Little Sister Vent



Throughout Rapture there are numerous holes in the wall surrounded by metallic fixtures. These vents allow Little Sisters access to all areas of the city so they can collect valuable ADAM from corpses. The Little Sisters are the only thing small enough to fit into these vents and crawl through them, therefore they can use them as a means to safely move around the city without a Big Daddy.

Big Daddies are always awake and vigilant. When they do not have a Little Sister with them, they roam to the nearest vent and pound on its rim. The noise summons a Little Sister out. When the Little Sister is tired of or finished gathering ADAM, she goes back to the vent and the Big Daddy usually helps her up into it.

The design of the metallic plate, which includes stylized leaves and plant stems, insinuates that the vents may all lead - possibly through a pumping system - to Arcadia, transporting oxygen and carbon dioxide to and from them. Some areas of Rapture contain vents that are in disrepair with water flowing over or out of them. The Little Sisters were conditioned to use these vents by educational posters in the Little Wonders Educational Facility in Point Prometheus. However, the names of the vents were simplified to seem more innocent/friendly as they are nicknamed, 'Hidey Holes.'

BioShock
If the player uses Hypnotize Big Daddy or saves a Little Sister after taking down a Big Daddy, she will scurry back to the nearest vent and crawl away. On levels where Jack has already rescued or harvested every Little Sister, lone Big Daddies roam around and continue to pound on the vents, but no Little Sister comes out. They will show physical signs of aggravation and disappointment, then trudge, in vain, to the next vent.

BioShock 2
In BioShock 2 vents are one of the only locations that Subject Delta can directly interact with an adopted Little Sister. After approaching and interacting with a vent, the player is given the option to harvest or save the Little Sister. If she is saved, the little girl will climb up into the vent and disappear.

Throughout Rapture there are many vents which have been decorated as shrines by The Rapture Family. At these locations the Splicers hold services and offer themselves up to the Little Sisters to have their ADAM harvested.

Trivia

 * When Jack approaches a vent, in BioShock, a Little Sister's eyes can sometimes be seen peering out.
 * The above also occurs in BioShock 2. If the player looks into the first Little Sister Vent encountered in the game (on a landing of the staircase), the player should see Little Sister eyes bobbing, quickly falling down the vent.

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