Yes, it is strange for a native English speaker like me to think that 'The lion is in the zoo' is the same as 'The lion stays in the zoo'. Correct me if I'm wrong, but I think this is an explanation.
In English the verb "to be" (in this case 'is') is used for identification , description and location. i.e. Who/What is it? It is a lion. What is it like? it is yellow, it is dangerous, etc. And where is it? It is in the zoo.
In Italian, it is possible/common to use another verb, 'stare', for location, rather than 'essere'.
Being a native English speaker, this seems weird to me as well, but being fluent in Spanish, I already understand these sorts of differences. I don't think it would be quite as constructive to just say " sta- stay " because the difference between essere and stare mirrors estar and ser in Spanish, and that's not nearly as easy.
On another note, if you were to say "stays" or "remains", is there a better translation for that word? In Spanish you would use quedar instead of estar, and that would be the difference between "stays" and "is located in". Is there an Italian equivalent?
No, current location is always expressed as temporary. If you want to get really picky, most of the permanent things can be changed, and many of the changeable stay the same way for a while (for example, you could argue that someone shouldn't say "sono una donna" because people can have sex change operations, making the state of being a woman or a man potentially a temporary one; or you could move to another country and change your nationality, making that no longer permanent; conversely, you could have agoraphobia and never leave the house, so your location would always be the same). The point is, this is a rule of thumb that can help a non-native speaker understand when native speakers choose to use one verb over another.
Here is some more information if you're curious: http://serenaitalian.wordpress.com/2010/09/09/difference-between-stare-and-essere/
sta is something temporary. "lei sta grassa!" means "she is fat" in a sense that its something temporary, maybe because she ate some 3 panini in the last weekend xDDD., so she could lose weight. but if you say lei È grossa, it means that she IS fat. she's always been. maybe it runs on her veins, or she really finds it hard to lose weight. it is also as something to refer to geopgraphical positioning. for instance, lui sta en nova iorque means he's in new york.
Spanish and Italian verb "to be" follows the same logic: (just a minor wordplay on the letters lol) IF you refer to something more permanent, like a physical or personality characteristic. SPANISH: ser, ITALIAN: essere IF you refer to something more temporary, like an emotion, location, or condition. SPANISH: estar, ITALIAN: stare and both have their own respective conjugations for I, YOU (formal), YOU (familiar), HE/SHE, WE, THEY that needs to be learned by heart.
I'm a Spanish speaker, and the differences between è and sta in Italian are the same ones as in Spanish. It's hard to understand for English speakers, I know it because I've been teaching Spanish to English and American people and I think this is the most difficult thing to understand for them... I couldn't give you an explanation of when we have to use each verb, it is something I know because I am a native speaker. My piece of advice for you is practise a lot and read books, since these verbs are mostly common in this language. Buona fortuna :)
But why is my translation "The lion is in the zoo" deemed wrong?
"The lion stays in the zoo" is typically the sort of slightly strange-sounding English that Italian native speakers sometimes use, though they entirely have my sympathy. I do understand that the reverse mistake by native English speakers like me, "Il leone è nello zoo" needs to be unlearned. The distinction between "to be somewhere" and "to sit somewhere", "to stand somewhere", "to stay somewhere" or even "to find itself somewhere" is much finer in most other languages than in English. (Such as French, Dutch, Spanish, Thai, and as here, Italian.)
No, it is right also. Stare = "To stay" (or to be) & essere = "to be". So the use of essere (e) is saying that the line is in the zoo, it does not stay there it is in there. The use of stare (Sta) says that it stays in the zoo, that is its home. I am not an expert, I am just beginning too. But that is the way that I understand it.