Pros:
Life steal as passive
Very high movement speed when E (Blood Scent ability activate

Cons:
Low mana at first
Most junglers try to kill Lizard Elder or Golem first and die then

Warwick is great jungler. He steal life as passive and his ability steals life too so warwick is great jungler. ad in this build he can kill baron alone and loses almost non health so what is better than solo baron and lose almost none health?

First buy Cloth Armor and 4 Health Potion when you recall again you should have something around 700 money, so buy Madred's Razors and go to jungle again and kill Lizard Elder. Now when you have ganked you should have money for Recurve Bow which means that you hit faster, which means that you hit 500 damage to minions more often and steal life of course. Now when you have ganked again recall when you have enough money for Madred's Bloodrazors and then go to dragon. Now follow build to the end of game!

First go kill 2 golems near bottom lane (when playing purple top lane) Then use a health potion and go to wraiths kill blue first. Now use another health potion and go to wolfs and kill them too and then use smite to kill neutral minions from enemies side (you can use smite everytime) and when you have something around 700 money recall and buy Madred's Razors and go to kill Lizard Elder. When you have buff start ganking! With Lizard Elder's buff you slow and burn them (they take damage even when you won't hit them). Then go jungle again and gank through game.

I need someone to help me making guides, if you are interested PM to me!