Why does Judaism believe in דולפנין Mermaids?

Rashi on Bekhorot 8a:1:1

The Dulfanin reproduce with people - if a person lies with one of them, they can produce offspring. ( ה"ג הדולפנין פרים ורבים מבני אדם - שאם בא אדם עליהם מתעברות הימנו )

Rashi on Bekhorot 8a:1:2

Sons of the sea - there are fish in the sea that are half in the form of a man and half in the form of a fish. Sirene in old French. ( בני ימא - דגים יש בים שחציין צורת אדם וחציין צורת דג ובלע"ז שריינ"א )

Ramban on Leviticus 11:10:1

In my view, however, “creature that creeps [sheretz]” includes the fish swimming in water, because the connotation of shritza is movement, and “any living creature” refers to the sea animals that walk on their feet like the beasts of the field. All of them have one law. The Midrash in Toras Kohanim, however, says: “‘Living’ — this refers to the beasts of the sea, ‘creature’ — this includes the mermaid.


  • The concept of a Mermaid seems similar to the Philistine false idol Dagon.
  • Why would a false mythological being be accepted as a real sea-creature by Rashi & Ramban?
  • Does Judaism still support Mermaids are real?
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    – Isaac Moses
    Mar 10, 2021 at 16:13

2 Answers 2


Contrary to popular belief, mermaids do not exist. The Gemara describes dolphins, which Rashi mistook as mermaids or read it that way in Worms. Similarly, what Christopher Columbus and the Spanish explorers thought were mermaids were actually manatees.

The Gemara states:[1]

Everything copulates front facing back, except for three species that copulate face-to-face: fish [dolphins], humans and snakes.

Also, there is a variant in the Gemara. It reads that "dolphins mate LIKE humans [kivnei adam], not "with humans" [bivnei adam]." Rashi substituted the "like" with "with."[2]

[1] See Bechoros 8a. The "people of the sea" who breed like humans are dolphins because dolphins breed like humans, they are actually not fish but mammals.

[2] I thank @Shalom in the comment section for bringing this to my attention.

  • 5
    The Gemara about "dolphins" has a variant text changing one character: dolphins mate LIKE humans [kivnei adam], not "with humans" [bivnei adam]. That's the straightforward way to read the Gemara, and in line with today's science. Rashi had the word "with", and most likely in his time and place most believed mermaids were real.
    – Shalom
    Feb 23, 2021 at 14:58
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    @TurkHill of course. I wouldn't say Rashi himself mistook the letter; it was likely in the text which he studied in Worms ... but somehow, somewhere along the lines it had gotten corrupted.
    – Shalom
    Feb 24, 2021 at 16:27
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    I would applaud this answer had Rashi not mentioned the Sirenes. With this, it is impossible to claim Rashi was misunderstood and spoke about dolphins. This also invalidates the other reading of the Gemmorah.
    – Al Berko
    Feb 27, 2021 at 19:43
  • 1
    @AlBerko Could you elaborate? Thanks.
    – Turk Hill
    Feb 27, 2021 at 21:24
  • 1
    @AlBerko where in this answer is it stated that Rashi was speaking about dolphins?
    – Baby Seal
    Mar 1, 2021 at 14:21

I dont think its forbidden to believe in something which youve never seen. Even if you were to show me Jewish sources which ascribe supernatural powers to mermaids, it likely wouldnt be an issue of avodah zarah as long as it isnt being worshipped (actively seeking its favor). Furthermore, the fact that it may have been a philistine deity does not mean it wasnt a real thing - see the cow in hinduism. Also, perhaps rashi and ramban dispute the claim that dagon was a mermaid.

  • Do you think "zather" exists?
    – Turk Hill
    Feb 24, 2021 at 19:09

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