There is no average bear

In many ways, we can stereotype bears based on their age, sex, and reproductive status. While watching bears and even interacting with bears, certain stereotypes are useful. They help us begin to understand and explain a wide spectrum of behavior exhibited by a group of intelligent animals.

To stereotype a group of bears, adult males who rank at or near the top of the hierarchy are probably the least likely to act like a kid. They are the least likely to play or show overt curiosity towards new things. For most of bearcam’s history (2012-present) we’ve watched bears like 856, 747, and 814 dominate the falls through their size and assertiveness. These bears showed little interest in other bears except when establishing or reaffirming their dominance, stealing fish (especially 814 Lurch), appropriating preferred fishing spots, or when seeking a mate. Their behavior framed (biased?) our expectations of bears at the top of the hierarchy. They acted like stereotypical dominant males, and in their own ways, average bears.

But this logic can only take us so far, because there are no average bears.

This past July 32 Chunk displaced 856 as the most dominant bear at Brooks River. Chunk is approximately 12-13 years old and is perhaps the largest bear to use the river regularly this summer. Much of his behavior, especially early in Brooks River’s salmon run, is typical of a big dominant male. Not only did he displace other bears, he also wasn’t successfully challenged for food or fishing spots.

Notice how 856 quickly vacates the jacuzzi and doesn’t even attempt to challenge 32 Chunk.

Initially, 32 Chunk fit our expectations of a dominant male, but over the past two weeks or more bearcam has captured Chunk play fighting with another large, and older adult male, 755 Scare D Bear, as well as scavenging fish from him.

Just what is going on? Has Brooks Falls gone topsy-turvy in the wake of this summer’s hierarchy shift? Or this something more akin to the peculiarities of individual bear behavior during a summer when salmon are plentiful?

In July especially, Chunk fit the stereotype of a dominant adult male—challenging and displacing other bears, marking trees and cowboy walking in full view of other large males, and courting females. Since then, he’s behaved in ways that do not fit the dominant male stereotype—waiting patiently downstream of 755 for scraps of fish (a behavior more akin to scavenging than begging) and even initiating prolonged play fights with 755.

Play among adult male bears in their early teens is uncommon, but not unprecedented. I’ve previously wondered if bears outgrow play, and my personal observations suggest the frequency of play decreases as bears age. (I’m more surprised by 755 Scare D Bear’s willingness to play-fight, something I’ve never witnessed from him, than from 32’s).

Chunk’s play behavior separates him from bear 856 who was the most dominant bear seen through the entire history of bearcam until this summer. 856, like 24 BB before him, was hyper-dominant. As far as I know, this term has never been formally described in the scientific literature about bears. Tamara Olson, one of Katmai’s former bear biologists, introduced me to it. As I understand the term, hyper-dominance in bears is a willingness to continuously assert dominance over other competitors, giving them no slack, no chances to gain an edge. 856 became the river’s most dominant animal in 2011, when he was about the same age as Chunk is now. Once 856 became more dominant than 814 Lurch, for example, he repeatedly approached and displaced Lurch, perhaps in an effort to remind his large competitor, “Don’t challenge me or infringe on my space.”

Perhaps a lack of other large males who can challenge Chunk has allowed him to exhibit more playful and less hyper-dominant behavior. The relatively high abundance of salmon at Brooks River this summer also influences how bears interact with each other. To add another stereotype to the mix, bears are generally more playful and more tolerant of each other when they are well fed.

Because of his rank at the top of the hierarchy, we expect Chunk to behave like more like 856 than a youthful subadult. However, no biological edict commands Chunk to fit our expectations. His bimodal behavior is uncommon among adult male bears of his rank. Yet, Chunk can play-fight with other bears and still maintain an exceptionally high rank in the hierarchy.

The average bear is an amalgam of our observations and conclusions, created to help us better understand the lives of bears. No single bear will ever fit this role completely. Chunk can be both playful and dominant. He is no anomaly, because the average bear doesn’t exist.

Viral Bear Encounter with 435 Holly

Every once and a while a video from Brooks Camp goes viral. The latest involves a mother bear, her two spring cubs, and a person on the trail to the Brooks Camp Campground.

I’m a little late to opine on this video, but most of the responses and explanations (even Katmai’s, which explains what to do fairly well) seem to lack information about the bear’s behavior. Why did the mother bear and her cub approach the person?

The mother bear in the video is known as 435 Holly, an adult female who was first identified in 2001. This bear has led a storied life so far, successfully caring for her injured yearling in 2007 and adopting an abandoned yearling in 2014.

brown bear standing in grass near water

435 Holly in September 2015.

She’s also one of the most human habituated bears known at Brooks River. (Habituation, in this context, is a waning response to a neutral stimulus.) As a result, this bear is not as likely to react as defensively towards people compared to many other bears. Holly frequently uses the developed area from the river mouth to the campground, often traversing the area near Brooks Lodge, the NPS visitor center, and employee housing. She’s even treed herself near the bathrooms at Brooks Lodge and approached large groups of people.

The ranger handled this particular situation well, gathering the group of people together to let the bears pass. Corralling people isn’t easy though. Despite the best efforts of rangers, some people are always willing to push the limit with bears.

Bear near group of people. Arrow pointing towards person who is separate from group.

It’s not a wise move to leave the safety of your group when a mother and cubs is only feet away.

On more than one occasion, I watched Holly walk down “Park Avenue” in front of my cabin, sometimes to avoid other bears and sometimes just because that was the easiest way to get where she was going.

Her behavior demonstrates a relative tolerance for people. She’s not shy about using the same trails as us, which brings me back to the viral video. 435 Holly has encountered many, many people at Brooks River and humans have largely been a neutral stimulus in her life. These factors enable situations like these to happen on a regular basis at Brooks River.

In the viral video, neither Holly nor her cubs show signs of stress or defensiveness. She doesn’t lower her head, her ears remain upright, and she makes no vocalizations. Holly’s cubs reflect their mother’s relaxed state, casually walking with and occasionally in front of mom. They know a human is near and as he backs away, she continues in the same direction. Holly, in this situation, wanted to use the trail. She did not threaten the person or act in a defensive manner.

Of course, there was real risk involved during the encounter and my thoughts should not be misconstrued to downplay the risk. Any encounter with a bear, especially a mother and cubs, needs to be taken seriously, for our own safety and also for the welfare of the animals. If this was different mother bear, with different tolerances and reaction distances around people, then the situation could be different.

This doesn’t mean the person on the trail would be mauled, however. At Brooks River, females with cubs who are not habituated to people are likely to be displaced from the river during periods of high human use, and we shouldn’t approach bears just because they’ve shown tolerance towards us in the past. In areas where bears need more individual space it is even more important to prevent close encounters.

This encounter with 435 Holly and her cubs was the result of a very human habituated bear needing to use the trail at the same time as a person. Her motivation, in this particular case, wasn’t a need to protect her cubs, assert dominance over a person, or even curious approach. It was simply to walk on the trail.

For information about what to do in encounters like this at Brooks Camp, please see Katmai National Park’s video response. That response however, is not usually applicable to bear encounters in other areas of North America.

An Old Bear’s Teeth

480 Otis is currently the oldest adult male bear known to use Brooks River. First identified in 2001, a conservative age estimate places him in his early twenties. This bear is a skilled and patient angler who often sits for hours in Brooks River. When he catches salmon though, a common ailment of bears his age is noticeable.

bear in water biting salmon with side of his mouth

480 Otis often bites the tails off of salmon by utilizing his molars, a method that younger bears with all their canine teeth do not use.

In 2013, I first took note of the peculiar manner in which Otis eats his salmon. Unlike young bears with relatively sharp canine teeth and incisors, Otis sometimes seems to struggle with grasping and biting through the tough skin of sockeye salmon. He seemed to use his molars much more than younger bears to bite into salmon. After watching closely through binoculars, I eventually saw why. Otis is missing canine teeth.

Notice how he seems to have difficultly chewing his food.

Otis’ lower left canine appears to be completely missing. A nub of his upper right canine may still exist, but it is so small to be nearly useless. He may also have missing or worn incisors, premolars, and molars. This affects his ability to grasp and bite into salmon.

Even when salmon are so abundant that most bears high-grade their fish—eating the fattiest parts like the skin, brain, and eggs and discarding the rest of the carcass—Otis eats higher proportions of the whole fish, probably because his worn and missing teeth prevent him from handling the fish as dexterously as his younger competitors.

Throughout their lives, brown bears suffer from broken bones, disease, wounds, and many other ailments. As they age, the rigors of their diet and lifestyle wear on their teeth. Without access to a dentist, bears must tolerate broken and worn teeth as well as deep cavities and even abscessed teeth, conditions which may ultimately reduce their fitness and survival.

480 Otis is one of the most experienced bears at Brooks River. Despite his less than healthy teeth, he continues to fish quite successfully (incredibly, he once caught and ate 44 fish in about six hours!) to gain the calories needed to survive the lean months of winter and spring.

fat bear sitting in water in front of rock wall

 

A Close Encounter at Brooks River

 

Early today, bearcam captured a very close encounter of the ursine kind.

When the video begins, two people are walking out of the water in the direction of Brooks Lodge. A relatively small brown bear, probably a subadult, then begins to run towards them. Eventually, the bear gets very close to both individuals. Other than wading into very deep water, the couple had few options in this situation. Their only line of retreat was towards Brooks Lodge (the direction they were walking).

Screen shot of bear and person near each other. Text reads "Person and bear." The person and bear are in the yellow circle.

The bear could’ve approached the people for a few reasons. If the people were fishing and if they had a fish on their line, then this could have attracted the bear. If the bear had taken fish from anglers before, which happens at Brooks River, then it would be more likely to approach people as it searches for an easy meal. The splashing of their feet could’ve caught the bear’s attention. That’s a sound that mimics the sound of splashing fish, and for bears at Brooks River this is the sound of food. The bear could also have been attempting to play or assert its dominance.

The bear doesn’t look like it was charging the people defensively. Its bounds aren’t direct. In contrast to this bear, a charging bear moves very quickly in a straight line. Defensive bears, from what I’ve observed, do not deviate from their target until they decide to stop the charge.

There was one thing the couple could have done to reduce the chances of a scary encounter—stay together. Instead of walking 5-10 meters apart, they could’ve walked shoulder to shoulder. Size means a lot to a bear and bears are much less likely to approach groups of people compared to single people. Beyond anything else traveling in groups, especially groups of four or more people, is the most important step we can take to increase our level of safety in bear country. Most importantly, the couple could have not gone into that area.

People are permitted to be in that location, and often don’t consult rangers before doing so. However, I don’t necessarily place blame on them. Quite often, visitors are not aware how vulnerable they are in many places at Brooks River.

This is a place where people have a lot of freedom, maybe more so than any other well known bear viewing location in Alaska. The only area closed to people is the immediate area near Brooks Falls from June 15 to August 15. Situations like this don’t happen every day, but bears and people are often in very close proximity. I know many of us who watch the bearcam won’t visit Brooks Camp, but a few of us will. If you choose to visit, please consider ways in which you can minimize this type of encounter. I recommend staying on established trails and bear viewing from specific locations where bears expect to find people, like the wildlife viewing platforms. The river mouth often looks like a great place to be with its open sight lines. Yet, the depth of the water greatly limits where one can go to avoid bears. The river mouth from late June through July and again from late August through early October is wonderful habitat for bears. For this reason, everyone who visits Brooks Camp should consider not going into this area. This provides a higher level of safety for us and greater opportunities for bears to access the resources they need to survive without our interference.

Despite my best intentions over the years, I still got much too close to bears when I wasn’t paying attention to my surroundings, when I traveled into a spot where sight lines were limited, or when I was in an area where bears were likely to feed or rest. Close encounters will happen, but there are ways we can minimize the risk.

  • Watch bears from trails and the wildlife viewing platforms.
  • Avoid moving into areas where bears are likely to rest, play, or feed.
  • Give yourself two avenues of escape to avoid an approaching bear.

Related Posts:
Giving Bears Space
The Challenges of Managing Bears and People at Brooks Camp

Brooks River Water Temperature

Alaska is often described as a cold place, and justifiably so. Winters are long. Summer temperatures, especially on the Alaska Peninsula, are often damp and cool. It’s easy to imagine Brooks River’s water as bone-chillingly cold. But, just how cold is the water in Brooks River, the scene of bearcam? Brooks River is never very warm, but its temperature varies more than you might think. These temperature shifts can impact spawning salmon, but salmon are adapted to avoid the risk.

Staff from the National Park Service’s Southwest Alaska Network are tasked with monitoring the long term water quality in Katmai. During the summer, they install a data logger at the outlet of Lake Brooks where it drains into Brooks River to record water temperature. When the water temperature data is compiled into a graph, it displays quite a bit of variability.

Graph of water temperatures at the head of Brooks River. Verticle axis is degees in fahrenheit. Horizontal axis is time.

This graph plots water temperatures for the head of Brooks River from mid June to late August 2015. The blue line is a daily average of hourly temperature readings. The horizontal red, yellow, and orange lines represent State of Alaska water temperature threshold standards for fish habitat. Data courtesy of the National Park Service Southwest Alaska Network.

During the height of summer, Brooks River’s temperatures can rise well into the 60˚s F (15-20˚ C). Temperatures also drop rapidly, sometimes as much as ten to fifteen degrees in a few days. The maximum temperature recorded in 2015 was 69 °F (21˚ C) on August 2 at 5 p.m. and the minimum temperature was 44 °F (6.7˚ C) on July 5 at 8 a.m. What explains this variability?

Weather and the underwater topography of Lake Brooks drive the rise and fall of the river’s temperature in summer. Brooks River drains Lake Brooks, a large glacially carved basin. Lake Brooks is filled with crystal clear water, and most of the lake is very cold so we could expect Brooks River to remain cold too if it weren’t for a shallow shelf of sediment extending a few hundred yards offshore from the lake’s northeastern shoreline. Over the shelf, the water is only a few feet deep at most.

Screen shot from Google Earth. Text on page reads "Lake Brooks" and "Beginning of Brooks River." Eye altitude is 4623 feet.

Near the head of Brooks River, a shelf of sediment extends far out into Lake Brooks. In this Google Earth image, the shelf is outlined in blue.

view of lake and mountain

Brooks River begins at the northeast corner of Lake Brooks. The beginning of the river can be seen at center right.

When summer’s long days (Katmai experiences almost 19 hours of daylight at the summer solstice) combine with stretches of clear and sunny weather, the water above this shelf is warmed considerably. When cool, cloudy weather covers the region, the water over the shelf drops in temperature. Wind across Lake Brooks can also help stir the lake, perhaps even breaking the thermocline between warm water on the surface and the cold water underneath. Even a rough comparison of weather and the river’s water temperature shows a clear correlation.

Water temperature graph (top) and weather data graph (bottom).

On the weather graph (bottom), the red line represents the daily maximum temperature, the blue line represents the daily minimum temperature, and the green line represents the dew point. Peaks in the river’s water temperatures roughly correspond with long stretches of warm weather. Weather data graph courtesy of wunderground.com.

While warmer water temperatures may not affect bears, salmon are sensitive to it. If water temperatures exceed certain limits, then dissolved oxygen levels in the water can drop, increasing mortality rates for adults salmon, fry, and eggs, or altering the timing of migration and spawning. Importantly, water temperature drives incubation time for salmon eggs. Incubation rates for salmon eggs are slower in cold water and faster in warmer water. If the sockeye salmon in Brook River spawned in July, for example, then warmer water would decrease the incubation period for the newly spawned eggs, potentially causing them to hatch too early when no food is available for the fry. These temperatures would also increase egg mortality. Sockeye and coho salmon egg survival plummets when water temperatures reach 14˚C (57˚ F). (See pages 9-15 in ADF&G’s Technical Report 91-1).

Vertical axis represents survival % from 0-100. Horizontal axis represents temperture in degrees Celcius from 0-15. Caption on figure reads "Figure 8. Survival of coho and sockeye salmon eggs from Fertilizations to hatching at different temperatures. Data from Murray and McPhail (1988).

This graph displays sockeye and coho egg mortality compared to water temperature. Graph courtesy of the Alaska Department of Fish of Game.

The sockeye salmon that spawn in Brooks River avoid this risk by delaying their spawning until late August and September. Notice how water temperature on the graph plateaus then begins to decrease by the end of August.

Graph of water temperatures for Brooks River in August 2015. Verticle axis is degees in fahrenheit. Horizontal axis is time.

By late summer, day length has shortened by many hours. With less sunlight available to warm the water near the outlet of Lake Brooks, temperatures eventually dip well within ideal thresholds for spawning and egg incubation. The river’s salmon take advantage of these conditions by delaying their spawning until late summer and fall when cooler water temperatures, which continue to drop as fall wanes into winter, slow the salmon eggs’ incubation time. They don’t hatch until very late winter, and the fry don’t emerge from the stream gravel until spring when water temperatures begin to rise again and more sunlight supports more plankton, which feed the young salmon.

Brooks River is a dynamic place. No one week, no one year is the same as the last. Salmon, at least genetically, understand this. They “know” spawning in July would be risky business and probably unsuccessful. Their spawning cycle is timed to avoid the warmest and most variable water temperatures. In this way, every year, Brooks River’s salmon demonstrate their adaptation to variable conditions.

school of salmon in water with lake and mountains in background

End of an Era

The bear hierarchy is fluid. Bears jostle constantly within it, gaining and losing rank as they grow into adults and age into older bears. In 2017 at Brooks River, one bear has asserted his dominance over all others in ways he’s never done before. There appears to be a new dominant male on the river and he’s known as 32 Chunk.

bear standing in grass

32 Chunk in early June 2017. Photo courtesy of Katmai National Park.

In 2011, I began recording interactions between bears at Brooks Falls, noting who displaced who, who avoided who, and which bears were courting, stealing fish, and playing together. Out of hundreds of interactions I witnessed, one bear was consistently and clearly dominant over all others, 856.

bear standing in water

856 stands in Brooks River on June 30, 2016.

From 2011 to 2016, 856 wasn’t displaced once. I only noted him yielding on very rare occasions, like when he faced a particularly defensive mother bear. No other bears even seemed to challenge him. 856 ascended to the top of the hierarchy rather quickly in 2011, outcompeting other large males like 814 Lurch and 747, and for many years remained the river’s most dominant bear.

two bears facing each other in water

856 (right) displaces 747, another large adult male bear, from the jacuzzi in 2013.

Life at the top of the hierarchy is difficult, however. Other bears are subordinate, but not subservient, to more dominant animals. If injury, illness, or age weakens a dominant bear then others will not hesitate to usurp their position, gaining greater access to food and potential mates. Other bears, often younger and stronger, are more than willing to take your spot if given the opportunity.

In the video above, 856 is the bear in the jacuzzi (the plunge pool below Brooks Falls) while 402, an adult female, stands on the lip. Notice how 856 turns to face the bear approaching from the far side of the river. This is 32 Chunk.

Screen shot from video. Three bears near a waterfall. Text reads "402," "856," and "32 Chunk."

856 backs out of the jacuzzi to avoid 32 Chunk. He then goes to the lip where 402 stands, but 32 Chunk follows. Above the falls, 856 makes no attempt to challenge Chunk. 856 stands and watches as 32 turns away from his competitor, like dominant bears are apt to do, and walks out of the frame.

Generally, when two bears of approximately the same size and disposition meet for the first time, both bears posture openly as they evaluate each other’s size and the potential to do physical harm. 856 yielded quickly and readily to 32, so they have encountered each other before the video above was recorded. During a previous encounter 32 Chunk may have asserting his dominance even more clearly, hence 856’s willingness to yield. 856 simply saw 32 approach and instantaneously realized he could not challenge the larger 32, so he backed away to avoid picking a fight he probably wouldn’t win. (Many, if not most, interactions between bears are like this. They are defined by avoidance.)

bear standing in water and facing the right side of the photo

32 Chunk in 2014, while he ranked in the middle of the bear hierarchy for adult males.

Nature abhors a vacuum. No niche is left unfilled within the bear hierarchy. 856, perhaps weakened by injury or age, appears to no longer be the most dominant bear at Brooks River. His younger competitor sensed weakness and exploited it. This isn’t a contest of longevity though. During his time as the most dominant bear, 856 had free reign over the best fishing spots and went unchallenged for access to females in estrus. For years, he grew large and strong, probably siring more than one litter of bear cubs along the way. Now 32 Chunk (and possibly other bears like 747) hold those advantages.

856 remains a large bear and his size will continue to allow him great access to fishing spots at Brooks River. Bears grow up quickly, gaining the strength and skills necessary to survive a harsh, competitive world. Eventually though, the competition catches up.

Chunk Didn’t Displace 856

A few days ago, bearcam viewers alerted me to an interesting interaction at Brooks Falls where 32 Chunk appeared to displace 856.

I’ve taken some time to review bearcam footage of the subordinate bear in the video above, and I don’t think he is 856. The bear looks like an adult male, based on his size and the presence of scars around his face. I don’t recognize him, but I am willing to say it is not 856. Here’s why…

856 is a large adult male with blond ears and a long neck. This year he returned with a noticeable limp and sports a shed patch on his rump.

856 will fish at several different places in the falls—the jacuzzi, in the far pool, and near the rocks in between. When he sits at the rocks, he does so in a fairly distinctive manner.

When 856 fishes the jacuzzi, he’ll often leave that spot to eat near the island, almost sitting and facing away from the cam.

In contrast to these behaviors, the bear displaced by 32 Chunk doesn’t appear to be limping (and I’ll admit that bears can heal quickly, so the limp may not be very pronounced now). Both 856 and the unidentified bear may have similar wounds or scars on their face, the ears of the bear displaced by 32 Chunk are darker. The contrast between the unidentified male bear’s front quarters and hind quarters is also more apparent than 856. His muzzle appears blockier than 856, and 856 is very unlikely to play with 89 Backpack.

bear standing in water near waterfall

This is a screen shot of the unidentified adult male who displaced by 32 Chunk.

bear standing on grass near water

856 walking on the island near Brooks Falls in July 2015.

So was this a changing of the guard at Brooks Falls? Probably not. In my opinion, 32 Chunk displaced a full grown adult male, but the subordinate bear was not 856. However, in the absence of other large males like 856 and 747, 32 Chunk may be the most dominant bear on the river. Chunk clearly asserted his dominance over the unidentified male.

Almost every year, a new and fully mature adult bear shows up at Brooks River. Bears are creatures of habit, but they also remain flexible, changing their behaviors when necessary. The unidentified male may have never visited Brooks Falls before and never encountered 32 Chunk. His life up until now is a mystery, but these events are one reason why the story of Brooks River’s bears is so fascinating. This is a constantly evolving story. It will never become static.

View more photos of 856 from 2015 and 2016.
(Thanks to bearcam fan stmango for compiling many videos for me to review.)

Hierarchy Shift

Brown bears live in a hierarchy, where dominance allows greater access to food and the most productive fishing areas. One recent interaction between bears 32 Chunk and 480 Otis represents a shift in this social order. This is a story of maturation for two bears going in opposite hierarchical directions.

The hierarchy at Brooks River allows bears to quickly assess their competitors, avoiding most physical fights and saving valuable energy. Within the hierarchy large, mature males rank highest followed by other adult males, females with cubs, single females, and finally subadult bears. While this pattern holds as a general rule, bears shift their position in the hierarchy depending on their size, strength, and overall health.

As an adult male in his early teens, 32 Chunk is well positioned to rank near the top of the hierarchy. Chunk was first identified in 2007 as a chunky subadult bear. We don’t know his exact age, but bear monitoring staff noted he appeared to be a young subadult, perhaps 3.5 or 4.5 years old at the time. Since then, he’s grown considerably and is among the largest bears at Brooks River.

small bear standing in grass

32 Chunk as a young subadult in 2007. Ten years later, he has grown to become one of the largest bears at Brooks River. (Photo courtesy of Jeanne Roy.)

In contrast, 480 Otis was a mature adult in his early teens in 2007. He was a big, walrus-shaped bear who, like today, was skilled at fishing in the jacuzzi and far pool. He was not often displaced from his preferred fishing spots.

bear in water

480 Otis in 2007. (NPS Photo)

In 2007 and 2008, a young subadult bear like Chunk wouldn’t even consider challenging a larger adult like Otis. Since then both bears have matured, but their life histories since then lead in different directions within the hierarchy. Recently, 32 Chunk demonstrated his dominance over the older 480 Otis.

When the video begins, 480 Otis is standing upstream of the falls in the middle of the river. 32 Chunk is the darker colored bear in the jacuzzi below the falls.

screen shot from video of waterfall. one bear sits below the falls and another is in the river above the falls

After Chunk notices Otis above the falls, he leaves the jacuzzi and begins to approach Otis.

screen shot from video of waterfall

480 Otis starts to move away, possibly to avoid 32 Chunk’s approach. This is one sign Otis could be subordinate to 32. The rest of the interaction leaves no doubt who is dominant, however.

screen shot from video. Dark bear approaching another bear above the waterfall.

Chunk moves through the river faster than Otis. When Chunk nears the older bear, Otis turns to face the younger competitor. They stand mostly still, yawning and assessing each other’s size.

screen shot from video. two bears standing in river above the falls.

32 Chunk then swats at 480 Otis.

screen shot from video. bear swats at another, splashing water

In the video, the bears’ ear positions aren’t easy to see, but 480’s ears seem to be held back against his head, indicating he’s somewhat defensive. Chunk’s ears, in contrast, are mostly upright and oriented forward, a sign of assertiveness and dominance in this context.

screen shot from video. two bears standing near each other in water

The interaction ends when 32 Chunk walks away with 480 Otis watching.

screen shot from video. Dark bear walking away from lighter bear

Several behavioral cues demonstrate 32 Chunk’s dominance and 480 Otis’ subordinate status in this interaction.

  • 32 directly approached 480.
  • 480 attempted to avoid 32.
  • 32 lunged at 480 and 480 did not attempt to engage.
  • 32’s ears were upright and forward, while 480’s ears were held slightly back against his head.
  • 32 ended the encounter, turning his back on 480 and walking away. (Dominant bears decide when an interaction ends unless they have good reason to usurp a resource such as food, a fishing spot, or access to a potential mate.)

Chunk is now entering the prime of his life where he’ll attain his greatest size and rank, and while Otis remains a large bear he’s no longer able to compete with the largest male bears for fishing spots. It seems that Chunk recognizes his size and strength and Otis recognizes the great risks of challenging a younger, larger bear. For the rest of the summer, 32 may displace 480 from fishing spots at Brooks Falls.

Chunk appears to be moving up the hierarchy while Otis continues to slide down it. With these bears, there are two tales of maturation.

When Mother Bears Collide (Again)

Last summer, 128 Grazer and 409 Beadnose found themselves face to face in defense of their cubs . Recently on bearcam, they had another dustup. This one was unique and included elements I had never observed before.

When we ask, “Why did that bear behave like that?” we should ask two additional questions.

  • Was the bear motivated by food or potential access to food?
  • Was the bear motivated by sex or reproductive success?

Biology can be distilled simplistically into two categories: food and sex. Adequate nutrition is necessary for survival of the individual, and since bears hibernate throughout much of the year they are particularly motivated by food. Reproduction also drives bears to behave in particular ways. We should also consider how each bear’s disposition influences their behavior.

128 Grazer
As a young adult bear, 128 Grazer became very skilled at fishing the lip of the falls. She’d compete for access to that spot with several other adult males and females. As a single bear (i.e. no cubs), she was fairly tolerant of other bears in close proximity. After 128 became a mother in 2016 though, her behavior became increasingly defensive. She didn’t shy away from confronting larger adult males in order to protect her cubs .

Still caring for three yearlings in 2017, she seems to be just as protective and wary as last year.

409 Beadnose
In contrast to Grazer, 409 Beadnose is an experienced mother who has weaned three litters (her current batch of yearlings is her fourth known litter). Beadnose can be defensive too, but tends to avoid confrontation more often than 128. While Grazer visited the falls with her spring cubs last summer, 409 did not. This is a clear behavioral change for Beadnose, because she visits the falls frequently when she’s not caring for cubs.

two bears standing in shallow water

128 Grazer (left) and 409 Beadnose are familiar with each other and often use the same areas to fish.

Now both of these mothers are raising yearlings, both have returned to Brooks Falls, and both tend to fish the same places (the lip or the far pool). Most importantly, both are competing for the same resources in order to successfully raise their cubs—leading to situations like this.

Can this apparent snafu be explained by a motivation for food or reproductive success? When the video begins, 409 Beadnose is ascending the hill. 128 Grazer is the blonder bear standing under the spruce tree. Grazer refuses to yield to Beadnose’s approach. The bears jaw and growl at each other, while 128’s yearlings remain in the spruce tree above their mom.

screen shot of bears beneath spruce tree

Beadnose seems compelled to get up the hill and skirts Grazer. There are other routes available, but she sticks with this one.

screen shot of brown bear on hill near spruce tree

Grazer’s cubs eventually come down from the tree while Beadnose lingers in the forest nearby. Something keeps Beadnose from moving farther away, but at this point we can’t see her.

bears standing on his near river

With 409 still on the hill, Grazer and cubs move down to the river. Shortly afterward her yearlings react to something in the same tree they had just climbed down from. Grazer begins to jaw pop, a loud and distinctive warning noise. We can see movement in the spruce tree above.

four bears standing in river near a steep embankment

It’s one of Beadnose’s cubs.

four bears standing in river. Yellow circle surrounds bear in tree. Text reads, "409 yearling"

Grazer and her yearlings scramble up the hill just 409’s yearling tries to climb down. Now we understand why Beadnose didn’t give Grazer more space previously and why Beadnose remained in the forest near spruce tree—one of her cubs was in the same tree as Grazer’s cubs! This is something I never witnessed before, cubs from two litters in the same tree at the same time.

409 is mostly out of sight as 128 and cubs run up the hill. 409’s yearling though, is unable to get out of the tree.

Two bears climbing a hill. Yellow circle highlights a bear in a spruce tree. Text reads, "409 Yearling"

A short stand-off ensues. 409’s yearling remains in the tree, 409 stands not far up the hill, and 128 Grazer and yearlings remain close by.

Screen shot of bears on hill in vegetation. Yellow circles highlight location of bears. Text reads, from top to bottom, "409 yearling" "409 Beadnose" "128 Grazer"

When 409’s cub tries to climb down again, Grazer reacts and charges to the base of the tree.

screen shot of bear standing on hill near river

Grazer then climbs the tree, forcing Beadnose’s yearling back up. About ninety seconds later, 128 has moved farther away, which allows 409’s cub to climb out of the tree and rejoin its mother.

This interaction between Grazer and Beadnose was unique because cubs from two different litters were in the same tree at the same time, greatly complicating a situation where the families could’ve avoided each other. The interaction was ordinary however, because both Beadnose’s and Grazer’s behavior seemed to be motivated by an urge to protect their cubs. Grazer’s defensiveness is easily triggered and she must’ve viewed the 409 yearling as a threat, which in my opinion led her to chase it back up the tree. Beadnose may have realized Grazer was willing to physically fight in this situation. This could’ve deterred Beadnose from standing next to the tree under her cub. At the beginning of the video, Beadnose also couldn’t get her cub out of the tree with Grazer’s cubs still in it. Stuck in a Catch-22, Beadnose seemed to choose a more cautious tactic: move slightly away and wait.

Motivation for food or reproductive success explains quite a lot in biology, but not all bear behavior can be explained so simplistically (why would a bear play with her foot? ). The prolonged interaction between these families however, does fit one of the biological motivators. This interaction probably wasn’t hierarchical; that is, it wasn’t about asserting dominance for access to food and mates. It was about protecting offspring. In other words, it was about reproduction.