Iara, also spelled Uiara, Yara or Hiara (Portuguese pronunciation: [iˈjaɾɐ], [iˈaɾɐ], [ˈjaɾɐ], [wiˈjaɾɐ], [ujˈjaɾɐ]) or Mãe das Águas ([ˈmɐ̃j dɐz ˈaɡwɐs], "mother of the waters"), is a figure from Brazilian mythology based on Tupi and Guaraní mythology. The word derives from Nheengatu iiyara = ií ("water") + yara ("lord; lady").^[1] Depending on the oral tradition and the context of the story,^[2] she can be seen either as a water nymph, a siren, or a beautiful mermaid that lives in the Amazon River.

According to oral tales, Iara is a beautiful young woman sometimes described as having green hair, light brown or copper-colored skin (like that of an Indigenous person from Brazil or of a caboclo), and brown eyes with a tail similar to a freshwater river dolphin, manatee, or fish (the Tupi word y did not have a distinct meaning, being used in general for any riverine or freshwater lacustrine place) who sits on a rock by the river combing her hair or dozing under the sun. When she felt a man around, she would start to sing gently to lure him. Once under the spell of the Iara, a man would leave anything to live with her underwater forever^[3] due to the fact that she was pretty and would cater for all the needs of her lover for the rest of his life. Other versions indicate that she slew the men or drowned them.

According to Brazilian folklore, Iara was a beautiful young Indigenous woman in a tribe of patriarchal customs who developed a talent for warfare and gained admiration from all of her tribe and respect from her father,^[4] the chief of the tribe, but aroused the envy of her brothers who decided to murder her during the night. The legend says Iara knew how to defend herself from her brothers' attacks and accidentally killed them.^[5] Discovered by her father, she took refuge in the woods but was captured and punished for the murders of her brothers by being drowned in the river. Other versions claim they killed her and dumped her body in the river and blamed the night goddess, Jaci, for her disappearance.^[3] Turned into a mermaid upon being saved by nearby fish on the night of a full moon or by Jaci in some versions, she decided to take revenge on all men by seducing them and drowning them in the river. According to some folkloric accounts, those who survive end up going crazy^[6] or survive with teeth marks on their neck.^[7]

It is often claimed that, until the 18th century, the Iara legend did not pertain to the image of a seductive, docile river mermaid. Instead, it was originally about an aggressive and monstrous river merman known as Ipupiara ("freshwater monster"^[8]) who would readily devour fishermen.

Iara is immortal, but many of her lovers age and die, so she is condemned to live most of eternity alone.

The legend of the Iara was one of the usual explanations for the disappearance of those who ventured alone into the jungle.

The Iara is similar to several other folkloric female figures from other regions of Latin America such as the Colombian La Patasola and the Tunda. They all function as sirens leading men to their deaths, though the Patasola and Tunda are specifically forest spirits and the Tunda does not target only men and can treat the people it kidnaps nicely.

Andrew Lang wrote an adaptation of the legend of Yara in The Brown Fairy Book.^[9]

American naturalist Herbert Huntingdon Smith recorded a version of the legend of Yara, which he titled Oiará, The Water-Maidens.^[10]

Iara (or Yara) is a very popular female name in Brazil.

In the film version of the novel Macunaíma (1969), the eponymous protagonist meets his death at the hands of an Iara. He embraces her eagerly and sees too late the blow hole in the back of her neck that gives her away as the creature she is and not the beautiful woman he mistook her for.

In 2021 Brazilian supernatural TV series, Invisible City, the protagonist meets an Iara but survives her drowning attempts. She tells him that she became an Iara after her lover killed and drowned her in a river, but she was resurrected.

In the 2021 DC Comics' Wonder Girl comic book starring the future Brazilian Wonder Woman, Yara Flor, Iara was a great Brazilian warrior who was later transformed into a mermaid-like divine being as the protector of the sacred waters. It was she who bestowed on Yara Flor her characteristic weapon of power, the Golden Boleadoras.^[11]

Iara appears in AdventureQuest Worlds. It was mentioned that Iara was knocked off the cliff into the river during a family scuffle and was turned into a mermaid by nature itself.

In Love, Death & Robots season 3 (2022), episode 9 "Jibaro", a deaf warrior meets an Iara who lures his comrades with her screams, causing them to enter a dancing frenzy, rushing to her to ultimately drown in the lake.

Iara is a minor antagonist in the TV series adaptation of Beastmaster, presenting as a siren who appears as a beautiful woman but it’s only an illusion as she is really a water snake. She always kills the warriors she loves and she spends her story arcs trying to make Dar her latest love/victim.

• List of legendary creatures by type#Water

• Figueira, Gastón (1942). "Mythology of the Amazon Country". Books Abroad. 16 (1): 8–12. doi:10.2307/40082369. JSTOR 40082369.
• Macedo, Tarcízio; Filho, Otacílio (May–August 2015). "[Dos rios à tela de cristal líquido: o retorno do mito e a arquitetura da cultura convergente em League of Legends]" [From the rivers to the LCD: The return of the myth and the architecture of convergence culture in League of Legends]. Fronteiras – estudos midiáticos (in Portuguese). 17 (2): 231–247. doi:10.4013/fem.2015.172.10. http://revistas.unisinos.br/index.php/fronteiras/article/view/fem.2015.172.10
• Sá, Lúcia, Maria Ignez França, and Lemos, Rafaella. "Macunaíma (1928)." In Literatura Da Floresta: Textos Amazônicos E Cultura Latino-americana, 79-120. Rio De Janeiro: SciELO – EDUERJ, 2004. ISBN 978-85-7511-442-1