The Tale of Urso Brunov Little Father of All Bears by Brian Jacques, illustrated by Alexi Natchev

From chapters.ca:
This tall tale from Redwall creator Brian Jacques features a brand new hero: Urso Brunov, the Little Father of All Bears. The strongest, wisest, bravest bear in the world, he is also the smallest, no bigger than the size of your thumb. Other animals of the forest stand in awe of him - except one: a mustached monster who captures four of Urso’s bears and puts them in his zoo, but who learns all too soon that the Little Father is truly a force to be reckoned with. On his way to rescue the lost bears, Urso Brunov matches wits with a tribe of boars, teaches manners to a billygoat, skims across the Deep River on a wooden flute, and finally confronts the Lord of All Sands. He’ll get those bears back, never fear - believe him, for he is Urso Brunov!