Katak, le brave béluga description:

The coming of age story of a young beluga named Katak. While his peers have all turned white, something expected at their age, Katak is late in his body development. To prove that he has grown up and to grant the last wish of his adored grandma, Katak departs on a perilous journey to the Great North. Along the way he encounters deadly beasts and makes unlikely friends. You do not have to be big to be brave.