What does the animal theory of the ground cow mean?

The first statement refers to an animal, and the second statement refers to a natural phenomenon.

It's sultry in summer, usually in the afternoon, and sometimes I can hear Cleisthenes's roar, which is as deep as an ox, and his voice is deep and powerful, and repeated. People think that this kind of sound is made by an animal called the ground cow, but so far, no one has seen this kind of animal.

Geographically, people who farm fields hear this kind of sound. In order to confirm the existence of this animal, some people look in the direction of the sound, but when people get close, the sound appears in another place, and it always sounds far away.

Others think that this phenomenon is not what animals say, but a natural phenomenon. Interpretation: When the weather is sultry, the moisture in the ground will become gas due to heating, and this sound is made when the airflow gathers and passes through the holes on the surface, so it is called "geogas".

According to the long-term experience of working people, the explanation of this phenomenon generally tends to the latter.