Koda's mother is a minor character in Brother Bear.
She is the first bear to be seen in the film. She fights against Kenai and his brothers in order to protect her son and ended up falling off a glacier when Sitka broke the part she was on in order to save his brothers. She survives the fall and runs off. She is later chased and killed by a vengeful Kenai, who blames her for killing his brother. She is then taken into the world of the Great Spirits.
She is mentioned various times in the film after these events, and is also seen in Kenai's flashbacks when he puts the pieces of Koda's story together.
When Kenai was hiding in the berry bushes Koda's mother appeared and Kenai thought that she is looking for him. But she was really calling for Koda.
She is last seen in in spirit form nuzzling her son and then, along with Sitka, returns to the Great Spirits.
She is not seen in the second film, but is mentioned. When Kenai is missing Nita, Koda asks her and the spirits to change Kenai back into a man so he can be happy.