Questions & Answers about Я никогда не видел волка.
Why do we use both никогда and не?
In English, we say 'I have never seen', but Russian requires a double negative. When you use a negative word like никогда (never), you must also put не (not) before the verb. Literally, it translates to 'I never did not see'.
Why is the word for wolf волка instead of its dictionary form волк?
Because it is the direct object of the verb. For masculine animate nouns (living things like a wolf), the Accusative case takes the exact same form as the Genitive case, which adds an -a to make волка. Also, because the verb is negated (не видел), it can trigger the Genitive of negation, which also results in волка.
How would this sentence change if it said 'I have never seen wolves' (plural)?
You would change волка to волков. This matches what you are learning right now: for animate plural nouns, the Accusative plural looks exactly like the Genitive plural.