Answer:
I am a busy worker who is a water mammal.
To cross the water I'm the way. For water I'm above I touch it not and truth to say I neither swim nor move.
I help you carry your books.
A necessity to some a treasure to many I'm best enjoyed among pleasant company. Some like me hot some like me cold. Some prefer mild some like me bold.
I get thrown in the air and will fall down. I get thrown down and I will rise in the air. What am I?
I break away from my pack. I create holes in my victims. I can travel for miles and then disappear. I am part of a dying breed. What am I?