Category Archives: Bears

Geographic Insights about Big Bear Lake

Most visitors to Big Bear Lake come from the urban sprawl of Southern California, city dwellers at heart. Few have a real appreciation of the underlying geology or geography that circumscribes the place they visit for the rest and recreation found at Big Bear. They are exquisitely well positioned to appreciate the built environment, from the lakeside marinas to the range of lodging at Big Bear Lake. But the natural environment is not well understood.

There’s something really special about Big Bear and its environs. Nestled in the mountains, this 7 mile long alpine lake, which originally existed as a shallow lake and marsh (before the dam made it deeper), drains a watershed stretching from the high desert on the northwest (see California Tourist Guide for maps and info about Deserts and Inland Empire) to the Santa Ana river watershed to the east. It’s located at a high elevation (6,750 feet at lake level), which means that it stays cool/cold year round and thus explains the extended skiing season available for 6 months a year, even though it is near to balmy Los Angeles.

In fact, the elevation explains the heavy precipitation, too. Big Bear receives about 5 feet of snow a year, and some years can be almost double that. While that’s great for skiing, the principal value is feeding the fresh water of the lake itself, sustaining the fish population in the lake and the verdant flora along the entire watershed.

The fauna of the region have been distorted by human development so that what exists now is hardly what existed for so many years. While one can find the occasional coyote, you would be hard pressed to find a bear … and the original European settlers named the valley for a reason: in pursuit of some cattle thieves, Benjamin Wilson, an early pioneer, took 22 pairs of men into the canyon … and they came out with 22 bear hides. Needless to say, the population of California brown bears and grizzly bears has been severely reduce

The other feature of the natural environment worth mentioning is mining. After the gold rush in Northern California, several efforts were made to look for gold in the San Bernadino Mountains, starting in 1859. Bear Valley delivered some bear meat for the prospectors (those poor bears!), but the gold strike was found in Holcomb Valley, 5 miles to the north, not in Big Bear (Lucerne) Valley. That was probably best in the long run, as no significant ecological destruction occurred in Bear Valley, unless you count the extirpation of the Grizzly Bear in the early 1900s.

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Dangerous animals—bears

Truth is stranger than fiction. The most recent human fatality caused by a bear took place in the wilds of Ohio. Well, sort of the wilds—just outside of Cleveland.

It seems that a young man, Brent Kandra, was tending to a captive bear when the bear attacked and killed him. The bear was owned by a man who has kept exotic animals for display in the past, and the event has sparked debate about the wisdom, and regulation, of large exotic animals being kept by private individuals (Associate Press 2010).

Whether in a cage or in the wild, bears are undeniably dangerous animals. This is the next in our series exploring dangerous animals. Unlike most of the other species we have looked at whose danger to humans is really more imagined than real, bears do come in contact with humans with some regularity, sometimes with unfortunate consequences.

In North America there are three bear species: the black bear (Ursus americanus); the brown bear (Ursus acrtos); and the polar bear (Ursus maritimus).

Black bear

Black bear in the Canadian Rockies

Like so many common names, the name black bear is really not very good since the animals are often many other colors than black. The fur comes in shades of blond, black, brown, cinnamon, and gray. Interestingly, the bears tend to be black in the eastern forests, and more color variation is introduced as you survey the populations to the west, such that in California most of the bears are brown.

The black bear is the smallest of the bear species, and the most common, with the widest current distribution. They are found across Canada and south through New England into the Appalachian Mountains. There are populations in the Ozarks and in the southern states. In the west they can be found through the Pacific Northwest, and through the Rocky Mountains south into Mexico.

Black bears are generally shy and reclusive, but they can become accustom to humans, especially when they learn to associate human activity with food—through trash or handouts. In many backcountry areas where bears are common officials try to keep bears and people separate, but it is not always possible. Food storage is a great concern when camping. For example, while camping at one remote location in the Great Smoky Mountains campers were to hang their food from a cable over a stream.

Hanging a food pack over a stream in bear country

Hanging a food pack over a stream in bear country

Incorrectly hanging your bag could lead to a bad time.

Results of improperly hanging your food pack

Results of improperly hanging your food pack

Brown bears are similarly misnamed, although the color variation is less dramatic than their black bear cousins. There are several subspecies, or races, of brown bears that you may have heard of, dividing them into coastal Kodiak and inland grizzly populations, but they are all the same species.

Brown bear

Brown bear

While once much more wide-spread in their distribution, brown bears are limited today to Alaska and northwest Canada, with several populations in western United States parks such as Glacier and Yellowstone.

Encounters with polar bears are understandably rare given the remoteness of their habitat. (See why polar bears are sensitive to climate change.) Polar bears spend much of their time out on sea ice, hunting seals. However, unlike other bear encounters, most encounters between humans and polar bears seem to be motivated by predation—that is, the bear is looking to eat them.

Bear encounters do sometimes lead to injury or even fatalities, and as people spend more time in bear country, the chances for an encounter naturally go up. In encounters that go badly, injury is more common than fatality as bears most often attack when they feel threatened, and once the threat is over they tend to leave. Rarely do bears prey on humans as a food source, but it does happen. In general there are about 1.8 bear-caused fatalities per year (see Clark 2003, Gunther and Hoekstra 1998, Herrero and Fleck 1990, Herrero and Higgins 1999 for discussions).

Of the dangerous animals discussed in the series, bears are the ones that most people need to be aware of, and to think about when entering the woods. Do not do stupid things in bear country, like walk around imitating the sounds of animals to attract bears (yes, it has happened), improperly store your food, try to feed the bears, get too close while taking pictures, or tease or taunt the bears. Common sense and awareness that these majestic creatures are sharing our woods will ensure that your adventures will have only the typical amount of excitement.

Associate Press. 2010. Bear who mauled caretaker is put to death in Ohio. NPR. http://www.npr.org/templates/story/story.php?storyId=129321688.

Clark, D. 2003. Polar Bear – human interactions in Canadian National Parks, 1986-2000. Ursus 14(1):65-71.

Gunther, K. A., and H. E. Hoekstra. 1998. Bear-inflicted human injuries in Yellowstone National Park, 1970-1994. Ursus 10:377-384.

Herrero, S., and S. Fleck. 1990. Injury to people inflicted by Black, Grizzly or Polar Bears: recent trends and new insights. Bears: Their Biology and Management 8:25-32.

Herrero, S., and A. Higgins. 1999. Human injuries inflicted by bears in British Columbia: 1960 – 97. Ursus 11:209-218.

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Effects of climate change on polar bears

Polar bears (Ursus maritimus) are in the news again because of dire predictions for the coming decades on their population numbers. The effects of climate change have been predicted to impact the polar regions first and most dramatically according to most models, and indeed, it is at the poles where we are recording some of the most dramatic examples of climate change. Polar bears, being the largest of the living bear species, are charismatic and popular, and because of the likely impact that climate change will have on them they have become a poster species for the climate issue.

polar bear

Polar bear, Ursus maritimus.

In a recent interview bear expert Andrew Derocher predicted that one population of polar bears (western Hudson Bay) could see its numbers drop too low to be viable within three decades (Yale Environment 360 2010). We have explored polar bears and their populations in other posts. Here I want to examine why changes in sea ice and warmer periods are such a concern for polar bears.

Polar bears evolved relatively recently, diverging from an ancestral brown bear population about 150,000 years ago (Lindqvist et al. 2010). There is a unique population of brown bears that live on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska’s Alexander Archipelago. This population, called the ABC bears, is the closest brown bear relatives of the polar bears—early members of this population split off to live full time on the sea ice, evolving into the modern polar bear species. Thus, polar bears are an example of rapid mammalian evolution, undergoing morphologic changes such as elongated snouts, overall size changes, furry padded feet, and color changes, as well as social and metabolic changes to adapt to the rhythms of the arctic seasons.

It is their complex adaptations to living on the rugged ice that makes them most susceptible to changes in that habitat. They use the ice as a platform for hunting seals, as a habitat for finding mates and mating, and for traveling long distances. As the ice breaks up earlier in the spring, and re-freezes later in the winter, several weeks of prime hunting time are taken away from the polar bears. Today, they are able to spend almost three weeks less on the ice hunting than they were able to several decades ago. This is critical because after the ice breaks up for the year, the bears must fast until the next season, and longer times of open water means long fasting periods.

This can be critical for a female bear that must gestate her young, birth them, and begin to nurse them to a size large enough that they can accompany her onto the ice for hunting the next season. So, she is expending a great deal of energy in contributing to the growth of her young while fasting. If she did not build enough fat reserves the year before to withstand this metabolic marathon, she and her offspring will not survive into the following year. A few additional weeks of having to fast can be the difference between life and death.

The intimate connection that polar bears have evolved with their arctic habitat means that they are finely tuned to changes in that world. And with the effects of climate change appearing in the arctic regions first, they are in fact akin to the “canary in the coal mine,” a harbinger of things to come.

References:

Lindqvist, C., S. C. Schuster, Y. Sun, S. L. Talbot, J. Qi, A. Ratan, L. P. Tomsho, L. Kasson, E. Zeyl, J. Aars, W. Miller, Ó. Ingólfsson, L. Bachmann, and Ø. Wiig. 2010. Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear. Proceeding of the National Academy of Sciences.

Yale Environment 360. 2010. For Hudson Bay polar bears, the end is already in sight. http://e360.yale.edu/content/feature.msp?id=2293.

Additional related posts:
Polar Bear Populations
Public Opinion and a Geologic Perspective on the Effects of Global Warming
IPCC

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How big was the Giant Short-faced Bear?

The character of living things on land changed forever after the Cretaceous-Tertiary extinctions, 65 million years ago. The dinosaurs on land and the marine reptiles in the oceans went extinct, leaving way for mammals and birds to evolve into those niches once held by the “terrible lizards” (dinosaurs) and other giant reptiles.

Throughout the Cenozoic, sometimes “mammal-centrically” referred to as the Age of Mammals, these warm-blooded, fur-covered creatures diversified into a wide range of beasts, including humans. While many of the land mammals got very large, they never matched the recording-holding dinosaurs for superlative size on land.

The largest animals ever known to have lived actually evolved after the dinosaurs and are in fact alive today. An ancient lineage of mammals returned to the oceans and evolved into the modern whales. (See the note about the largest animals feeding upon the smallest).

People are always excited about the Carnivores, or meat-eating mammals. There is something about the dangerous and frightening that excites our primitive nerve centers, so the carnivores are among the most popular at the zoo. (Technical note here—the word carnivore is used in two ways. Carnivore (with a capital “C”) can refer to the class of mammals, the Carnivora, most of whom, but not all, are carnivores (with a lower case “c”), meaning they eat meat. So, not all carnivores are Carnivores, and not all Carnivores are carnivores. Got it? Good.) (Also, see the series on Dangerous Animals for additional exciting facts.)

For example, I recall a visit to the Cincinnati Zoo, and while watching the famed white tigers my young daughter was thrilled when one watched her intently and kept pace with her on the ground while she ran giggling high above on the wooden walkway. She thought that it was a special treat to have one of these magnificent animals take a special interest in her. She felt less special when we mentioned to her that the tiger may not have had cuddling on its mind.

Elsewhere (see related posts below) we have discussed the Giant Short-faced bear (GSFB), Arctodus simus, the great bear from the Ice Age that lived across North America. The GSFB is the largest mammalian Carnivore known, but just how big was it?

Recreation of the Giant Short-faced bear showing its size next to a human

Recreation of the Giant Short-faced bear showing its size next to a human

Many people have examined this question, and one study lays it out clearly (Christiansen 1999). Christiansen examined both the GSFB and its European cousin, the Cave Bear (Ursus spelaeus), another bear famous for its dimensions. Several skeletal measurements have been shown to correlate to overall body mass in mammals. It makes sense that large species have bones of greater relative diameter than small species, and the relationship is more or less linear. By making these measurements a very good estimate of body mass can be made for extinct mammals.

Christiansen used many skeletal measurements of modern carnivores with known body mass to create his linear equations and then plugged in both species of bears to see what the formulas suggested. The results of this study are clear—the GSFB far outweighed any of the modern bears and the cave bear.

These data suggested that a typical (average) GSFB would have weighed in at about 1,700 pounds. Given that there are exceptional individuals, it is estimated that a really large specimen could easily have weighed more than 2,200 pounds. In contrast, the cave bear seems to have a mean body mass of about 1,000 pounds, with exceptional individuals approaching the average for the GSFB.

To further help put this in context, below is a list of select modern and extinct animals and their average body masses. I threw in a couple of dinosaurs for good measure:

Animal

Body Mass (pounds)

Blue Whale

396,830

Brachiosaurus (extinct)

62,300

T. rex (extinct)

14,600

Giant Short-Faced Bear (extinct)

1,700

Kodiak Bear

1,090

North American Lion (extinct)

1,000

Cave Bear (extinct)

1,000

Polar Bear

900

African Lion

375

Indian Tiger

320

American Black Bear

230

Human

160

Leopard

115

Puma

100

Velociraptor (extinct)

98

Cheetah

86

Gray Wolf

78

Wolverine

27

Red Fox

12

No matter how you look at it, “Giant” is a good name for Arctodus!

Christiansen, P. 1999. What size were Arctodus simus and Ursus spelaeus (Carnivora: Ursidae)? Ann. Zool. Fennici 36(93-102).

Related posts:

GSFB, a Northern California Original

Denning behavior in the GSFB

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Denning behavior in the Giant Short-faced Bear

One of the most exciting things in paleontology to me is when we can begin to tease apart how extinct animals, animals that humans often never set eyes upon, lived their everyday lives. I am often amazed at how my colleagues can drill deep into questions that at first seem unanswerable; using creative ways to get answers from all the evidence that has survived, the bones, teeth, and sometimes trace fossils.

There are many examples of using the clues provided in the fossil record to come to better understand beasts from the past. In an earlier story, we looked at a disease process in Tyrannosaurus, and glimpsed how the mighty tyrant king could be brought down by a lowly protozoan. Here, we will explore some evidence for denning in the Giant Short-faced Bear (GSFB).

In a paper from several years ago Schubert and Kaufmann (2003) discussed the discovery of a GSFB in an Ozark cave. While incomplete, it is still one of the most complete specimens of the bear ever found. In addition to bones in partial articulation, they also found a thin layer of clay and minerals underneath the skeleton that preserves the remains of hair. Unfortunately, the hair is too deteriorated to tell us what color it was or exactly what its texture might have been, but its discovery is tantalizing.

This Ozark specimen is small compared to others of its species. There is a lot of evidence that there was a significant difference in size between male and female GSFBs. For example, at Rancho La Brea in southern California, both smaller and larger individuals have been found in contemporaneous deposits. It is easy to tell if the individuals are adult, so seeing large and small forms suggests two options: either there are two species, or there is one species with large and small individuals. It later is most likely. This is not surprising as all modern bears are sexually dimorphic.

Schubert and Kaufmann noted that over 1/3 of the known specimens of the GSFB come from caves, and that those specimens are smaller in general than the specimens found in open environments. (See the story about the type specimen, also found in a cave in northern California). It is logical to reason that the smaller individuals using the caves are predominately female.

Modern female bears are much more prone than males to den during periods of unfavorable conditions. And male bears are more likely to remain active throughout the year. It seems as if the GSFB followed a similar pattern—the females were using caves as denning sites, and were denning when they perished. In Cope’s original paper (1879), he called this new animal the cave bear of California—seems he was right.

From the accumulation of small bits of information we continuously piece together the lives of prehistoric beasts, slowly bringing them into sharper focus. That is the thrill of paleontology.

Cope, E. D. 1879. The cave bear of California. American Naturalist 13:791.
Schubert, B. W., and J. E. Kaufmann. 2003. A partial short-faced bear skeleton from an Ozark cave with comments on the paleobiology of the species. Journal of Cave and Karst Studies 65(2):101-110.

There are many other interesting facts here at Boneblogger. Just look around and enjoy.

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