Every Culture on Earth Has a Flood Myth and the Similarities Are Specific Enough That Historians Are Not Sure What to Do With That
I want to start with the specifics because the specifics are what make this interesting. This is not just “lots of cultures have flood stories.” Lots of cultures have creation stories and trickster figures and underworld myths too, and some of that overlap is explained by shared human psychology and universal narrative structures.
The flood myths are different. They share details that narrative structure alone does not explain. A man receives divine warning that a catastrophic flood is coming. He builds a vessel. He brings animals onto the vessel. The flood destroys everyone else. He survives. The waters recede. He sends out a bird to test whether land has returned. He makes land somewhere elevated and offers sacrifice. Finally, he is blessed or rewarded by the divine force that saved him.
That sequence appears in the Mesopotamian Epic of Gilgamesh. It appears in Genesis. It appears in Hindu scripture. And it also appears in the Aztec flood tradition, in Greek mythology with Deucalion, in Norse mythology, in Chinese tradition, in Aboriginal Australian oral histories, in the flood myths of the Ojibwe and dozens of other Indigenous North American nations. The bird detail is in multiple independent traditions. The elevated refuge is in multiple independent traditions. The divine warning to a specific righteous individual is in multiple independent traditions. Historians are aware of this. They are not entirely sure what to make of it.
The Near East Connection
The clearest case of direct transmission involves the Mesopotamian and Biblical versions. The Epic of Gilgamesh predates the Biblical flood narrative. The flood hero in the Gilgamesh epic, Utnapishtim, receives warning from a god, builds a large vessel, brings animals and his family aboard, survives the flood on a mountain, and sends out three birds in sequence to determine when the waters recede. He then makes an offering on a mountaintop.
Noah receives warning from God, builds a large vessel, brings animals and his family aboard, survives on a mountain, sends out birds in sequence to determine when the waters recede, and makes an offering on a mountaintop.
Scholars generally accept that the Hebrew flood narrative was influenced by Mesopotamian tradition. The Judean exile to Babylon in 586 BCE brought Hebrew scribes into direct contact with Mesopotamian literature. The Epic of Gilgamesh was widely known. The word Noah uses in Hebrew to describe the pitch he seals his ark with appears only once in the entire Hebrew Bible and almost certainly derives from the same Akkadian word used in Gilgamesh and the earlier Atrahasis Epic.
This particular overlap has an explanation. Cultural contact, literary borrowing, scribal transmission. The Near Eastern flood myths are probably variations of the same original tradition.
The Part That Does Not Have a Clean Explanation
The Australian Aboriginal flood traditions are the problem. Australia has been separated from the rest of the world for somewhere between 50,000 and 65,000 years. There was no contact between Aboriginal Australian cultures and Mesopotamian or Biblical traditions. And yet the flood motifs appear: catastrophic water, survival of a selected group, a world remade after the deluge.
The same applies to flood traditions in the Americas, where civilizations had no contact with the Old World before European arrival. The Aztec tradition includes a man and woman warned by a god to survive in a log while the world floods. The Ojibwe tradition involves a hero who builds a raft and collects animals. These parallel the Near Eastern versions in structure without any plausible route for transmission. Three explanations circulate among researchers. None of them is fully satisfying.

The Three Explanations
The first is universal human experience. Floods happen everywhere. Floods are among the most devastating natural disasters humans encounter. Cultures everywhere have experienced floods, and floods that wipe out communities could plausibly generate local stories about world-destroying deluges. The survivors of any sufficiently catastrophic local flood might describe it as the end of everything.
The problem with this explanation is that it accounts for flood stories without accounting for the specific recurring elements. You can explain why people would tell stories about floods. You have a harder time explaining why the bird-sending sequence appears in Mesopotamia, in Genesis, and in independent traditions elsewhere.
The second explanation is a real event. Some geologists and archaeologists have proposed that there was a catastrophic flood in the Black Sea region approximately 7,500 years ago, when rising Mediterranean sea levels breached a land barrier and rapidly flooded a large inhabited freshwater lake. The event would have displaced enormous numbers of people in all directions, spreading a memory of catastrophic flooding into the founding populations of multiple cultures. This theory has scientific support and serious critics.
The third explanation is cultural transmission that we have not yet traced. Human populations moved around more than previously understood. Ideas traveled. Stories crossed land bridges and coastlines via trade and migration routes that archaeologists are still mapping. The specific parallel details might have spread through mechanisms that left no obvious historical record.