Here it is important to note the function of the words. "Qual" is the interrogative pronoun, functioning as the subject of the sentence. "Cane" is the predicate nominative. The "è" between them functions as the = sign.
In your translation "which" becomes the interrogative adjective, and "dog" becomes the subject of the sentence. "It", which doesn't appear anywhere in the Italian sentence, has appeared magically to become the predicate pronoun.
The question is fundamentally asking: which (out of the many options) is the dog? Your translation is fundamentally asking: which dog (out of a group of dogs) is it?
Great explanation for this usage. The sentence I saw with "Qual" before this one was with the possessive pronoun, e.g. "Qual e il tuo cane?" and there I think that either "Which dog is yours?" or "Which is your dog?" would be acceptable translations into English (if anything, I"d probably use the first more than the second, even though the second is grammatically closer to the Italian). By removing the possessive pronoun, it reveals both a grammatical and meaning/usage difference "Which x is...?" and "Which is...?"
Ex. 1You are learning Italian and you are at the park with an Italian exchange student who is learning English. He asks you this question.
Ex. 2 You are taking your baby for a stroll in the park and the child sees many different animals. You kneel down and ask the child this question.
Ex. 3 You are learning Italian on Duolingo's website and they ask you to translate this phrase.
Jae's explanation may be imaginative, but it was by using imagination that he found an answer for you. Next time before you relegate a phrase to the scrap heap, remember that many of the people here make (made) their living as writers. But most of all, don't be so quick to give up- you can do this.
Marking this comment down is silly. People need to know that its is the correct usage here as a possesive. It's ALWAYS means it is.
I kept getting this wrong because "cane" and "carne" sound almost the same to me. Then I went back to double check and realized that it's "la carne" and "il cane," so "il cane" is the only possible answer here. I'm not fluent yet in any language that has grammatical gender, so one more thing to learn to keep track of. LOL
I notice that there is no elision. This potentially changes the meaning. Qual'è = Quale è and means "which is it". In this case Qual è was used without the apostrophe, Qual è = "what is it" (when referring to a potential choice). Qual è la torta = What is the cake? Qual è il cane = What is the dog?