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Cosima Niehaus

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Cosima Season 3
Biographical information
Full name: Cosima Niehaus
Birthplace: San Francisco, California, United States
Birthdate: March 9, 1984
Status: Alive
Age: 31
Residence: Dyad Institute, Toronto, Ontario, Canada
Minneapolis, Minnesota, USA (formerly)
Occupation: Evolutionary Development Biologist (formerly)[1]
Other information
Also known as: Cos (by Sarah)
Auntie Cosima (by Kira)
Gender: Female
Hair color: Brown
Eye color: Brown
Skin color: White
Height: 5'4"
Monitor: Delphine Cormier (formerly)
Emi (formerly)
Marital status: Single
Significant Other/s: Delphine Cormier (ex-girlfriend; in love with)
Shay Davydov (ex-girlfriend; it's complicated)
Emi (ex-girlfriend)
Family: The Niehauses (adoptive family)

Leda clones (sisters/genetic identicals)
Castor clones (genetic brothers)
Kendall Malone (sister/genetic template)
Kira Manning (genetic niece; via Sarah)
Siobhan Sadler (genetic niece; via Kendall)

Series information
Portrayed by: Tatiana Maslany
Season/s: 1, 2, 3, 4, 5
First appearance: "Instinct"
Latest appearance: "The Redesign of Natural Objects"
Appearance count: 39
"Right. I'm 324B21."
—Cosima after Delphine tells her her "tag number"[src]

Cosima Niehaus is a Ph.D student and a clone of American origin on Orphan Black. She, along with fellow clone Alison Hendrix first meet Sarah Manning whilst the later is under the guise of Beth Childs. The three clones decided to group together to form "Clone Club"[2], whats aim was to find their origin and where they came from. Cosima was previously involved in a romantic relationship with Delphine Cormier until they broke-up due to Cosima believing she could not trust her anymore. Cosima is currently ailed by a respiratory illness that is based in her ovaries and reproductive system what causes her to cough up blood.[3]


Early life

Cosima comes from San Francisco, California, and studied at UC Berkeley. She is currently completing her Ph.D in Experimental Evolutionary Developmental Biology at the University of Minnesota. She has been in a relationship with Emi, lead singer of the band Pythagoras and also her monitor at that time but broke up after moving to Minnesota, believing she cannot handle a long-distance relationship.[4]

Beth Childs managed to find her and another clone, Alison Hendrix, through a facial recognition program after Katja Obinger contacted Beth about three other clones in Europe. They had been looking after each other ever since. Meanwhile, the sick Katja, who wanted to see Cosima, whom she knew as a doctor, was asked to submit proof of the European clones' predicament to Beth. Prior to Beth's suicide, it seemed that Cosima constantly called her for updates.

Season 1

In "Natural Selection", after Sarah Manning assumed Beth's identity, Cosima still kept constantly calling Beth's phone.

In "Instinct", after Katja was killed in front of her, Sarah finally picked up. When Sarah, pretending to be Beth, informed her that the German was dead, they both panicked momentarily, finally realizing that Katja was telling the truth about someone wanting them dead. Cosima then advised Sarah to get rid of the body and get Katja's hair and blood samples. Later, while Sarah was at Felix's apartment, Cosima called and told her to get Katja's briefcase at the hotel where Katja was staying. When Cosima called Sarah back, Sarah had retrieved Katja's briefcase and frustratingly came clean. Cosima, in a moment of confusion, hung up. Sarah tracks down Alison, thinking she was the caller, but is later introduced to Cosima at Alison's house.

Cosima meets Sarah Manning in person.

In "Variation Under Nature", Cosima tried to explain their predicament calmly to Sarah and later stressed the importance of the briefcase to her. Alison, at first, doesn't believe that Beth committed suicide, but Cosima observed that Beth was "losing it." After Alison tells Sarah that they are all clones and are being killed off, Cosima remarks that she wanted to explain it more softly. Before Sarah left Alison's house, Cosima meets Felix Dawkins, Sarah's foster brother, and tells Sarah to bring her Katja's briefcase if she wants more answers. When the police discover Katja's body in rock quarry, mangled by a gravel crusher, Sarah, still posing as Beth, calls Cosima for help about keeping Katja's identity a secret. Sarah eventually meets up with Cosima at a local bar on the day she is set to return to Minneapolis for her studies.

"Don't worry, you get used to it."

Cosima tells Sarah how 6 months earlier, Katja contacted Beth explaining that her clones were being hunted in Europe. Cosima tells Sarah that she needs to keep pretending to be Beth so that they can learn more about who's killing them. She explains to Sarah that Katja's fingerprints will match Sarah's and that she must hinder the police's investigation into Katja's identity. Sarah finally gives Cosima the briefcase so she can study and analyze the samples inside. The next time Sarah calls her, Cosima has returned to Minnesota. Sarah tells her that she was able to stop the fingerprint results and that Katja's killer contacted Beth's partner Arthur Bell. Cosima tells Sarah to stick with Art, but Sarah tells her that she's on desk duty because she's useless as a cop. When she tells Cosima that she has to shoot with Art at the gun range, and she's never fired a gun before, Cosima arranges for Alison to teach Sarah.

In "Effects of External Conditions", Cosima is first seen when she is video chatting with Sarah and Felix. Cosima is examining the knife that Sarah got from Helena and trying to explain Helena's motivation for killing. Later, Cosima calls Sarah and tells her that Helena is connected to Maggie Chen, the woman that Beth shot. Cosima deduces that Beth shot her on purpose. Sarah tells Cosima about the police profile on Helena and Cosima explains that Helena is on a religious crusade to kill the clones because Helena believes them to be abominations.

She, Sarah and Alison often video chat, and Sarah often calls Cosima for help and keeps her in the loop of things. Cosima is the science-side of the clones, using her knowledge and resources to dig further into their creation and genetic makeup.

Upon her return to Minneapolis, Cosima immediately begins working on comparing the blood samples of her fellow clones, particularly to find out if they might have the same disease Katja had. She soon meets the charming French student, Delphine. Cosima is almost immediately suspicious of her, telling her fellow clones that she thinks new friend might be her monitor. Despite her suspicions, Cosima befriends Delphine, pretending to be monitoring her instead.

Cosima, however, finds herself very taken by her and, wanting to trust Delphine, makes a pass at her. Initially unsure of how to approach her, with Aldous Leekie's urging, Delphine begins a relationship with Cosima and unwittingly falls for her, as well. Delphine continues to report her discoveries in her room to Leekie when she finds out that Cosima's life may be in danger.


The Clone Club meets to discuss Rachel's offer.

When Sarah tells her that someone sold them out to Leekie, Cosima soon discovers Delphine's true identity and that she had in fact been spying on her for Leekie and confronts her about it. After she left in an attempt to avoid Delphine, she started coughing and soon discovered blood on her hands. When she left the terminal, she was stopped by Leekie in an attempt to make her sign a contract, which entailed her a job in Dyad Institute and freedom to study herself and the other clones. Cosima finally faces Delphine when she follows her all the way to Canada and the pair make amends. Cosima continues to investigate their genetic makeup and, with the help of Delphine, uncovers the portion in their genome which contain their tag numbers and their creators' patents on them. Cosima calls Sarah just when she was on the way to accept Rachel's offer to warn her about the patented genomes, and Sarah runs for it.

Season 2

Season 3

In the Season 3 premiere, Cosima is living in Felix's loft and appears to be healthier. She speaks to Kira about her dream (from the Season 2 finale) and her "coming back" to Kira. Their conversation is interrupted by Delphine, who tells Cosima that she is taking over some of Rachel's duties at Dyad, effectively putting her in charge. She also breaks up with Cosima, and tells her that she is keeping her promise to love and care for each Leda clone equally. She tasks Cosima with finding a cure for herself and her sisters, before tearfully leaving the loft. Later that day, Scott comes to perform a checkup. Cosima shows him Professor Duncan's key imbedded in his copy of The Island of Dr. Moreau while telling him to keep the information secret until they can both decipher the information.

In "Transitory Sacrifices of Crisis", Scott is still performing regular checkups on Cosima's condition and is surprised by her significantly improved test results. Both he and Cosima are unable to explain her sudden improved health though Cosima begins to explore potentially spiritual explanations. Back at Dyad, Cosima and Scott meet with Dr. Nealon. They discuss Rudy's escape from Marion Bowles' basement as well as the lost Leda genome. Dr. Nealon informs them of the origins of Project Castor and Leda as well as the impossibility of finding the original tissue donors, whose records were falsified and destroyed by both Susan and Ethan Duncan. Later, Cosima helps Sarah by researching the mythology of Castor, the warrior horsemen, thereby associating the Project Castor clones as, "the perfect ghost soldiers". She also tells Sarah to speak with Siobhan so that they can find Paul and ultimately Helena.

Personality and traits

Cosima is an eccentric, queer, tattooed geek girl with a scientific mind verging on genius. She's dependable, incredibly caring, brave, driven to find answers and, like Sarah, adaptable to extreme circumstances. She also tends to diverge on scientific topics and can talk relatively fast when she gets excited.

Physical appearance

Cosima usually wears her hair in intricate dreadlocks. In addition to her tattoo, Cosima also has a nose ring. According to Felix, Cosima has bigger breasts than Sarah and is apparently more attractive.


  • Her tag number, the number that identifies her among the clones, is 324b21.
  • In Effects of External Conditions, she is shown to be smoking marijuana. She later admits to Delphine that she only smokes this and never cigarettes in Variations Under Domestication.
  • She is shown to have a taste for wine as she was seen having a glass in a bar in Variation Under Nature and stealing two bottles from Leekie's reception in Variations Under Domestication.
  • Her laptop is covered with a laptop skin designed with multi-colored DNA strands and carbon rings.
  • The reason that Cosima wears glasses and her clones do not is due to the fact that her sight degenerated due to her environment and conditions. She just studies too much.[5]
  • Cosima was named after Orphan Black's own Science Consultant, Cosima Herter.[6]
  • In an interview, Tatiana states that the writers mentioned to her that Cosima was bisexual, though Tatiana feels that Cosima simply just loves people.[7] Despite this, Cosima refers to herself as a lesbian in Community of Dreadful Fear and Hate whilst making a speech as Alison.
  • The actress, Tatiana Maslany, who plays the clones, uses music to differentiate the clones. Her playlist for Cosima is electronica, including artists such as Diplo and Grimes. Maslany has described it as "beeps and boops kind of stuff."[8]
  • Cosima's DYAD Institute employment record shows her ID tag as 7274-7342-CS.[1]



Season 1 appearances
Natural Selection Instinct Variation Under Nature Effects of External Conditions Conditions of Existence
Variations Under Domestication Parts Developed in an Unusual Manner Entangled Bank Unconscious Selection Endless Forms Most Beautiful
Season 2 appearances
Nature Under Constraint and Vexed Governed by Sound Reason and True Religion Mingling Its Own Nature With It Governed As It Were By Chance Ipsa Scientia Potestas Est
To Hound Nature in Her Wanderings Knowledge of Causes, and Secret Motion of Things Variable and Full of Perturbation Things Which Have Never Yet Been Done By Means Which Have Never Yet Been Tried
Season 3 appearances
The Weight of This Combination Transitory Sacrifices of Crisis Formalized, Complex, and Costly Newer Elements of Our Defense Scarred by Many Past Frustrations
Certain Agony of the Battlefield Community of Dreadful Fear and Hate Ruthless in Purpose, and Insidious in Method Insolvent Phantom of Tomorrow History Yet to Be Written
Season 4 appearances
The Collapse of Nature Transgressive Border Crossing The Stigmata of Progress From Indistinct to Rational Control Human Raw Material
The Scandal of Altruism The Antisocialism of Sex The Redesign of Natural Objects The Mitigation of Competition From Dancing Mice to Psychopaths

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