![]() | Yellowstone Handbook 2019Wildlife - Mammals |
Yellowstone Resources and Issues Handbook. Published by the National Park Service (NPS).
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covered parks
Yellowstone National Park has abundant and diverse wildlife. A bald eagle and a golden eagle land on an elk
carcass killed by the Slough Creek wolf pack near the Lamar River. Surrounded by ravens,
Wildlife
WILDLIFE
Yellowstone’s abundant and diverse wildlife are as famous as its geysers. Habitat preferences and seasonal
cycles of movement determine, in a general sense,
where a particular animal may be at a particular time.
Early morning and evening hours are when animals
tend to be feeding and are more easily seen. But remember that the numbers and variety of animals you
see are largely a matter of luck and coincidence.
Wild animals, especially females with young, are
unpredictable and dangerous. Keep a safe distance
from all wildlife. Each year a number of park visitors
are injured by wildlife when approaching too closely.
Approaching on foot within 100 yards (91 m) of bears
or wolves, or within 25 yards (23 m) of other wildlife is prohibited. Please use roadside pullouts when
viewing wildlife. Use binoculars or telephoto lenses
for safe viewing and to avoid disturbing wildlife.
By being sensitive to its needs, you will see more of
an animal’s natural behavior and activity. If you cause
an animal to move, you are too close. It is illegal to
willfully remain near or approach wildlife, including
birds, within any distance that disturbs or displaces
the animal.
FREQUENTLY ASKED QUESTION:
Where can I see wildlife?
It helps to know the habits and migration patterns of the
animals you want to see and the habitats in which they
live. For example, bighorn sheep are adapted to live on
steep terrain, so you might see them on cliffs in the Tower
area. Osprey eat fish, so you would expect to see them
along rivers. Bison graze on grasses and sedges, and mate
in August, so you are likely to see them in big, noisy herds
in the Hayden and Lamar valleys.
Hydrothermal basins provide important habitat for wildlife.
For example, some bison live in the Old Faithful area yearround. In the winter, they take advantage of the warm
ground and thin snow cover. Both black and grizzly bears
visit these areas during the spring when winter-killed
animals are available. Rangers at the visitor centers can tell
you where wildlife have been seen recently.
Wildlife 175
Yellowstone is home to the largest concentration of mammals in the lower 48 states. Here, bison and elk graze
on the northern range.
WILDLIFE
Mammals
Yellowstone is home to the largest concentration of
mammals in the lower 48 states. In addition to having
a diversity of small animals, Yellowstone is notable
for its predator–prey complex of large mammals, including eight ungulate species (bighorn sheep, bison,
elk, moose, mountain goats, mule deer, pronghorn,
and white-tailed deer) and seven large predators
(black bears, Canada lynx, coyotes, grizzly bears,
mountain lions, wolverines, and wolves).
The National Park Service’s goal is to maintain
the ecological processes that sustain these mammals and their habitats while monitoring the changes
taking place in their populations. Seasonal or migratory movements take many species across the park
boundary where they are subject to different management policies and uses of land by humans.
Understanding the links between climate change
and these drivers will be critical to informing the
ecology and management of Yellowstone’s wildlife in
the years to come.
More Information
Curlee, A.P. et al., eds. 2000. Greater Yellowstone predators: ecology and conservation in a changing landscape.
Proceedings of the Third Biennial Conference on the
Greater Yellowstone Ecosystem. Jackson, WY: Northern
Rockies Conservation Coop.
Garrott, R. et al., editors. 2009. The ecology of large mammals in Central Yellowstone. San Diego: Academic Press.
Ruth, T. et al. 2003. Large carnivore response to recreational
big-game hunting along the Yellowstone National Park
and Absaroka-Beartooth Wilderness boundary. Wildlife
Society Bulletin. 31(4):1–12.
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Yellowstone Resources and Issues Handbook, 2019
Quick Facts
Yellowstone is home to the largest concentration of
mammals in the lower 48 states.
•
67 different mammals live here, including many small
mammals.
•
As of 2017, an estimated 718 grizzly bears live in the
Greater Yellowstone Ecosystem.
•
Black bears are common.
•
Gray wolves were restored in 1995. As of January
2017, 97 live primarily in the park.
•
Wolverine and lynx, which require large expanses of
undisturbed habitat, live here.
•
Seven native ungulate species—elk, mule deer, bison,
moose, bighorn sheep, pronghorn, and white-tailed
deer—live here.
•
Nonnative mountain goats have colonized northern
portions of the park.
Schullery, P. and L. Whittlesey. 1999. Early wildlife history of
the Greater Yellowstone Ecosystem. Report, available in
Yellowstone Heritage and Research Center Library.
Streubel, D. 2002. Small mammals of the Yellowstone
Ecosystem. Juneau, Alaska: Windy Ridge Publishing.
Feldhamer, G.A., B.C. Thompson, and J.A. Chapman, eds.
2003. Wild mammals of North America: Biology, management, and conservation. Baltimore: Johns Hopkins
University Press.
White, P. J., Robert A. Garrott, and Glenn E. Plumb.
2013. Yellowstone’s wildlife in transition. Cambridge,
Massachusetts: Harvard University Press.
Bears
Yellowstone is home to both grizzly bears (above)
and black bears. Safe traveling in bear country begins
before you get on the trail.
especially when human food is present, makes the
presence of a viable grizzly population a continuing challenge for its human neighbors in the Greater
Yellowstone Ecosystem.
Population
Grizzly Bears
The Greater Yellowstone Ecosystem and northwest
Montana are the only areas south of Canada that
still have large grizzly bear (Ursus arctos horribilis)
populations. Grizzly bears were federally listed in the
lower 48 states as a threatened species in 1975 due
to unsustainable levels of human-caused mortality,
habitat loss, and significant habitat alteration. Grizzly
bears may range over hundreds of square miles, and
the potential for conflicts with human activities,
The estimated Greater Yellowstone Ecosystem grizzly
bear population increased from 136 in 1975 to a peak
of 757 (estimated) in 2014. The 2018 population estimate is 712 bears. The bears have gradually expanded
their occupied habitat by more than 50%. As monitored by the Interagency Grizzly Bear Study Team,
the criteria used to determine whether the population within the Greater Yellowstone Ecosystem has
recovered include estimated population size, distribution of females with cubs, and mortality rates. An
Grizzly Bears
Number in Yellowstone
Approximately 150 with home ranges
wholly or partially in the park.
As of 2018, 712 estimated in greater
Yellowstone.
Where to See
Dawn and dusk in the Hayden and
Lamar valleys, on the north slopes of
Mt. Washburn, and from Fishing Bridge
to the East Entrance.
Size and Behavior
•
Males weigh 200–700 pounds,
females weigh 200–400 pounds;
adults stand about 3½ feet at the
shoulder.
•
May live 15–30 years.
•
Grizzly bears are generally 1½ to 2
times larger than black bears of the
same sex and age class within the
same geographic region, and they
have longer, more curved claws.
•
Mate in spring, but implantation of
embryos is delayed until fall; gives
birth in the winter to 1–3 cubs.
•
Considered super hibernators.
•
Lifetime home range: male,
800–2,000 square miles, female,
300–550 square miles.
•
Agile; can run up to 40 mph.
•
Can climb trees, but curved claws
and weight make this difficult.
Can also swim and run uphill and
downhill.
Status
•
The US Fish and Wildlife Service
announced their decision to
remove grizzly bears from the
federal Threatened species list in
June 2017.
•
Adapted to life in forest and
meadows.
•
Food includes rodents, insects, elk
calves, cutthroat trout, roots, pine
nuts, grasses, and large mammals.
•
Scientists and managers believe
the grizzly population is doing
well. Grizzlies are raising cubs in
nearly all portions of the greater
Yellowstone area and dispersing
into new habitat. Currently, they
occupy 20,522 square miles in the
Greater Yellowstone Ecosystem.
Wildlife 177
WILDLIFE
Yellowstone is home to two species of bears: grizzly
bears and black bears. Of the two species, black bears
have a much larger range across the United States.
The grizzly bear is typically larger than the black bear
and has a large muscle mass above its shoulders; a
concave, rather than straight or convex, facial profile; and much more aggressive behavior. The grizzly
bear is a subspecies of brown bear that once roamed
large swaths of the mountains and prairies of the
American West. Today, the grizzly bear remains in a
few isolated locations in the lower 48 states, including Yellowstone. In coastal Alaska and Eurasia, the
grizzly bear is known as the brown bear.
Visitors should be aware that all bears are potentially dangerous. Park regulations require that people
stay at least 100 yards (91 m) from bears (unless safely
in your car as a bear moves by). Bears need your concern, not your food; it is against the law to feed any
park wildlife, including bears.
WILDLIFE
estimated 150 grizzly bears occupy ranges that lie
partly or entirely within Yellowstone. The number
of females producing cubs in the park has remained
relatively stable since 1996, suggesting that the park
may be at or near ecological carrying capacity for
grizzly bears.
There were 69 known or probable grizzly bear
mortalities in the Greater Yellowstone Ecosystem
in 2018 (51 in the Designated Management Area),
including 10 adult females, 21 adult males, and 14
dependent young. There was one known grizzly bear
death inside the park: an adult female of unknown
age was found near the Lamar River. Cause of death
is unknown, but was likely intra-specific conflict.
On August 23, 2018—for the first time in three
years—a bear attack was reported in Yellowstone
National Park. A family of four hikers from
Washington state had a surprise encounter with an
adult female grizzly bear on the Divide Trail. The sow
charged out of the vegetation and knocked a 10-yearold boy to the ground. The child suffered an injured
wrist, puncture wounds to the back and wounds
around the buttocks. The parents successfully deployed bear spray and the bear left the scene. Further
investigation determined that the female grizzly was
defending at least one cub-of-the-year or yearling
bear and no effort was made to search for them.
FREQUENTLY ASKED QUESTIONS:
Where are the bears?
People who visited Yellowstone prior to the 1970s often
remember seeing bears along roadsides and within
developed areas of the park. Although observing these
bears was very popular with park visitors, it was not
good for people or bears. In 1970, the park initiated an
intensive bear management program to return the grizzly
and black bears to feeding on natural food sources and to
reduce bear-caused human injuries and property damage.
The measures included installing bear-proof garbage cans
and closing garbage dumps in the park.
Bears are still seen near roads and they may be seen
occasionally in the wild. Grizzly bears are active primarily
at dawn, dusk, and night. In spring, they may be seen
around Yellowstone Lake, Fishing Bridge, Hayden and
Lamar valleys, Swan Lake Flats, and the East Entrance.
In mid-summer, they are most commonly seen in the
meadows between Tower–Roosevelt and Canyon, and in
the Hayden and Lamar valleys. Black bears are most active
at dawn and dusk, and sometimes during the middle of
the day. Look for black bears in open spaces within or near
forested areas. Black bears are most commonly observed
between Mammoth, Tower, and the Northeast Entrance.
Are grizzly bears considered threatened
or endangered?
The Yellowstone grizzly population is listed as a federal
Threatened Species as of a court decision on September
24, 2018. Regardless of its listing status, scientists will
continue to monitor the long-term recovery goals for
grizzly bears.
Description
The grizzly bear’s color varies from blond to black,
often with pale-tipped guard hairs. In the Greater
Yellowstone Ecosystem, many grizzly bears have a
light-brown girth band. However, the coloration of
black and grizzly bears is so variable that it is not a
reliable means of distinguishing the two species.
Bears are generally solitary, although they may
tolerate other bears when food is plentiful. Grizzlies
have a social hierarchy in which adult male bears
dominate the best habitats and food sources, generally followed by mature females with cubs, then by
other single adult bears. Subadult bears, who are just
learning to live on their own away from mother’s
protection, are most likely to be living in poor-quality
habitat or in areas nearer roads and developments.
Thus, young adult bears are most vulnerable to
danger from humans and other bears, and to being
conditioned to human foods. Food-conditioned
bears are removed from the wild population.
Diet
When combined with other characteristics, a grizzly
bear’s shoulder hump can help distinguish it from a
black bear.
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Yellowstone Resources and Issues Handbook, 2019
Bears are generalist omnivores that can only poorly
digest parts of plants. They typically forage for plants
when they have the highest nutrient availability and
Identify Grizzly Bears and Black Bears
Grizzly Bear
Black Bear
•
Rump lower than shoulders.
•
Rump higher than shoulders.
•
Shoulder hump present.
•
No shoulder hump.
•
Short, curved, claws for climbing.
•
Long claws for digging.
front
WILDLIFE
4.5 inches
5.25 inches
digestibility. Although grizzly bears make substantial
use of forested areas, they make more use of large,
non-forested meadows and valleys than do black
bears. The longer, less curved claws and larger shoulder muscles of the grizzly bear makes it better suited to
dig plants from the soil and rodents from their caches.
Grizzly bear food consumption is influenced by
annual and seasonal variations in available foods.
Over the course of a year, army cutworm moths,
whitebark pine nuts, ungulates, and cutthroat trout
are the highest-quality food items available. In total,
grizzly bears in the Greater Yellowstone Ecosystem
are known to consume at least 266 species of plant
(67%), invertebrate (15%), mammal (11%), fish, and
fungi. They will eat human food and garbage where
they can get it. This is why managers emphasize that
keeping human foods secure from bears increases
the likelihood that humans and bears can peacefully
coexist in greater Yellowstone.
Bears spend most of their time feeding, especially
during “hyperphagia,” the period in autumn when
they may gain more than three pounds per day until
they enter their dens to hibernate. In years and locations when whitebark pine nuts are available, they
are the most important bear food from September
back
7 inches
10 inches
front
back
through October. However, not all bears have access to whitebark pine nuts, and in the absence of
this high-quality food, the bear’s omnivory lets them
turn to different food sources. Fall foods also include pondweed root, sweet cicely root, grasses and
sedges, bistort, yampa, strawberry, globe huckleberry,
grouse whortleberry, buffaloberry, clover, horsetail,
dandelion, ungulates (including carcasses), ants, false
truffles, and army cutworm moths.
From late March to early May, when they come
out of hibernation, until mid May, a grizzly bear’s diet
primarily consists of elk, bison, and other ungulates.
These ungulates are primarily winter-killed carrion
(already dead and decaying animals), and elk calves
killed by predation. Grizzly bears dig up caches made
by pocket gophers. Other items consumed during
spring include grasses and sedges, dandelion, clover,
spring-beauty, horsetail, and ants. When there is an
abundance of whitebark seeds left from the previous
fall, grizzly bears will feed on seeds that red squirrels
have stored in middens.
From June through August, grizzly bears consume
thistle, biscuitroot, fireweed, and army cutworm moths
in addition to grasses and sedges, dandelion, clover,
spring-beauty, whitebark pine nuts, horsetail, and ants.
Wildlife 179
WILDLIFE
By April 2013, this bear had emerged from hibernation
and was searching for food to replenish lost body mass.
Grizzly bears are rarely able to catch elk calves after
mid-July. Starting around mid-summer, grizzly bears
begin feeding on strawberry, globe huckleberry, grouse
whortleberry, and buffaloberry. By late summer, false
truffles, bistort, and yampa are included in the diet as
grasses and other plants become less prominent.
Hibernation
Bears’ annual denning behavior probably evolved in
response to seasonal food shortages and cold weather.
Bears hibernate during the winter months in most of
the world. The length of denning depends on latitude,
and varies in duration from a few days or weeks in
Mexico to six months or more in Alaska. Pregnant females tend to den earlier and longer than other bears.
Grizzly bear females without cubs den on average for
about five months in Greater Yellowstone.
Grizzly bears will occasionally re-use a den in
greater Yellowstone, especially those located in natural cavities like rock shelters. Dens created by digging, as opposed to natural cavities, usually cannot be
reused because runoff causes them to collapse in the
spring. Greater Yellowstone dens are typically dug
in sandy soils and located on the mid- to upper-onethird of mildly steep slopes (30–60°) at 6,562–10,000
feet (2,000–3,048 m) in elevation. Grizzly bears often
excavate dens at the base of a large tree on densely
vegetated, north-facing slopes. This is desirable in
greater Yellowstone because prevailing southwest
winds accumulate snow on the northerly slopes and
insulate dens from sub-zero temperatures.
The excavation of a den is typically completed in
3–7 days, during which a bear may move up to one
ton of material. The den includes an entrance, a short
tunnel, and a chamber. To minimize heat loss, the den
180
Yellowstone Resources and Issues Handbook, 2019
entrance and chamber are usually just large enough
for the bear to squeeze through and settle into; a
smaller opening will be covered with snow more
quickly than a large opening. After excavation is complete, the bear covers the chamber floor with bedding
material such as spruce boughs or duff, depending on
what is available at the den site. The bedding material
has many air pockets that trap body heat.
The body temperature of a hibernating bear
remains within 12°F (22°C) of their normal body
temperature. This enables bears to react more quickly
to danger than hibernators who have to warm up
first. Because of their well-insulated pelts and their
lower surface area-to-mass ratio compared to smaller
hibernators, bears lose body heat more slowly, which
enables them to cut their metabolic rate by 50–60%.
Respiration in bears, normally 6–10 breaths per minute, decreases to 1 breath every 45 seconds during
hibernation, and their heart rate drops from 40–50
beats per minute during the summer to 8–19 beats
per minute during hibernation.
Bears sometimes awaken and leave their dens during the winter, but they generally do not eat, drink,
defecate, or urinate during hibernation. They live
off of a layer of fat built up prior to hibernation. The
urea produced from fat metabolism (which is fatal at
high levels) is broken down, and the resulting nitrogen is used by the bear to build protein that allows it
to maintain muscle mass and organ tissues. Bears may
lose 15–30% of their body weight but increase lean
body mass during hibernation.
Bears emerge from their dens when temperatures
warm up and food is available in the form of winterkilled ungulates or early spring vegetation. Greater
Yellowstone grizzly bears begin to emerge from their
den in early February, and most bears have left their
dens by early May. Males are likely to emerge before
females. Most bears usually leave the vicinity of their
dens within a week of emergence, while females with
cubs typically remain within 1.86 miles (3 km) of
their dens until late May.
Life Cycle
Grizzly bears reproduce slowly compared to other
land mammals. Females rarely breed before age
four, and typically become pregnant once every
three years. Grizzly and black bears breed from May
through July, and bears may mate with multiple partners during a single season. Because implantation of
a fertilized egg in the uterus is delayed, the embryo
Grizzly Bears and the Endangered Species Act
Grizzly Bears, Black Bears, and Wolves
Grizzly bears are more aggressive than black bears,
and more likely to rely on their size and aggressiveness to protect themselves and their cubs from
predators and other perceived threats. Their evolution diverged from a common ancestor more than
3.5 million years ago, but their habitats only began to
overlap about 13,000 years ago. Grizzly bears, black
bears, and gray wolves have historically coexisted
throughout a large portion of North America. The
behavior of bears and wolves during interactions
with each other are dependent upon many variables
including age, sex, reproductive status, prey availability, hunger, aggressiveness, numbers of animals,
and previous experience in interacting with the
other species. Most interactions between the species
involve food, and they usually avoid each other. Few
instances of bears and wolves killing each other have
been documented. Wolves sometimes kill bears, but
usually only bear cubs.
Wolves prey on ungulates year-round. Bears feed
on ungulates primarily as winter-killed carcasses, ungulate calves in spring, wolf-killed carcasses in spring
through fall, and weakened or injured male ungulates during the fall rut. Bears may benefit from the
On July 28, 1975, under the authority of the
Endangered Species Act, the US Fish and Wildlife
Service listed the grizzly bear in the lower 48 states
as “threatened,” in part, because the species was
reduced to only about 2% of its former range south
of Canada. Five or six small populations, totaling 800
to 1,000 bears, were thought to remain. The southernmost—and most isolated—of those populations
was in greater Yellowstone, where 136 grizzly bears
were thought to live in the mid-1970s. The goal of an
Endangered Species Act listing is to recover a species
to self-sustaining, viable populations that no longer
need protection. To achieve this goal, federal and
state agencies
• Stopped the grizzly hunting seasons in the
Greater Yellowstone Ecosystem.
• Established the Yellowstone grizzly bear recovery area (Yellowstone National Park, John D.
Rockefeller, Jr. Memorial Parkway, portions
of Grand Teton National Park, national forests
surrounding Yellowstone, Bureau of Land
Management lands, and state and private land
in Idaho, Montana, and Wyoming).
• Created the Interagency Grizzly Bear Study
Team to coordinate bear management among
Wildlife 181
WILDLIFE
does not begin to develop until late
November or December, about one
month after the mother has denned.
This appears to allow her to conserve energy until she enters her
den where, in late January or early
February, she gives birth to one or
two cubs, sometimes three, rarely
four. At birth the cubs are hairless
and blind, are about eight inches
(20 cm) long, and weigh from 8 to
12 ounces (224–336 g). The cubs do
not hibernate. They sleep next to
A grizzly bear sow with three cubs defends a carcass from wolves on
the sow, nurse, and grow rapidly. At
Alum Creek in Hayden Valley, 2010. Most interactions among the grizzly
bears, black bears, and wolves involve food. The species usually avoid
ten weeks, grizzly bear cubs weigh
each other.
from 10–20 pounds (4.5–9.0 kg).
Male bears take no part in raispresence of wolves by taking carcasses that wolves
ing cubs, and may actually pose a threat to younger
have killed, making carcasses more available to bears
bears. Grizzly bear cubs usually spend 2½, and
throughout the year. If a bear wants a wolf-killed
sometimes 3½, years with their mother before she or
a prospective suitor chases them away so that she can animal, the wolves will try to defend it; wolves usually
fail to chase the bear away, although female grizzlies
mate again. Females frequently establish their home
with cubs are seldom successful in taking a wolf-kill.
range in the vicinity of their mother, but male cubs
disperse farther.
WILDLIFE
the federal agencies and state wildlife managers; the team monitors bear populations and
studies grizzly bear food habits and behavior.
• Established the Interagency Grizzly Bear
Committee to increase communication and cooperation among managers in all recovery areas,
and to supervise public education programs,
sanitation initiatives, and research studies.
The Grizzly Bear Recovery Plan was established
in 1993 and revised in 2006. It has four demographic
and sustainable mortality goals for grizzly bears in
the Greater Yellowstone Ecosystem. This plan guides
management when the grizzly is on the Threatened
Species List. Bear managers use the Grizzly
Conservation Strategy when the grizzly is off the
Threatened Species List. The Conservation Strategy
is the long-term guide for managing and monitoring
the grizzly bear population and assuring sufficient
habitat to maintain recovery. It emphasizes coordination and cooperative working relationships among
management agencies, landowners, and the public
to ensure public support, continue the application
of best scientific principles, and maintain effective
actions to benefit the coexistence of grizzlies and humans. It incorporates existing laws, regulations, policies, and goals. The strategy has built-in flexibility:
• Grizzly–human conflict management and bear
habitat management are high priorities in the
recovery zone, which is known as the Primary
Conservation Area. Bears are favored when
•
•
•
•
•
grizzly habitat and other land uses are incompatible; grizzly bears are actively discouraged
and controlled in developed areas.
State wildlife agencies have primary responsibility to manage grizzly bears outside of
national parks, including bears on national forests; national parks manage bears and habitat
within their jurisdictions.
The grizzly bear population will be sustained at
or above 500 bears in the Greater Yellowstone
Ecosystem.
State and federal wildlife managers will continue to monitor the grizzly population and
habitat conditions using the most feasible and
accepted techniques.
Managers will remove nuisance bears conservatively and within mortality limits outlined
above, and with minimal removal of females;
they will emphasize removing the human cause
of conflict rather than removing a bear.
Outside the Primary Conservation Area, states
develop management plans, with input from
affected groups and individuals, that define
where grizzly bears are acceptable.
Legal Status of the Population
The grizzly bear population has grown robustly since
1983. The rate of growth has slowed somewhat in the
last decade, likely due to increased population density. Grizzlies are raising cubs in all portions of the
Management to Conserve Grizzly Bears
The Issue
The grizzly bear was listed as a
threatened species in 1975, which
required recovering the species to a selfsustaining population.
History
•
1993: A recovery plan is
implemented with three specific
recovery goals that have to be met
for six consecutive years.
•
•
182
2000: Draft Conservation Strategy
for the Grizzly Bear in the
Greater Yellowstone Ecosystem is
completed.
2002: Conservation Strategy is
approved after public comment
period—16,794 comments were
received. It will be implemented
when the grizzly is removed from
Threatened Species List.
•
2003: Recovery goals are met for
the sixth year in a row.
•
2005: US Fish and Wildlife Service
proposes removing the grizzly bear
from Threatened Species List.
•
•
•
2006: Grizzly Bear Recovery Plan
is modified to update methods
of estimating population size and
sustainable mortality.
2007: Greater Yellowstone grizzly
bear population is removed
from the Threatened Species
List. Conservation Strategy is
implemented.
2009: The population is returned to
Yellowstone Resources and Issues Handbook, 2019
the Threatened Species List.
•
2010: The US Fish and Wildlife
Service appeals the decision to
keep the grizzly bear on the
Threatened Species List.
•
2011: An appeals court rules
the grizzly bear remain on the
Threatened Species List.
•
2013: Yellowstone Ecosystem
subcommittee and Interagency
Grizzly Bear Study Team
recommend that grizzly bears be
removed from threatened status.
•
2017: The Fish and Wildlife
Service announces the removal
of Yellowstone grizzlies from the
Threatened Species List.
Grizzly Bear Recovery Plan: Population Monitoring Criteria (revised 2012)
Was the criteria met?
Population Objectives
2012
2013
2014
Estimated % of total mortality of independent-aged females not
to exceed 7.6%.
Estimated % of total mortality of independent-aged males not to
exceed 15%.
Estimated % of mortality from human causes for dependent
young not to exceed 7.6%.
Demographic objective of 48 females producing cubs annually.
(2006–2013)
N/A
N/A
N/A
Population estimate ≥ 500 bears in the recovery area.
(Criteria instituted in 2014)
2016
2017
2018
N/A
N/A
N/A
N/A
population remaining on the Threatened Species
List. The panel ruled in favor of the US Fish and
Wildlife Service on the issue of the Conservation
Strategy providing adequate regulations to conserve
bears after delisting.
In June 2017, the US Fish and Wildlife Service announced its decision to remove the grizzly bear from
threatened species status. That decision was vacated
by a court in September, 2018 and grizzly bears
were returned to Threatened status in the lower 48
states. Though management of the grizzly bears in
Yellowstone National Park changes little whether the
species is listed on the Threatened Species List or
not, the areas bordering and surrounding the park
will be managed by state agencies. Scientists will
continue to monitor the long-term recovery goals for
grizzly bears and strive to ensure the criteria are met.
Management of grizzly bears outside Yellowstone
National Park changes a great deal since they are no
longer on the Threatened Species List.
Wildlife 183
WILDLIFE
recovery zone. They have also dispersed into habitat
well outside of the recovery zone. Bears range south
into Wyoming’s Wind River Range, north of the park
through the Gallatin Range, and east of the Absaroka
Mountains onto the Plains.
For these reasons, and because the grizzly bear
population in the Greater Yellowstone Ecosystem
was determined to be a distinct population segment
that met all the population criteria for delisting, the
Greater Yellowstone grizzly population was removed
from the Threatened Species List in 2007 by the US
Fish and Wildlife Service. Several groups advocating
to re-list the bears as a threatened population filed
lawsuits challenging the decision.
In September 2009, a federal district judge overturned the delisting ruling, placing grizzly bears
back on the Threatened Species List claiming: (1)
the Conservation Strategy that guides management
after delisting was unenforceable and non-binding
on state and federal agencies, and (2) that the US Fish
and Wildlife Service did not adequately consider the
impacts of the potential loss of whitebark pine nuts, a
grizzly bear food source.
In January 2010, the Department of Justice and
the US Fish and Wildlife Service filed an appeal in the
Ninth Circuit Court in San Francisco—contesting,
among other points, that the judge did not consider
information on whitebark pine provided in the US
Fish and Wildlife Service legal briefing, and should
have deferred to the opinion of federal experts to
interpret biology.
In November 2011