Learn Hardcore Russian: Рядом обезьяна внимательно смотрит на людей и как будто ждёт, когда ей помашут рукой. - Nearby a monkey looks attentively at people and seems to be waiting for them to wave to her.

The есть is understood and almost always dropped in the present.
So Рядом обезьяна… is a perfectly normal way to say “Nearby, (there is) a monkey…”

Why is the word order Рядом обезьяна and not Обезьяна рядом?

Both are grammatical, but the emphasis is slightly different.

Рядом обезьяна внимательно смотрит…
Literally: “Nearby, a monkey is carefully looking…”
→ Focus on the location first (“nearby”), then introduce the monkey.
Обезьяна рядом внимательно смотрит…
Literally: “The monkey, (which is) nearby, is carefully looking…”
→ Focus on the monkey first, and “nearby” feels more like an extra detail.

In narrative description, starting with Рядом is a common way to add a new element to the scene: “Nearby, (there’s) a monkey that is looking…”

What exactly does рядом mean here, and why don’t we say рядом с something?

Рядом is an adverb meaning “nearby / close by / next to.” There are two common patterns:

Рядом by itself:
- Рядом обезьяна. – “There’s a monkey nearby.”
  This just states that something is close to the current reference point (speaker, place in the story, etc.).
Рядом с + instrumental:
- Рядом с нами сидит обезьяна. – “A monkey is sitting next to us.”
- Рядом с клеткой стоит мальчик. – “A boy is standing next to the cage.”

In your sentence, the context is already clear enough, so Russian just uses bare рядом: it’s “nearby (here in the scene)” without specifying “with what.”

Why is людей in that form? Which case is it, and why is it used after смотреть на?

Людей is the accusative plural of люди (“people”). The noun человек / люди declines irregularly:

Nom. pl.: люди
Acc. pl.: людей (same form as gen. pl.)

The verb смотреть (“to look”) with the preposition на (“at / to”) requires the accusative:

смотреть на людей – “to look at people”
смотреть на море – “to look at the sea”
смотреть на часы – “to look at the clock”

So людей is accusative plural after на.

Could we say смотрит людей without на?

No, not in this meaning.

смотреть на кого/что = “to look at someone/something” (direction of gaze)
смотреть кого/что without на is rare and sounds either:
- informal/colloquial in some specific phrases, or
- like “to watch (a film, a show)” — смотреть фильм, смотреть матч

For “looks at people,” you must say смотрит на людей.
Without на, смотреть людей would sound wrong or at least very unnatural in standard Russian in this context.

Why is ей used instead of её in когда ей помашут рукой?

Ей and её are different cases:

ей – dative (to her, for her)
её – genitive/accusative (her)

The verb phrase here is помахать (кому?) рукой – literally “to wave a hand to whom?” That “to whom” is dative:

помахать ей рукой – “to wave (one’s) hand to her”
помахать мне рукой – “to wave to me”
помахать детям рукой – “to wave to the children”

So ей is dative: “when (someone) waves a hand to her.”

Who is the subject of помашут in когда ей помашут рукой? There is no noun like “people” before it.

Russian often uses an indefinite plural verb form where English would say “someone”:

Стучат в дверь. – “Someone is knocking at the door.”
Говорят, что завтра будет дождь. – “They say / People say that it’ll rain tomorrow.”

Here помашут is 3rd person plural future, but the subject is indefinite: “someone (the people around) will wave to her.”

So когда ей помашут рукой = “when (someone) waves to her with a hand.”
The “someone” is understood from context and doesn’t need to be said explicitly.

Why is помашут (perfective future) used instead of something like машут?

The aspect and tense here are important:

махать рукой – imperfective: to wave (repeatedly/in general)
- present: машут рукой – “(they) are waving / (they) wave”
помахать рукой – perfective: to wave a bit / one (short) instance of waving
- future: помашут рукой – “(they) will wave (for a moment)”

In ждёт, когда ей помашут рукой, the monkey is waiting for a single future event: the moment when someone will (finally) wave to her. Russian normally uses the perfective future for a specific, completed future action in such “when”-clauses:

Он ждёт, когда начнётся концерт. – “He is waiting for the concert to start.”
Она ждёт, когда ей позвонят. – “She is waiting for someone to call her.”

So помашут (perfective future) fits the idea “when they (finally) wave (once / for a bit).”
машут would describe an ongoing or habitual action, which doesn’t fit with ждёт, когда… in this context.

Why is рукой in the instrumental case and not руку?

The expression is махать / помахать рукой – literally “to wave with (one’s) hand.” The thing used as an instrument or means of the action is put in the instrumental case:

писать ручкой – “to write with a pen”
есть ложкой – “to eat with a spoon”
махать флагом – “to wave a flag”
махать рукой – “to wave (with) a hand”

So рукой (instrumental singular of рука) is required by this idiomatic pattern.
Using руку (accusative) would be wrong here.

What does как будто add here? Is it the same as будто or словно?

Как будто means “as if / as though.” It introduces something that seems to be true, from the observer’s point of view:

…и как будто ждёт… – “…and it’s as if she is waiting…”

It shows that the speaker is interpreting the monkey’s behaviour; they don’t literally know what the monkey is thinking.

You can often replace:

как будто
будто
словно

with very similar meaning:

и будто ждёт…
и словно ждёт…

Как будто feels slightly more colloquial/conversational than plain будто, but in this sentence all three would sound natural.

Why is there a comma before когда in ждёт, когда ей помашут рукой?

In Russian, когда can introduce a subordinate clause of time. That clause is separated by a comma:

Main clause: (она) ждёт – “(she) is waiting”
Subordinate clause: когда ей помашут рукой – “when they will wave to her”

So we must separate them:

Она ждёт, когда ей помашут рукой.

This is similar to English “She is waiting for when they wave to her,” but in Russian the когда-clause is a normal subordinate clause and is always separated with a comma.

Both смотрит and ждёт are present tense. In English we would say “is looking” and “is waiting.” Is there any difference in Russian between “looks / is looking” and “waits / is waiting”?

Russian has one present tense form that covers both simple and continuous meanings:

смотрит can be:
- “looks” (general) or
- “is looking” (right now)
ждёт can be:
- “waits” or
- “is waiting”

Context tells you whether it’s a current ongoing action or a habitual one.
In your sentence, because we are describing a scene in progress, смотрит and ждёт clearly mean “is looking” and “is waiting.” There is no separate “continuous” form in Russian.

Is обезьяна always grammatically feminine, even if the monkey is male?

Yes. The noun обезьяна ends in -а and is grammatically feminine in Russian. So:

эта обезьяна, она, ей, её, ждёт (feminine agreement for adjectives/participles, etc.)

If you really need to specify biological sex, you can add words like:

самец обезьяны – “a male monkey”
самка обезьяны – “a female monkey”

But grammatically, обезьяна behaves as a feminine noun, and that’s why the pronoun later is ей (“to her”), not ему.