Grizzly Bear - Brody Gill

GRIZZLY BEAR (Ursus Arctos Horribilis)

By, Brody Gill

Descriptions and Ecology

Overview

The Grizzly Bear, often called the North American Brown Bear, is a subspecies of the Brown Bear (Ursus Arctos) that can reach over 10’ tall and weigh several hundred pounds. They are typically larger and more aggressive than the average Brown Bear with large concave faces and a distinct hump above their shoulders. Their name comes from their long, white tipped hair that gives them a “grizzled” look. Most Grizzlies are dark brown, but their coat can often range from being near black to a light cream color. They also have sharp claws that can grow to 4 inches long which help them with digging and catching fish. However, Grizzly Bears are omnivores and like to feast on things such as berries and salmon. When their food supply gets low, Grizzlies go into hibernation for as long as six months.

Habitat

The Grizzly Bear has historically roamed all over the western half of North America. Ranging from Mexico to Alaska and from the Pacific Coast to as far east as the Mississippi River. Furthermore, they have a large range of habitats they like to occupy. Places such as: artic barren grounds, prairies, foothill grasslands, and thick temperate rainforest. Grizzly Bears generally have a home territory that they mostly stick around, however, their territories often overlap with other bears’ territories. Most male Grizzlies have a larger range of territory than females do, allowing males to take advantage of the best food options in their territory.

Social Structure

Grizzly Bears are very much a K-Selected species, meaning that they have only a few offspring a year, take considerable care of their young, are large bodied, have a long life expectancy, etc. While they do not usually live in groups, Grizzly Bears can be seen around other bears when the food supply is abundant. They are generally solitary mammals that have a territory they range. Males often “rub” trees leaving their hair and scent on the tree to show where their territory is so females can more easily find them come mating time. Grizzlies have one of the slowest reproductive rates waiting until four or five years old before they can reproduce. Females are very protective of their young for two or three years, often becoming much more aggressive during this time.

Diet

Most animals at the top of the food chain are mainly carnivores. However, while Grizzlies are on top of the food chain, they are omnivores meaning that they both eat meat and vegetation. Their choice of food varies widely, including: roots, berries, fungi, grasses, insects, elk, deer, salmon, trout, and dead animals. In the spring, Grizzlies generally like to feast on any meet they can find to give them protein. During the summertime, they try to eat several types of forages or fruits. Finally, in the fall, before they go into hibernation, they try to gain as much weight as possible by eating roots and nuts. Although, they have a vast variety of food they will eat, vegetation consists of about 90% of their diet. Their diet also helps the ecosystems that they live in by regulating grazing and populations of other animals.

Population Changes

Grizzly Bears have always been a distinct and famous species in the United States, even appearing on the California State flag. In the 1800’s, there were reportedly over 50,000 Grizzly Bears that lived in the United States alone. Today, there is less than two percent of the number of Grizzlies reported in the 1800’s. This is a product of climate change, human conflicts, and habitat destruction. They were originally listed as a threatened species in 1975 when only 800 to 1000 Grizzlies were estimated remaining in the lower 48 states. In the greater Yellowstone Ecosystem, there were less the 150 total bears through the 1970’s. Once the recovery plan was implemented, it wasn’t until the 1990’s that Grizzly Bear populations showed any form of growth. In 2014, their population in the Greater Yellowstone Ecosystem reached 757 but then fell in 2016 to 690. These numbers are thought to represent the species’ population in the lower 48 states today.  

Geographic Changes

As said above, Grizzly Bears once roamed most of North America. However, throughout history, their geographic range in which they live has shrunk considerably as seen in the graph on the right. Today, they can only be seen in a couple of states in the lower 48 states where they are on the endangered species list. Most of the population of Grizzly Bears live in the Greater Yellowstone Ecosystem. However, they do live in other parts of Montana, Wyoming, Idaho and even a few have been spotted in Washington. The largest reason that bears have been extirpated from their historic territories is primarily because of humans. Through human development and conflict, to habitat destruction, and of course climate change, bears have had to relocated to find sustainable food and habitat for them to live in.  

Listing Date & Type

The Grizzly Bear was officially listed as a threatened species in the lower 48 states on July 28, 1975. However, there was no official recovery plan for the species until 1993. Until this time, Grizzly Bears populations had been steadily declining. In 2003, the recovery plan goals issued from 1993, had been met for six straight years. In 2006, there was a revised recovery plan for the Grizzly Bear issued. After this recovery plan went into effect, Grizzly Bears bounced back and forth from being on the “Threaten Species” list in several controversial lawsuits. As of March 2017, they are no longer considered a threatened species in the Greater Yellowstone Ecosystem, but still are in the rest of the lower 48 states.

Cause of Listing

Some of the initial causes of Grizzly Bears being listed on the “Threatened Species” list is through human conflict. This includes things such as human development and habitat destruction. During the times that Grizzly Bear populations were declining, humans were developing more land to put houses on in rural areas. This being their home, Grizzlies would often start coming up to house to dig in their garbage or dig in people’s gardens. People soon began to try to get rid of the bears close to their houses to keep it safe and clean. This also plays a part in habitat destruction. All the houses and infrastructure created in rural area where the bears liked to live created fewer spots for the bears to habitat. This is the largest reason the Grizzly Bear’s habitat changed so much throughout history and eventually affected their population.  

Continuing Threats

Grizzly Bears still are affected by the same human conflicts that originally got them on the “Threatened Species” list. However, the largest threat to the Grizzly Bear population today is climate change. With the temperatures around the world getting warmer, they are forced into smaller territories. Furthermore, much of their food supply is also being affected by climate change. Things such as White Bark Pines and fresh water Salmon are some of the Grizzly Bears most vital source of food. The warming temperatures are directly affecting these species and will cause a shortage in the food supply for bears.

Recovery Plan

The latest Grizzly Bear Recovery Plan indicates that its objectives are to delist the species as threatened and have a sustainable population. Some of the actions that it lists that would help with doing this are to: minimize human conflict, limit habitat loss or degradation, improve habitat and security, understand relationship between density and habitat value, develop techniques to move bear populations, improve public relations, and continue research. They estimate that the whole cost of implementing the recovery plan would be about $26,000,000! The Grizzly Bear species can range on a vast variety of landscapes, so it is estimated that it could take 30 or 40 years for some bear populations to reach the objective. The plan has funded several Grizzly Bear recovery zones in the ecosystems that they are native to. It also plans on using radio collars and other tracking devices to be able to monitor small populations of Grizzlies to better understand their normal behavior and keep them secure. By monitoring female reproductive rates and cycles, bear management groups can assume whether the population is sustainable. This will occur in six-year study periods. Also, they will monitor how much land they need to keep a sustainable population. It is estimated that each bear’s home range is about 1000-1500 square miles. They will also monitor the habitat richness and variability to make sure it is sustainable for the bears. Furthermore, they will also look at how their genetic diversity can be promoted between ecosystems. By possibly transporting or helping bears migrate between ecosystems, they can improve this. Bear management groups hope that by protecting the Grizzly Bear as much as possible, since it is at the top of the food chain, that it could help enrich the ecosystem they live in to its most sustainable state.

What Can You Do?

Some of the simplest things can help the Grizzly Bear population tremendously. Besides being aware of your ecological footprint to help with climate change, the best thing you can do to help with threatened species, like the Grizzly Bear, is to spread the word. When people encounter bears, contact your local Game Warden or Animal Control to allow them to deal with the bears. You can even install such things as electric fences so the bears stay away from your house. However, the best thing you can do for all endangered species, is spread awareness and be cognizant of your ecological footprint to help with climate change.

Other Resources

Listed below are some website that can help you learn more about Grizzly Bears and how you can help them!

National Parks Service: www.nps.gov

U.S. Fish and Wildlife Service: www.fws.gov

Defenders of Wildlife: www.defenders.org

get BEAR SMART society: www.bearsmart.com

Works Cited

“Bear Social Structure.” BioExpedition. 2017. Web. 2017.

Chagares, Jim. “Grizzly Bear.” Defenders of Wildlife. 2017. Web. 2017.

Keeler, Leo. “Grizzly Bear.” Earth Justice. 2017. Web. 2017.

“National Parks Service.” United States Department of the Interior. 2017. Website. 2017.

“North America’s Bears.” get BEAR SMART society. 2017. Web. 2017.

Servheen, Dr. Christopher. “Grizzly Bear Recovery Plan.” US Fish and Wildlife Service. Natural Science 312. University of Montana. 2006. Print. 2017.