Fleshing out a Shapechanger Options

[Machiavelli]

Currently i am planning a new char which is basically a siberian-tiger shapeshifter. My GM recommended a realistic set of background informations and fitting handicaps. The rules haven´t been a problem up to now, but the more i think of the concept at all, the more i ask myself why the hell a siberian tiger would leave the wilderness and enter the "civilization". The new setting should take place in Berlin, but this doesn´t make the problem better. So please help me and give me a frame for this character. Why is he/she in germany. Why does he/she enter the shadows? Why should he/she stay there? Which gender should i take? Is there anything "cooler" than a siberian tiger or lion? (i tend to powergame, so i not only chose this species for coolness and style, but also for high attributes). Ist here e.g. some comparable critter that fits to middle europe (same stats preferrable). Is there any mentioning of extinct critters (like sabretooth-cat shapeshifters, cave-lion-shapeshifters, eg.)

I hope i could make the problem clear. I am highly thankful for any good backgorund story, appearance of the char-tipps, etc.

HELP^^