Surprises of the Bear World

July 11, 2014 Posted by: Michael Fitz
Bear 856 follows bear 402 downstream of Brooks Falls
Bear 856 (lower left) follows bear 402 (upper right) downstream of Brooks Falls. (NPS/M. Fitz)

Katmai’s female bears go through a somewhat predictable cycle. They go to the den in the fall, hibernate in winter, and emerge in the spring. They mate in late spring and very early summer. They keep their cubs for 2-3 summers, den with them for one more winter and drive their cubs away in the spring. They nurse their offspring while caring for them and don’t go into estrus while nursing. These behaviors happen with regularity and are the “norm.” However, bear behavior is full of surprises.

The behavior of bear 402 is illustrating this now. As of yesterday (July 10, 2014) she still had one yearling cub. If 402 was following the “normal” pattern for bears, she would still be nursing that yearling and would not go into estrus. However, bear 856 (a very dominant male bear at Brooks River) seems to think otherwise. Over the past few days, he has been following her incessantly—just like he would if she were in estrus. I must note, that I have no evidence she is in estrus, only that the behavior of the two animals suggests she is.

Male bears can gauge a female bear’s receptivity to mating through scent. It appears that 402 may smell “right” to 856 even though she still has a cub. 856 has been following her non-stop for more than two days as 402 wanders the river and occasionally fishes. 402 has not been especially receptive to 856’s advances.

This isn’t good news for the yearling cub. 856 is not a bear that the yearling will want to get close to, even with its mother’s protective services. Last night, the cub was in a tree about 100 meters behind the viewing platform at Brooks Falls. The cub was seen in that tree on the night of the July 9, it was there on the morning of July 10, and was still there at 9 PM that evening. From what I have observed, 856 has not shown interest in the yearling cub, but this morning it was not there. Bears are very tolerant of physical discomfort, but eventually dehydration and hunger will force the cub to leave the tree.

Bear 402's yearling cub in a tree near Brooks Falls
Bear 402's yearling cub has sought refuge and safety in a spruce tree near Brooks Falls. (NPS/M. Fitz)

Meanwhile, 856 is still following 402 and the yearling cub’s whereabouts are unknown. According to the “norm” 856 should be ignoring 402. She shouldn’t be in estrus. It is easy to stereotype bears, but the ongoing story of 402, her yearling, and 856 demonstrates that bear behavior is quite variable and full of surprises. Not everything you see on the bearcams will fit the norm.

Update: July 14, 2014

402's abandoned yearling on the beach at Brooks Camp
402's abandoned yearling, now an independent subadult, walks alone along the beach at Brooks Camp. (NPS/M. Fitz)

856 was still following 402 on Sunday. Reports of 856 following a different female may have been erroneous.

I watched 402’s former yearling cub wander through Brooks Camp alone at 8 AM this morning. A ranger also reported seeing it alone on Saturday morning. 402 appears to have abandoned this cub. Why? I don’t know. Bears might abandon their cubs if the cubs are too weak to keep up or if the mother can’t devote the energy needed to support the cubs. I also don’t know if this cub is truly abandoned. Although very rare, mother bears have been separated from their cubs for over 2 weeks before reuniting. We haven’t observed 402 abandon a cub before, but this behavior is not unprecedented amongst brown bears.

It’s also important to note that 856 showed no interest in the yearling during the past week. His actions indicate that he is interested in mating with 402. He was never seen chasing the yearling or even investigating the yearling when it was treed near Brooks Falls. His consistent pursuit of 402 certainly didn’t help the yearling, but he may not have been the reason for its abandonment. 402 may have gone into estrus and abandoned the yearling anyway.

Is 402 a “bad” mother for abandoning her yearling? It would seem so from a human perspective, but we cannot define or label bears with our system of cultural norms, ethics, and morals. Bears and wild animals exist in a world outside of these things. 402 doesn’t have the ability to control her estrus cycle, no more so than a woman can. If she went back into estrus (which appears likely now), then 856 or any other adult male would be looking to mate with her. She would be unable to care for a cub while being closely pursued by a dominant adult male.

402’s former yearling cub should now be called a subadult bear since it is now appears to be on its own. It faces an uphill battle to survive this summer.

Update:

On July 21, after a courtship lasting about 12 days, 856 mated with 402 near the falls. This confirms that 402 was indeed in estrus and that may triggered 402’s abandonment of her yearling. The abandoned yearling, remarkably, found a new mother.

Last updated: April 14, 2015

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