Udyr is a strong and fairly tanky melee jungler with one of the quickest jungles in the game.

Pro's
Udyr has brilliant jungle speeds and sustain. He can also gank once he has his bear stance allowing money to stack up quickly.
Con's
He is not an easy champion to learn. Although once you know how to play him he is incredibly good.

You should start at Wolves and using your R take them out quickly before moving onto Blue Buff. After then you should be level 2 that should allow you to take Wraith's quickly before pursuing onto Golem's and then back to Wolves and Wraith's before your first base.

Sorry this guide is short but if you follow it you should have a lot of success as Udyr - The Animal Spirit.