This legend seems to be scattered throughout the document and I couldn't find a coherent story under this title. However, there are several references to a bear in different contexts.
For example, there's a story about a woman who was abducted by a bear and gave birth to a hairy child. There's also a story about a boy named Icmá (Plenty-of-Hair) who was strong and once quarreled with other boys and killed them with a single blow. He later went on a journey and met an ogre that he fought and killed. These stories might be part of the legend you're looking for, but without more specific information, it's difficult to piece together the entire legend.