The terms epic tale and myths are certainly sometimes confused because they share similarities. However, each have distinctive characteristics that can help you to identify them.
Myths and epic tales, for example, both have larger than life characters. Additionally, they both tell a story rather than simply explaining a cultural trait, like religion, for example. Myths and epic tales also tend to have been passed down for many years, developing through the oral tradition.
However, they each have certain defining characteristics that allow one to identify them as either a myth or an epic tale. Though myths have a larger than life character, they do more than tell a story about him. A myth will explain a natural event, religious practice or cultural element. The epic tale revolves around the single, heroic character and tells the story of his adventures or life through several episodes or story parts. If it tells the story of an entire culture, it does so through the eyes and actions of the heroic character over the course of many years of his life.
It can be difficult to discern the difference between these two genre and you may sometimes find that you disagree with how a publisher has labeled a particular text due to the characteristics these two genre share.
Epic tales and myths were common features of society in the ancient world and persist in some form or other even today. Both generally deal with larger-than-life characters: kings, queens, heroes and warriors, major events such as wars and disasters, supernatural events, and great stories of love, passion and revenge and so on. Myths however concentrate more on gods and goddesses and other figures generally removed from the earthly realm whereas epic tales also include figures that are at least partly grounded in historical reality. Epic tales are long narratives whereas some mythic tales might be quite short.
In the ancient world, epic tales such as the Iliad in Greece and The Epic of Gilgamesh in Mesopatamia are equally about legendary leaders and warriors as well as about gods and goddesses; the interaction betwen human and divine figures is all-important.