Does a Simulacrum need to Eat, Sleep, Drink, or Breathe?

Question

So I am looking for some insights into some specificities of a Simulacrum. I have a vague understanding of how the D&D rules interact with Creature types (which is that they are rarely important). So does the Simulacrum being a construct mean it no longer needs the same maintenance as the Humanoid or Beast it copies? Or would I now need to double my ration stocks to maintain the Simulacrum's prolonged existence?

Simulacrum says this (emphasis mine)

You shape an illusory duplicate of one beast or humanoid that is within range for the entire casting time of the spell. The duplicate is a creature, partially real and formed from ice or snow, and it can take actions and otherwise be affected as a normal creature. It appears to be the same as the original, but it has half the creature's hit point maximum and is formed without any equipment. Otherwise, the illusion uses all the statistics of the creature it duplicates, except that it is a construct.

The simulacrum is friendly to you and creatures you designate. It obeys your spoken commands, moving and acting in accordance with your wishes and acting on your turn in combat. The simulacrum lacks the ability to learn or become more powerful, so it never increases its level or other abilities, nor can it regain expended spell slots.

If the simulacrum is damaged, you can repair it in an alchemical laboratory, using rare herbs and minerals worth 100 gp per hit point it regains. The simulacrum lasts until it drops to 0 hit points, at which point it reverts to snow and melts instantly.

If you cast this spell again, any duplicate you created with this spell is instantly destroyed.

In my head it seems like the Simulacrum would need the same maintenance as the creature that's being duplicated. As it makes no special additive to the Simulacrum save that it is now a Construct and is unable to regain HP except through a specified process. Would I be correct in thinking this or is there something I could be missing?

Answer 1

Yes, if the original creature needs to eat, drink, breathe and sleep

The creature types in 5e do not have automatic attached rules. They only act as a label that allows other game elements like spells or abilities that name them to interact with them, MM p. 6:

TYPE A monster's type speaks to its fundamental nature. Certain spells, magic items, class features, and other effects in the game interact in special ways with creatures of a particular type. (...) The game includes the following monster types, which have no rules of their own.

Therefore, there is no general rule that all constructs do not need to eat, drink, breathe or sleep. In the absence of this, the creature will need to do all these things.

The description of each construct must call out what is true or not true for it. Compare this to other constructs, like for example Animated Object, which has the following text in its lore write up:

Constructed Nature. An animated object doesn't require air, food, drink, or sleep.

Simulacrum copies a creature, so it will copy all its attributes. I am not aware of any humanoids or beasts that have a similar exception, but if there was one, then that simulacrum would not need to eat, drink, breathe or sleep.

Answer 2

You will have to decide

Several other answers here offer an unequivocal yes, and if that works for you, then question answered.

Simulacrum is challenging

I would like to offer a more nuanced view. The simulacrum spell is in some ways problematic, as evidenced by the many questions about simulacra here on rpg.se. You asked whether a simulacra eats, drinks, sleeps, or breathes, and that is a worthy question, but it is but one of many you are faced with when dealing with simulacra.

Some challenges you face are more rules-based in nature; for instance, a simulacra being able to cast simulacrum or wish presents questions that need to be answered.

Some challenges are more of narrative basis; for instance, how does a simulacrum behave? In most cases it probably knows it's a simulacra, perhaps that affects its outlook.

Still other challenges might involve game play; for instance, a simulacra could basically double the characters in play for a particular player, potentially slowing the game down, and giving one player more to do at the expense of other players.

Arguments for yes

As other answers here provide, a simple answer is yes, a simulacrum eats, drinks, sleeps, and breathes.

After all, it is a creature, and creatures need to eat, drink, sleep, and breathe; and the spell doesn't say it doesn't have to do these things, so it must.

Furthermore, it has all the statistics of the creature it duplicates, except that it is a construct.

Arguments for no

The simulacra in addition to being described as a creature is also described as an "illusory duplicate", "partially real", and is referred to as "the illusion". Further, the school of the spell is Illusion.

It does not seem completely unreasonable that an illusion perhaps can eat, drink, sleep, and breathe, but it does not have to do those things. While it is a creature, it is also an illusion.

As an illusion it is not completely unreasonable to argue it is sustained by the magic that makes it, not by biology; therefore a simulacrum does not have to eat, drink, sleep, or breathe.

What about the "yes" arguments?

First of all, there are counter-examples of spells that create creatures that do not say they need to breathe but it seems reasonable that they don't breathe. As an example, the animate objects spell creates creatures from objects, and does not describe breathing, for or against, but whether an animated coin is breathing seems not decided or described by the spell.

An example of a creature that probably doesn't need to eat, drink, sleep, or breathe is the animated armor described in the Basic Rules. At a minimum, it seems nonsensical that the armor would need to eat and drink to sustain itself.

Don't get me wrong, I am not so much arguing for no, or attempting to argue against yes, as to argue that within the rules either yes or no is not entirely clear-cut.

Making it work for your game

The player casting simulacrum and the DM will need to work together to decide how the spell works in their game. It's a good idea to discuss these things out of session, so that session time is not used up.

The rules do not specifically say whether or not the simulacrum eats, drinks, sleeps, and breathes; therefore, you will have to decide.

Answer 3

Yes

The Simulacrum is a creature and creatures need to do all that unless there is a specific rule that says they don’t. There is no such rule in the spell or in the description of constructs.

Answer 4

No

formed from ice or snow

There is no way for it to biochemically produce energy from food, thus also breathing is pointless. It seems to be fully sustained by the magic creating it.

wrt sleeping, seems more open for negotiation. From description though it doesn't sound as a sentient being with free will. More like a computer with your skills as a pre-installed function. If it was me, I'd go with no need to sleep.

It's interesting though whether it's ability to focus without being distracted is inherited by the spell target.