In the third year of Belshazzar, Daniel had another vision. (Chapter 7 took place in the first year.) The mention of the years of Belshazzar at the beginning of each chapter suggests a co-relationship between the diverse animals. In Chapter 8 the symbolism starts with the second universal empire, Media-Persia, because the events of this chapter occurred at the end of the Babylonian Empire.
Next Daniel saw the ram “pushing westward,” which was when Xerxes, the fourth king, tried to invade Greece, going down to Athens. Even though his army was defeated and he retreated back to his own capital, he was still the mighty power of that time. What caused his defeat? Nature—a storm destroyed his bridge of boats. After Xerxes’ reign, the Persian Empire expanded northward. (There were approximately nine kings before Alexander the Great of Greece.) Regarding the southward push, the Persian power went south to Egypt under Cambyses, for example.
Notice that the Media-Persia Empire is described as both a ram “pushing” and a bear, which is large and ponderous. A bear’s motion is very slow, but because of its size and loping gait, it actually moves faster than appears. The fact that a bear hugs its prey to death pictures the siege tactic of Media-Persia. With huge armies and a great amount of supplies, the Persian armies could take their time in subduing other peoples. They won by sheer numbers.