Yellowstone Handbook 2019
Wildlife - Mammals
Yellowstone Resources and Issues Handbook. Published by the National Park Service (NPS).
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. 176 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. 178 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