I disagree with Franklin's suggestion. I do not think a country with an edible national symbol is really a good idea.
A tasty national symbol that can put diners to sleep when eaten is probably not the best choice.
The French and the Portuguese have a small infatuation for roosters, but the French have come to prefer Marianne, a human, as the favorite symbol of the country.
The rooster has a nice story to go with it in Portugal. from Wikipedia:
The Galo de Barcelos (Rooster of Barcelos) is one of the most common emblems of Portugal. These pieces of craftsmanship, made ??in painted clay in the city of Barcelos celebrate an old legend that tells the story of a dead rooster's miraculous intervention in proving the innocence of a man who had been falsely accused and sentenced to death.
The dragon was used as the crest of the Royal Arms of Portugal since the 15th century. Later, two dragons were also used as supports of the Arms of Portugal.
The Welsh and the Chinese also use the dragon. As a national symbol, the dragon has much to recommend it: it is inedible, since it is nonexistent, and it is large and not to be messed with. Of course, in come Christian mythologies, such as that of Poland, it is associated with Satan. That is a decided disadvantage.
Of course, there are too many legends about people SLAYING dragons. Slaying eagles, condors or even turkeys just for the Hell of it is rare.
The American bison is a good symbol until you get up close. Bisons have a pungent aroma and are bad-tempered. They easily outrun humans and would just as soon trample an American as any other human.
Dogs are certainly loyal, but you would have to choose a breed. Would a Golden Lab be a good symbol of the US?
Coyotes are clever and certainly American. But they like stealing chickens.
Mountain lions/pumas/cougars are another pretty good choice. The British, the Belgians, and many others like lions, but the fact is that the last wild lion in Europe died way back in Roman times. Lions smell awful, by the way.
EVery South American country that has condors uses them as the national bird. They have really ugly vulture heads, but they are huge and certainly embody (1) freedom as they soar above the Andes and (2) don't mess with me.
The Harpy eagle is quite impressive, but Venezuela has not chosen it, even though they have more than anyone else.
We have no harpy eagles in the US. A harpy eagle would easily have a bald eagle for lunch, if it were hungry. They are as big as an eagle gets.
New Guinea also has a species of harpy eagle.
Like all eagles, it will eat carrion and barf up breakfast to its eaglets.
It is hard to select a national symbol.
I have always been rather partial to the Kansas Jayhawk, and the Jackalope. Like the dragons, they are mythical and therefore more hygenic in their habits. You can't smell them, either.