Because I wanted the story to begin in London, I decided to base my main hero and his family on a traditionally British animal. The story begins with a small family of animals who come from outside of the London Zoo who have made their home among the zoo animals. Because of this, they would need to hide from the humans who work at the zoo, so they cannot be enormous like a deer or a horse (the exception to this being a fox as they are traditionally seen as being sneaky). They would need to be small and stealthy like a mouse or rat. However, mice and rats are very much overused within animated stories where the heroes are rodents. I decided to look at other small mammals native to the British Isles.
Again, because the setting begins in a zoo, this gives me limitless oppertunities to create some interesting characters since not all animals in London Zoo would be from around the British Isles. I looked, in particular, at animals from both Britain and South America, since they would be most related to the story narrative.
Matching animals with Personalities
Hedgehog: Nervous, Paranoid, Timid, Prone to curling up into a ball when scared.
Bat: Grizzled war veteran, used to be a 'pilot'. Always loves to segway to stories about his times in the royal airforce.
Pidgeon: Upper class, posh, looks down on others.
Sloth: Slow to speak, wise, absent-minded.
Golden McCaw: Talkative // (New Arrival Parrot which tells zoo about El Dorado: Grizzled, Eccentric)
Greater Yellow-Headed Vulture: Manpulative, greedy, sneaky, conniving.
Toucan: Flamboyant, eccentric, boisterous
Because the animal world would need an equivilent for El Dorado (the human El Dorado would be much too large of a scale) I would have to size down the legendary city to scale with the 'miniature' story that would take place within the human world. I came up with the idea of a secret, ancient vault of gold hidden in South America filled with treasures that would be adapted by the South African wildlife into a sprawling city; cups and chalices turned into miniature houses, coins as tables and wheels and carved into cogs, jewels as mirrors... etc.