Adult sil
Biographical information
Gender Female
Species The Species
Age 3 months (Actual age)
12 (in appearance)
23 (in appearance)
Status Deceased
Cause of Death Shot in the face
Killed by Preston Lennox
Family Unnamed son
Stephen Arden † (sex encounter)
Dream Male (mate in dream)
Abilities Strong animalistic instinct of survival and procreation, Transform to alien form, rapid regeneration, Sense genetic flaws in potential mates, breast-tentacles, long tongue is tipped with sharp spines, Incredible ability to assimilate knowledge just by touch, Incredible intellect, and able to hang upside down on celings
Played by Natasha Henstridge (Adult Sil)
Michelle Williams (Young Sil)
Appearances Species

Sil was a alien-human hybrid created by the Search for Extraterrestrial Intelligence program.

Known as test subject S1L ("Sil"), she was formed from the fertilization of a human ovum with alien DNA. Sil was raised and monitored in a controlled lab environment until the scientists studying her attempted to kill her. Escaping her confines, she broke out into Los Angeles where she evolved and fell to her alien instinct to find a suitable male and mate; becoming an intelligent but hyper-sexual predator.

She is the main character and antagonist of the film Species.


Sil clearly had human-like emotions, including, to some extent, a desire to be loved and accepted, as well as having an emotional attachment towards her son.


Young teen Sil

When she kills, she does so out of instinct, in an effort to defend herself, or to preserve her masquerade which she has to maintain in order to survive.

Giger-Sil sculpture3

Sil in alien form

Biology and AbilitiesEdit

Her alien form is chitinous and reptilian, but still humanoid in its appearance. Her "hair" is a mass of prehensile tentacles which are slicked back behind her head when not "active".

She possesses two sets of teeth with the internal set being razor sharp. Her tongue is tipped with sharp spines or barbs and is her primary defense mechanism (or weapon) when with a potential mate. When threatened, she can impale her aggressor with her tongue, usually during kissing, by inserting her tongue into the victim's mouth from within which she can stab into the victim's skull or out the back of their head, resulting in her infamous "kiss of death".

Her breasts, rather than storing fat or mammary glands like a human female's, instead store additional prehensile tentacles which can emerge from her "nipples". She can use her breast-tentacles as weapons (wrapping one around her victim while the other penetrates their mouth and chokes/stabs them to death) but they can also be used in her species' mating rituals (as shown in the second film).

Sil possesses sharp spines that run up her back, she can retract and extend these at will.

While capable of conceiving children in her pubic region like a typical human female, Sil is shown to give birth via her chest cavity, which splits and opens to allow a fully-grown (or still-developing) infant to emerge from her.

Sil also possesses the ability to rapidly regenerate from any injury, from a broken scapula to a missing limb. However, she appears incapable of regeneration if her body is destroyed beyond the capacity for regeneration, such as being burned to death.

According to the third film, Sil is also disease-free, possibly boasting an immune system that is superior to a human's.


After the Search for Extraterrestrial Intelligence project receives a pair of messages from outer space, the second containing a DNA sequence along with directions on how to mix it with Human DNA, the project's scientists attempted to put the sequence to use, injecting the DNA into one hundred human ovum. Of which, seven divided; with four of those seven dying out to leave three active hybrid eggs. Two of those three were frozen for storage and the third, designated S1L, was allowed to grow and mature.


Sil births after one month.

Within 2 hours, the egg began to diffuse and multiply. Within one day it began to gain form; achieving a fetus within 2 days. By 1 week Sil was a full fetus and was birthed as a human child in one month from her conceptions.

Kept within a quarantine chamber for observation, after three months, Sil began experiencing dreams that caused her erratic spasms while sleeping. Unnerved, the scientists decide to terminate her with cyanide gas. However, she escapes from facility and manages to hitchhike on a train where she has her first dream of performing a mating ritual in her natural form. Waking up just as a drifter was about to assail her, she fends him off, bending him in half on instinct. After she loots his sack for clothes, she stays on the train to Brigham City where she gets off as the train stops.

Sil enters a convenience store and observes customers as they pay for items. But, as she is unable to buy food, she attempts to, but fails to steal any food. Instead, she manages to steal some luggage and board a passenger train.

Exploring the luggage, Sil finds and watches a portable television set. Finding a bar on the train, she rips open the cashier draw and takes the money found within. Still exploring the train, she discovers the kitchen and begins "acquiring" various items from scrubbing brushes to bananas.

異種1.mkv 1455639753

Sil transforms and becomes a cocoon.

While sleeping, Sil has another dream of an alien train running her down. When she wakes up, tentacles start emerging from underneath her skin and mass to form an organic cocoon around her.


Sil emerges from the cocoon

While transforming within the cocoon, Sil kills train conductor Angela Cardoza before emerging as a blonde, twenty-something adult woman.

Acquiring Cardoza's clothing, Sil disembarks at Los Angeles. Fully grown but still innocent, she buys a wedding dress to wear and, while interacting with the cashier, learns some words. While walking through the city, she encounters many children and pregnant women.

Renting a room at a motel in Hollywood, she discovers and watches more television before changing into other clothes she had bought and seeking out a club to meet a man.

While initially meeting random guy, he is quickly "taken" by another woman. Adopting the woman's policy of "whatever it takes", Sil kills the woman by ripping out her spine while in the bathroom. Adapting her clothing to match yet other woman in the club and manages to convince another man, Robbie Llywelyn, to take her to his house; watching and learning how to drive as he takes her. While on the verge of being seduced, she senses that Robbie was a diabetic, rejects him and attempts to leave. However, he refuses her request and attempts to dominate her, resulting in her stabbing her tongue through the back of his head when he forces her to make out.

Avoiding the motel after discovering the S.E.T.I. tracker team at swarming the area, she has a further dream of mating with a male alien underwater.

異種1.mkv 1455640942

Sil kills a potential mate by forcing one of the tentacles into his mouth.

Leaving the car after running out of fuel, Sil is hit by a car but is saved and taken to a hospital by a good Samaritan, John F. Carey. After consciously healing herself, she convinces John to take her to his house where, discovering a hot tub, she undresses in an attempt to seduce him in the water so that they may copulate. Sil kisses him but her attempt is interrupted by Dr. Laura Baker and Preston Lennox. While attempting to keep John from alerting them, she rapidly transforms into her natural form and attempts to restrain him with her tentacles, forcing one of the tentacles into his mouth to keep him from screaming. This inadvertently kills him.

Escaping the trackers, she reverts back to her human disguise but she has no time to reclaim her clothes forcing her to flee into a forest naked and, acquiring a car and clothes from a woman named Marie Keegan she kidnaps, uses lip reading to learn the trackers' next move and follows them to their motel and rooms.

After setting up a rouse, Sil lures the team into a chase and purposely crashes the car, using Marie's body to act as a decoy. Managing to convince the team's management of her "death," she changes her hair color and stalks the team members as they celebrate at their hotel. As far as anyone is concerned, her alias is now Nicole.

Sil finished copulating with Dr. Stephen Arden and became pregnant

Following Dr. Baker and Lennox to their room, Sil eavesdrops on their lovemaking and becomes aroused. When Dr. Stephen Arden walks in on her eavesdropping, he asks her who she is and she tells him that she stole the key. Sensing that there is nothing wrong with him and that he’s a suitable mate, Sil tells Arden that she saw him downstairs in the bar and begins to immediately undresses in order to seduce him into sex. She begins to kiss the hesitant Arden and tells him that she just wants to be with him, Arden finally gives in and returns her kisses. Sil begins to remove his shirt which Arden does and brings her in closer with a embrace in which Sil aggressively pushes him onto the bed. Mounting the undressing Arden, she begins to kiss him once more and ignores his question about protection. Once they are fully naked, Sil begins to mate with Arden with her on top. As Sil mates with Arden, his teammate Dan Smithson, senses that Sil is still and alive and hears Sil and Arden through the door. After he tells the rest of the team, Sil succeeds in getting pregnant when Arden has reached orgasm and deposited his seed into her. Staying on top of Arden while he admires the session, Sil remains quiet waiting for his seed to reach her womb. Sil suddenly smiles as she can feel their child growing inside of her. When he asks her what it’s going on she replies“ It’s started” while Arden asks “what started.” Sil happily tells him “life” which causes Arden to give her condescending laugh and explaination. When he doesn’t believe her Sil takes his hand and places it on her belly so he can feel their child. Sil remorselessly kills Arden after he feels their child developing and realizing who she is as the rest of the team discover her being still alive and chase her into the sewer. There, she manages to kill Xavier Fitch before being forced to hide to have her baby.

Species birth pic

Sil giving birth by opening her chest cavity

The remaining team follows Sil into an oil-filled cave and kills the baby. Enraged, Sil attempts to kill Lennox but is shot into the oil lake which was set aflame by the baby's corpse. Attempting to escape the flames, she is shot by Lennox point blank with a shotgun and thrown back into the fire, successfully killing her.

The last scene shows one of Sil's severed tentacles was chewed on by a rat; it starts to mutate into a vicious beast and attacks another rat.

Species NovelizationEdit

Killed VictimsEdit

  • Unnamed homeless man (head snapped)
  • Angela Cardoza (head snapped when she discovers Sil's cocoon)
  • Unnamed woman (backbone snapped due to Sil's jealousy)
  • Robbie Llywelyn (punctured his skull with her tongue after Sil senses that he is diabetic and he tries to rape her)
  • John F. Carey (forcing one of her tentacles into his mouth after he refuses to mate with Sil)
  • Marie Keegan (burned as a stand-in for Sil's own body due to Sil trying to fake her death by destroying the car)
  • Unnamed hotel housekeeper (attacked due to Sil wanting the key of Stephen's room)
  • Stephen Arden (attacked after he copulates with Sil and realizes who she is)
  • Unnamed man (attacked during Sil's escape to the sewer)
  • Xavier Fitch (attacked when the team hunts Sil)


Dr. Stephen ArdenEdit


Dr. Stephen Arden

"What about protection?"
—Stephen to Sil when Sil pounces on him, naked and they have sex.

Dr. Stephen Arden was a sexual partner of Sil and the biological father of her son. Sil doesn't really have a relationship with him. Sil only needs human sperm to produce offspring. After being impregnated by Stephen, she killed him shortly.

Originally, Stephen was an anthropologist member of a team of scientists and specialists led by SETI (Search for Extra Terrestrial Intelligence) head honcho Xavier, which tracks and destroys Sil. 

When the team celebrates their apparent victory of the death of Sil (In fact, Sil is still alive), Sil stalks them in their hotel. Sil takes an attraction to Preston Lennox. Following Dr. Baker and Lennox to their room, Sil eavesdrops on their lovemaking and becomes aroused. When Stephen walks in on her eavesdropping, she immediately undresses in order to seduce him into sex. Sil succeeds in seducing him and they copulate, ending in him impreganting her. Sil kills Stephen shortly after he does indeed feel something in Sil's womb and recognizes who she is.

Sil's SonEdit

Sil Baby

Sil's son

Sil's son is the only child of Sil with Dr. Stephen Arden.

Less than an hour after conception, Sil gives birth to her son in an underground cave and then leaves him alone for a while to protect him from the rest of the team sent to kill them. However, he demonstrates that he has a rapid rate of growth, already appearing as a young child. Just as he was going to attack Dan, he is killed by being set on fire and thrown into a pit of oil.

Behind the ScenesEdit

The animatronic puppet used in the film had a fully articulated head that could turn, tilt, jaw opens and like all good nasty aliens she has two sets of teeth to better rip your face off with. A remote control was rigged to control her two sets of eye lids, eye direction and mouth. Her hair/tentacles could be manipulated in nearly any direction via a wire control.


  • "I felt it!"
  • "It's started!"
  • "Life!"
  • "Don't you believe me? Feel!"
  • "Smells nice. Can I try some?"
  • "Does it work on your boyfriend?"
  • "Don't go. Please. I want a baby."
  • "I saw you downstairs, but you were with all those people."
  • "It's not too soon for us to be together."
  • "I'm sorry."
  • "Yes."
  • "You just don’t know it."


  • Unfamiliar with eating a banana, Sil attempted to eat the fruit, skin and all.
  • Sil was named after her ovum ID number, S1L.
  • In Sil's dream, the male alien has a "pony tail" tentacle that wraps around them until it's facing her. She then willingly lets it penetrate and enter her chest.
  • The breast-tentacle cut off by Lennox is later seen being eaten by a rat. After which, the alien DNA transforms the rat itself into a hybrid as it attacks another rat.
  • Sil's alien form is also capable of holding its breath underwater for an extended period.
  • Sil's "Kiss of Death", in which she penetrates her victim's skull with her tongue during a kiss, is shown in each of the franchise's films at least once.
  • Although a primary character in the first film, Sil still has some influence in the later films, as she is mentioned in the second and third films.
  • Sil is the first known, female hybrid to conceive and have a hybrid child (with Anne being the second, Eve being third and Miranda being the fourth, though never being shown delivering).
  • Sil, in her alien form, is voiced by Frank Welker, who's been known to voice other characters in his career, such as Megatron and several of the Transformers of Transformers, Scooby-Doo in all of his incarnations, etc.
  • The way Sil gives birth is similar to the Xenomorph births from the Aliens movies. While the Xenomorphs kill their human hosts upon being born, Sil's baby didn't kill her.
  • Sil is the only protagonist who didn't encounter another member of her species. While Eve interacted with Patrick, Sara with her siblings and mate and Miranda with other hybrids created by Forbes.


Human FormEdit

Alien FormEdit

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