The shaman or witch doctor, has magical powers.  To assist him and to placate the gods 
he is able to transform into another form. Ths shaman would choose a form approriate to the need.

For agility he would choose a caribou; for strength the Polar Bear or Muskox; 
for travelling long distance the bird and to meet the sea gods he would transform into a seal, a whale or a walrus.

If more than one was needed you might see an unusual combination emerging.  The Inuit both fear and revere the shaman.  It is the shaman they turn to in times of need