In Fallout Shelter, Dwellers are your worker ants. You, the Queen, must protect the colony and secure its future by ensuring they scurry away at their jobs as efficiently as possible. Even laying dubious ant metaphors aside however, there is a more strange - and ethically dubious - side to maximising the efficient running of your Vault, and that's the practice of eugenics.
Here, we'll be explaining the best ways to keep on top of Dweller happiness, plus we'll explain Dweller SPECIALs, dweller breeding, and the best dweller placement.
How to get more Dwellers
The main way to get more Dwellers is through breeding them. Dwellers will sporadically turn up outside your Vault from the Wasteland, and we believe that's made more likely the more people you send out to explore, but this is a difficult mechanic to influence and an unwise one to rely on. Breeding, on the other hand, is a certainty, and a method which can allow the number of your Dwellers to grow exponentially.
Two Dwellers will decide to embark on a romantic snuggle if you place a male and a female together in the Living Quarters room. After a few minutes of small talk, cheesy pickup lines and awkward, musicless dancing, they'll run off to the back room and return soon after, the female now with child. It can take some time for the woman to give birth - normally around eight hours or so from our experience - and a similar amount of time again for the child to grow into an employable adult Dweller.
Also worth noting is the fact that pregnant Dwellers can continue work in their rooms as normal, and can be equipped with both outfits and weapons, but can't fight or tend to disasters. Instead, pregnant Dwellers will flee the room to avoid taking any damage, which means that whilst outfits can be useful, equipping pregnant Dwellers with weapons will be a waste. Children will similarly flee, but also can't be equipped with gear or do any work at all, so let them roam around freely until they mature.
Finally, be sure you have enough space for your Dwellers to be born, by building enough Living Quarters rooms in your Vault. Likewise, keep track of your resources - food and water in particular can take a hit if you're breeding heavily, so keep your production rooms populated and upgraded.
How to increase Dweller SPECIAL stats
As with increasing your Dweller count, there are two ways in which you can improve your Dwellers' SPECIALs: through training rooms, and through selective breeding.
There are seven training rooms - one for each of your Specials - which you can assign Dwellers to in order to increase their current stats. Leave them there and, over time, their correlating SPECIAL will increase.
Breeding is the more rewarding method of improving your Dwellers, as by carefully selecting parents you should be able to acquire Dwellers with specifically tuned SPECIALs. Parents with one high stat - such as Strength - will produce a child with high Strength too. It's as simple as that; combine parents with favourable, useful stats to cover any deficiencies you might have in your spread of Dwellers, or for targeting particular resources over time. After a while, when your engineered children have all grown up, Dwellers who arrive outside your vault with low stats can then simply be sent straight out to the Wasteland to gather resources - or simply to die, if you're particularly cold.
Where to place Dwellers in Fallout Shelter
Much like your character in Fallout 4, each Dweller has their own set of SPECIAL stats - Strength, Perception, Endurance, Charisma, Intelligence, Agility, and Luck - which dictate how they'll perform in a variety of situations, including how well they'll do in your Vault's various rooms.
You'll want to place Dwellers according to their strongest SPECIALs, particularly in the early and mid game. Once you have enough Dwellers to start sparing the less useful ones, you can opt to either train them up or, if you're feeling particularly brutal, send them out to the Wasteland. It'll most likely mean death for low-level and low-SPECIAL explorers - particularly if they're left unattended in the Wasteland overnight - but if managed correctly the extra experience, items, and bottle caps they'll return with make the added management worth it.
Other Fallout Shelter guides:
Looking for more guides on Fallout Shelter? Take a look at our main Fallout Shelter guide and tips page, our guide to room functions and room placement, advice on dwellers, SPECIALS, happiness and breeding, explainations of Legendary Characters, Pets, Weapons and other collectibles, how to unlock and use Mr Handy, plus how to earn Bottle Caps and Lunchboxes with Objectives, and our page on Quests, combat, and Daily Quests in Fallout Shelter, too.
How to increase Dweller happiness
Dweller happiness is predominantly governed by where you set them to work. Assigning a Dweller to the right room will increase their happiness over time - stick a Dweller with high Strength in the Power Generator room and they'll be chirpy as anything before you know it.
The other method is through mating. If you have a particularly grumpy pair of male and female Dwellers, pop them in the Living Quarters together and - as long as they're not related - the couple will cheer up plenty once there's another child on the way. Try to still keep pairing parents together with useful SPECIAL s, but if that's not possible you can always send the less useful kids off to scour the Wasteland once they grow up.