I never thought about the question of whether, in languages that require nouns to have grammatical gender, particular countries may have a different grammatical gender from others, but on reflection I already know examples where they do in Portuguese: o Brasil, o Canadá (amusing to me because of the national anthem), but a Argentina, a Alemanha.
I wonder if this also happens in German; the only examples I'm thinking of offhand are feminine (die Schweiz, die Türkei) but now I'm not at all sure that there isn't a masculine one too!
Actually I can't think of many cases where German would use pronouns with countries. The reason these are masculine is because they are typically referred to using a definitive pronoun (literally "the Iraq", "the Iran", etc). It's more common with names of regions -- which may indicate that these countries used to be mere geographical regions (rather than sovereign nations) when the names entered the German language.
It also happens with countries like the UK, the US, the Czech Republic and so on, but obviously for the same reasons as in English.
I can't actually think of a country that's feminine in German. The "die" you often see is actually indicating plural (e.g. "die vereinigten Staaten", the United States; or "die Niederlande", "the Netherlands").
When you use pronouns for anaphora, would you use "es" for all countries, or is it plausible to imagine "er" or "sie", as with common nouns?
For example: Vor drei Monaten waren meine Mutter und ich in der Schweiz; wir haben _____ wirklich schön gefunden.
Would you accept "sie" here as a reference to Switzerland (because it was referred to as "die Schweiz"), or "es", or both? My intution is "es", but I'm not not a native speaker and non-native German speakers notoriously over-apply "es" to inanimate things.
I'd use "es" because it refers to the experience of being in Switzerland rather than the country itself.
But Switzerland is another example of a country that is typically used with an article. Consider the sentence "Ich fahre nach ____" with a country name. It doesn't work for countries like Switzerland ("nach Schweiz" sounds wrong, you'd instead say "in die Schweiz" -- same as "nach Kongo" vs "in den Kongo").
Several countries have articles in German, most don't. Plural countries (USA, UAE) have the plural article, which in the standard form is the same as the feminine article ("die") which makes for even more confusion, but when used in a case changes differently ("in den USA" vs "in der Schweiz") :)
Some feminine countries: Switzerland, the Dominican Republic, Mongolia, Slovakia, Turkey, Ukraine, Central African Republic.
Male, in addition to your own list: Niger (!= Nigeria), Sudan, Vatican.
Neutral: UK (because kingdom is a neutral noun in German), potentially others
In their native tongues, sure. But we're not talking about Afrikaans or French, we're talking about English. And since Britannia is feminine, English would have developed with the word "motherland" representing the native country.