Grizzly Bears – Why is this animal endangered and fast approaching extinction?

Review by Lindsay Willis

 

Grizzly bears (Ursus arctos horribillis)

Kingdom:         Animalia

Phylum:            Chordata

Class:               Mammaila

Order:              Carnivora

Family: Ursidae

Genus:              Ursus

Species:            U.arctos

Subspecies:      U. a. horribilis

 

The grizzly bear named after its silver-grey tips of hair, lives in the uplands of North America. It is a powerful large brown bear that is on the endangered species list.

 It ranges in weight from 180 to 680 kilograms, making it one of the largest animals in North America. The grizzly has a large distinguishable hump over the shoulders to aid in digging. It ranges in color from brown to yellowish brown to almost a black color depending on its diet.

Grizzly bears have a widespread and solitary habitat. They have the largest roaming area of all the species of bears. The females range from 200 to 600 square kilometers and the males range from 900 to 1800 square kilometers. They range mainly in the mountains, forest, and near river banks. Unfortunately these days they are ranging more and more out of the wilderness in search of food, coming more in contact with humans.

They are carnivores and will eat almost anything. Their diet mostly consists of berries, grasses, herbs, nuts, animal carcass, fish, small animals, and some large animals such as moose or elk. Due to their large size and that they are hibernating creatures; they spend most of their time in search of food or eating.

These bears have a lifespan of usually 15 to 30 years in the wild. The breeding season is the summer months, which is the only time that the males and females are together. The mother bears have their cubs in the winter during hibernation, usually having 2 cubs. The cubs usually stay with their mother until they are 2 years old and then will venture out onto their own.

 

Fast Approaching Extinction

 

Grizzly bears have few enemies in the wild yet they are fast approaching extinction. The only enemies they have are other bears and humans. Humans thus being the main contributor to the grizzly’s dwindling population. They are hunted as game through out North America legally and illegally. Their habitats are also being invaded by human populations. Not just by people coming and living in these areas but also by logging, oil and gas and fire management. Humans are also impacting the grizzly population by other methods such as the closer of the garbage dumps in Yellowstone National park.

Their population is struggling to find food in this changing habitat because they are forced to live in smaller areas thus resulting in less food for the bears. They are also running into more human contact in these smaller areas and forced to change the food they eat and the way they live. All of which is contributing to the stress of survival for the grizzlies. This is not only affecting the grizzlies of today but is affecting the grizzlies of tomorrow.

 

A study done on the “Environmental stress and developmental stability” of grizzly’s shows that changes in the bears ecosystem greatly affects not only their survival but also the asymmetry of their development and their young’s as well. The study shows that a stressful event or an environmental change greatly affects their asymmetry and development of morphological traits. This then results in grizzlies with developmental, reproductive, and growth asymmetry.

The grizzly bears in Yellowstone National Park where mainly eating the garbage at the park dumps, and when the park decided to close off the dumps it had a major affected on the bears.  By studying the fluctuating asymmetry of the bear’s denotation before and after the closure they are able to see that a significant environmental stress affects the bear’s development. This can help researches study bear’s in other parks and in the wild. Because like the bear’s in the park the wild bear’s are having to change their eating habits due to human impact and may be having the same asymmetry changes as the bears in Yellowstone. So they can study if the changes of the environment are affecting bear’s and then with the results be able to try and change the stress that is causing this. Thus resulting in less fluctuating asymmetry and hopefully less bear’s becoming extinct.

 This study helps show that the environmental stress is affecting the bear’s. It also shows that it can help in measuring the genes and understanding the affects asymmetry has on bear’s.

 This type of study does however take a long time to do, and there can be more than one factor affecting the stress on the bear’s. It is also hard to do a similar study on wild bears because they need to look at the dentition of them, causing a problem in their methods.

The focus needs to be on having humans impact the bear’s less and the main focus should be on creating a solution.  Like having parks for them to live freely in and trying to keep human contact to a minimum. Illegal and legal hunting also needs to stop for the bear’s population to increase and thus become off the endangered list. Humans may also be indirectly affecting the bear’s such as humans affecting the fish population in the bear’s habitat. Thus creating food problems for the bear’s who depend on eating these fish.

The main problem is these changes need to be done now. The population every year is decreasing and will only continue to decrease if a major change does not occur. The grizzly bear usually only have 2 cubs each year thus making it hard for them to maintain their population on their own let alone without all the human impact. Humans need to be more aware of the impact they are putting on the bear’s; by doing this it will not only help save the bear’s it will help save the humans being killed by the bears. Thus creating a place where both the bear’s and humans can live for many generations to come.

 

Literature Cited

 

Badyaev, Alexander. Division of Biological Science. (1998) Environmental stress and developmental stability in dentition of Yellowstone Grizzly Bears.

Behavior Ecology Vol. 9. No. 4:  339-344

 

http://www.canadianrockies.net/Grizzly/pophabvia.html

The Grizzly Bear of The Central Rockies Ecosystem