs lay their eggs in water. After going through the three stages of fertilized eggs, tadpoles and young frogs, frogs will enter the adult stage, which means that they are adults.