Each team will begin the race with as many as 16 dogs in harness, but must finish with at least 5. 

Those dogs unable to finish are dropped at checkpoints along the trail and are flown back to the Anchorage State Penitentiary.  The inmates have competed all year for the privilege of caring for one of the 'drop dogs' until its owner finishes the race.

The dogs will burn 8000 calories per day during the race.  They have to be fed on Salmon, chicken and fish.  They have vitamin supplements put into their diet and for the female dogs heat suppressants.