Final answer:
In 'Echo Mountain Grizzly,' the fate of the bear's other cub is not explicitly stated. It can be assumed that the cub either wandered off or was taken by another predator.
Step-by-step explanation:
In the book 'Echo Mountain Grizzly,' the fate of the bear's other cub is not explicitly stated. However, based on the information provided, it can be assumed that the other cub either wandered off on its own or was taken by another predator. This is supported by the fact that the main character observed multiple animals moving towards the brook, suggesting the presence of other animals in the area.