What role did tortoise shells play in ancient times?

In ancient China, when tortoise shells were roasted with fire, there was a "click" sound, which was often understood as a message from God. Another important basis for burning Oracle Bone Inscriptions's content is the tortoise shell crack that appears at the same time as the tortoise shell sound, which is full of infinite mystery in the eyes of fortune tellers. In addition, Oracle Bone Inscriptions is the abbreviation of tortoise shell animal bone script, also called tortoise shell script.