402 and her four cubs walk near the mouth of Brooks River. NPS/T. Hostetter.
402, a well known adult female, returned to Brooks River yesterday with a litter of not one, not two, not three, but FOUR spring cubs. Litter size for female brown bears in the Katmai region averages 2-3, so a litter of four cubs is large. It isn’t unprecedented, however. Over the past ten years, we know of four bears, including 402, at Brooks River have had litters of four spring cubs.
- 236 Milkshake in 2003
- 216 Marilyn in 2005
- 236 Milkshake in 2010
- 875 in 2010
- 402 in 2015
236 Milkshake attempted to raise a litter of four in 2003. Two of those cubs survived through their second summer and were presumably weaned in the spring of 2005. NPS photo.
In 2010, 236 Milkshake returned with another litter of four cubs. By the end of 2011, however, she had lost the entire litter. NPS photo.
Also in 2010, 875 fished at Brooks River with her litter of four. NPS photo.
Spring cubs can drink up to 45 ounces of milk per day. A female bear raising four cubs needs to produce 1.4 gallon’s of milk everyday! As cubs age and grow, they become less dependent on mother’s milk, but during the first few months away from the den, cubs eat very little but mother’s milk.
402, therefore, faces a huge energetic challenge. Will she be able to meet it? If salmon and other food sources are plentiful and she stay healthy, then she might. It won’t be easy though. Raising cubs is difficult and energetically taxing. Females sacrifice a lot for the welfare of their offspring, not the least of which is fat. This family’s continuing story allows us to watch and marvel once more at the survival instincts and adaptations of brown bears.
402 swims across Brooks River with her cubs on July 8, 2015. She is looking back toward her fourth cub which is still in the grass. R. Wood photo.