Was Jonah Swallowed By A Sea Monster?

You’ve probably heard the story of Jonah – the prophet who was swallowed by a whale while at sea. But, was it really a whale? Some translations describe it as a “sea monster.” In this article, we’ll delve into the origins of this intriguing tale and explore why the creature that swallowed Jonah may have been imagined as a sea monster in its ancient context.

The Hebrew Description: Dag Gadol

The story of Jonah is found in the Hebrew Bible, where the creature is referred to as a “dag gadol.” “Dag” means fish, and “gadol” means large or great, so most English translations render it as a “large fish.” However, it’s important to note that the ancient Hebrew language did not have a separate word for “whale.”

The Greek Translation: Kêtei Megalô

When the Hebrew Bible was translated into Greek, known as the Septuagint, the Greek translators faced an interesting choice. Typically, Greek used icthus for fish and phallaina for spouting whales. However, the translators opted for neither of these words. Instead, they translated dag gadol or “great fish” as kêtei megalô in Greek. Megalos, as you can probably guess, means great or large.

However, the Hebrew “dag” meaning fish became ketos in Greek, a term that could refer to any large sea creature, including fish or whales. Furthermore, “ketos” was also used to describe mythical sea monsters, such as Leviathan or those from Greek mythology. In the ancient world, the categories of big fish, whales, and sea monsters overlapped considerably.

To illustrate this, one of the most famous ancient ketos had a name: Porphyrios. This ketos was a whale that terrorized sailors by sinking ships off the coast of Constantinople for 50 years. Emperor Justinian even attempted to capture it but lacked any means to do so. Eventually, Porphyrios wound up dead on the shore.

Whales as Mythological Beasts

Whales were not well understood in the ancient world, leading to mythological interpretations. There is no surviving ancient artistic depiction that accurately resembles a whale. Instead, whales were depicted with snaky bodies, scales, horns, or tusks, blurring the line between nature and myth.

Sometimes “ketos” were portrayed as fish-like, while at other times, they took on the appearance of dragon-like sea monsters. The ambiguity surrounding whales in the ancient world is evident in various artistic representations.

Krater from Pithekoussai depicting a fish like ketos swallowing a man (red highlight added)
The “Ketos of Troy,” Caeretan hydria, ca. 520-510 B.C
Ritual Water Jar (loutrophoros) with Perseus Battling the Sea Monster Ketos Greek made in Apulia South Italy 340-330 BCE Terracotta. Photo: Mary Harrsch

Similarities to Ancient Sea Monster Myths

The story of Jonah shares intriguing similarities with other ancient sea monster myths. Jonah set out from a town called Joppa before being swallowed by the whale. In Greek legend, Perseus also set out from Joppa to rescue Andromeda from a sea monster. Josephus described Joppa as perilous to ships and sailors, possibly serving as inspiration for these sea monster myths.

 Now Joppa is not naturally a haven, for it ends in a rough shore, where all the rest of it is straight, but the two ends bend towards each other, where there are deep precipices, and great stones that jut out into the sea, and where the chains wherewith Andromeda was bound have left their footsteps, which attest to the antiquity of that fable. But the north wind opposes and beats upon the shore, and dashes mighty waves against the rocks which receive them, and renders the haven more dangerous than the country they had deserted.

Flavius Josephus, The Wars of the Jews (419), William Whiston, A.M., Ed.

Furthermore, the Greek historian Pliny the Elder claimed that the skeleton of Andromeda’s sea monster was transported from Joppa to Rome. One scholar even suggests that the remains of a whale found in Joppa may have been interpreted as both Andromeda’s sea monster and Jonah’s sea creature.

The skeleton of the monster to which Andromeda in the story was exposed was brought by Marcus Scaurusb from the town of Jaffa in Judaea and shown at Rome among the rest of the marvels during his aedileship; it was 40 ft. long, the height of the ribs exceeding the elephants of India, and the spine being 1 ft. 6 inches thick.

Pliny, Natural History book 9

Finally, Jonah wasn’t the only person swallowed by a ketos in ancient history. The Greek hero, Herakles, was also said to have been swallowed by a ketos. He is depicted as entering the mouth of a ketos in this 4th century art work, in order to kill the beast from the inside out.

Herakles and the sea monster. Red Figure Column-crater, 4th Century

This legend is also recounted in Lycophron’s Alexandra (3rd century BCE):

“Begotten in three nights, that lion whom
The jaws of Triton’s sharp-fanged hound consumed”

There is a popular misconception that Lycophron actually has Herakles in the belly of the Ketos for three nights, which would be a very interesting parallel to the Jonah story. However, this is a misunderstanding of the line “gegotten in three nights” which harks back to medieval comments on the text. The three nights phrase really refers to the circumstances of Herakles’ birth; the night when Zeus came to Alkmene disguised as her husband and tripled the length of the night so that he could continue having sex with her for longer (Diodoros 4.9.2, ps-Apollodoros 2.4.8).1Thank you to KiwiHellenist on reddit for pointing me to this fact. Regardless, there was an ancient tradition that Herakles was swallowed by a ketos.


The idea that ancient people believed Jonah was swallowed by a sea monster is not far-fetched. In the ancient world, the categories of big fish, whales, and sea monsters overlapped significantly. Whales were not well understood and often took on mythological qualities. Therefore, it’s entirely plausible that the creature in Jonah’s story was a whale, but the ancient audience’s understanding blurred the line between nature and myth. The term “ketos” used in the Greek translation captures this ambiguity perfectly. So, perhaps Jonah was swallowed by a sea monster after all, a creature that for ancient people blurred the line between reality and myth.

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    Thank you to KiwiHellenist on reddit for pointing me to this fact.

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