Chapter 8
Terrestrial Mammals

Terrestrial animals are animals that inhabit the land. Mammals are warm-blooded, breathe air, have hair at some point in their lives, give birth to live young (as opposed to laying eggs), and nourish their young by secreting milk.

The biggest cause of terrestrial mammalian decline and extinction in the twentieth-first century is habitat loss and degradation. As humans convert forests, grasslands, rivers, and wetlands for various uses, they relegate many species to precarious existences in small, fragmented habitat patches. In addition, some terrestrial mammals have been purposely eliminated by humans. For example, bison (buffalo), elk, and beaver stocks were severely depleted in the United States following colonization by European settlers. All three species were nearly hunted to extinction by the end of the 1800s. The disappearance of native large game had consequences on other species. Wolves and other predators began preying on livestock and became the subject of massive kill-offs by humans.

Some terrestrial mammal species have been imperiled, in part, because they are considered dangerous to human life. This has been the case for many bears, wolves, and mountain lions. Changing attitudes have led to interest in preserving all species, and conservation measures have allowed several terrestrial mammals to recover.

ENDANGERED AND THREATENED U.S. SPECIES

As of March 2006 there were sixty-seven species of terrestrial mammals in the United States listed under the Endangered Species Act (ESA) as endangered or threatened. (See Table 8.1.) Nearly all have an endangered listing, meaning that they are at risk of extinction. Most have recovery plans in place.

The imperiled species fall into nine broad categories:

• Bats
• Bears
• Canines—foxes and wolves
• Deer, caribou, pronghorns, and bighorn sheep
• Felines—jaguars, jaguarundis, lynx, ocelots, panthers, and pumas
• Ferrets
• Rabbits
• Rodents—beavers, mice, prairie dogs, rats, squirrels, and voles
• Shrews

Approximately $51 million was spent under the ESA during fiscal year 2004 to conserve imperiled terrestrial mammal species. Table 8.2 shows the ten species with the highest expenditures. The grizzly bear was the most expensive ($7.2 million), followed by the Indiana bat ($4.9 million), and the Louisiana black bear ($3.8 million).

Bats

Bats belong to the taxonomic order Chiroptera, which means "hand-wing." They are the only true flying mammals. There are more than 900 species of bats worldwide; however, most are found in warm tropical regions. Only about four dozen species inhabit the United States. They typically weigh less than two ounces and have wingspans of less than twenty inches. Most are insectivores, meaning that insects are their primary food source. Bats prefer to sleep during the day and feed after dusk. Biologists believe that bats are vastly underappreciated for their role in controlling nighttime insect populations.

As of February 2006 there were nine bat species in the United States listed by the U.S. Fish and Wildlife Service (FWS) as endangered or threatened: gray bat, Hawaiian hoary bat, Indiana bat, lesser long-nosed bat, little Mariana fruit bat, Mariana fruit bat, Mexican long-nosed bat, Ozark big-eared bat, and Virginia big-eared bat.

Bats are imperiled for a variety of reasons, including habitat degradation, disturbance of hibernating and maternity colonies, direct extermination by humans, and the indirect effects of pesticide use on insects. More than $8 million was spent under the ESA on imperiled bat

species during fiscal year 2004. More than half of the money ($4.9 million) was devoted to the Indiana bat.

INDIANA BAT

The Indiana bat is a medium-sized, brown-colored bat found throughout a region encompassing the mid-Atlantic states and into the Midwest. (See Figure 8.1.) There are nine caves considered prime hibernation spots (or hibernacula) for the species during the winter. The bats are very sensitive to any disturbances during hibernation. If they are awakened, they become agitated and waste precious energy flying around frantically. This can leave them too weak and malnourished to survive the remainder of the winter. In the springtime, adult females move to wooded areas near agricultural crops and form maternity colonies. Loss of suitable habitat due to deforestation has disrupted this natural process. In addition, the bats have a low reproductive rate, producing only one baby per year. This makes it difficult for their populations to grow.

During the 1800s some hibernacula became popular winter visiting spots for tourists, cave explorers, bat fanciers, and well-meaning researchers. These disturbances, along with removal of suitable maternity habitat, led to decreased numbers of Indiana bats. The U.S. Fish and Wildlife Service estimates that the species numbered close to one million individuals in 1967 when it was listed under the Endangered Species Act. As of 2003 that number had dropped to around 380,000. In 2002 winter tours were discontinued at the Wyandotte Cave in Indiana, a prime hibernacula for the bats. Biologists report that this measure has resulted in increased bat numbers in the cave.

Bears

Bears belong to the family Ursidae. Their furry bodies are large and heavy, with powerful arms and legs and short tails. For the most part they feed on fruits and insects, but they also eat meat.

As of February 2006 there were three bear species listed as endangered or threatened in the United States: the American black bear, the Louisiana black bear, and the grizzly bear. Many bears are endangered due to habitat loss. According to the U.S. Fish and Wildlife Service, bears have been eliminated from about 50% to 75% of their natural ranges. Some bears have been hunted because they are considered predatory or threatening, while others are hunted for sport.

More than $11 million was spent under the ESA on imperiled bear species during fiscal year 2004. More than half of this money was devoted to the grizzly bear.

GRIZZLY BEARS

Grizzly bears are large animals, standing four feet high at the shoulder when on four paws, and as tall as seven feet when upright. Males weigh 500 pounds on average but are sometimes as large as 900 pounds. Females weigh 350 pounds on average. Grizzlies have a distinctive shoulder hump, which actually represents a massive digging muscle. Their claws are two to four inches long.

The grizzly bear was originally found throughout the continental United States, but has now been eliminated from all but a handful of western habitats. The first recovery plan for grizzly bears was published by the Fish and Wildlife Service in 1982. A revised recovery plan was published in 1993. At that time the species was found in a few ecosystems as shown in Figure 8.2; however, the populations were considered distinct from one another. The grizzly bear has declined due primarily to aggressive hunting and habitat loss. It is listed as threatened under the Endangered Species Act, except in nonessential experimental populations in parts of Idaho and Montana.

The federal government has established recovery zones for the grizzly bear in Yellowstone National Park, the North Continental Divide, the Selkirk and Bitterroot Mountains in Idaho, the North Cascades, the San Juan Mountains in Colorado, and the Cabinet/Yaak area on the Canadian border. Recovery plans for this species are coordinated under the Interagency Grizzly Bear Committee, which was created in 1983 (http://www.fs.fed.us/r1/wildlife/igbc/).

In November 2005 the FWS proposed removing the Yellowstone National Park population from the list of endangered and threatened species. Biologists reported that the population had grown from only 200 to 300 individuals in the 1970s to more than 600 bears.

Canines

Canine is the common term used to describe a member of the Canidae family of carnivorous animals. This family includes wolves, foxes, coyotes, jackals, and domestic dogs.

As of February 2006 there were five fox species and two wolf species listed under the Endangered Species Act in the United States. More than $4 million was spent under the ESA during fiscal year 2004 on endangered wolves. Just over $3 million was appropriated for the preservation of endangered fox species.

WOLVES

Wolves were once among the most widely distributed mammals on Earth. Prior to European settlement, wolves ranged over most of North America, from central Mexico to the Arctic Ocean. Their decline has largely resulted from hunting. In 1914 Congress authorized funding for the removal of all large predators, including wolves, from federal lands. By the 1940s wolves had been eliminated from most of the contiguous United States. In 1973 the wolf, which had all but disappeared, became the first animal listed as endangered under the ESA. Two species of wolves exist in North America today, the gray wolf and the red wolf. Both are imperiled.

In 1991 Congress instructed the U.S. Fish and Wildlife Service to prepare an environmental impact report on the possibility of reintroducing wolves to habitats in the United States. Reintroductions began in 1995. Over a two-year period, sixty-six gray wolves from southwestern Canada were introduced to Yellowstone National Park and central Idaho.

Wolf reintroductions were not greeted with universal enthusiasm. Ranchers, in particular, were concerned that wolves would attack livestock. They were also worried that their land would be open to government restrictions as a result of the wolves' presence. Some ranchers said openly that they would shoot wolves they found on their property. Several measures were adopted to address the concerns of the ranchers. The most significant was that ranchers would be reimbursed for livestock losses from a compensation fund maintained by the Defenders of Wildlife, a private conservation group based in Washington, D.C. Defenders of Wildlife in The Bailey Wildlife Foundation Wolf Compensation Trust (http://www.defenders.org/wildlife/wolf/wolfcomp.pdf) state that between 1987 and 2005 the fund had paid out $543,905 to 431 ranchers, covering the losses of 1,378 sheep, 565 cattle, and sixty-one other animals killed by wolves.

Wolf introductions were legally challenged in 1997, when the American Farm Bureau Federation initiated a lawsuit calling for the removal of wolves from Yellowstone. The farm coalition scored an initial victory, but in January 2000 the Tenth Circuit Court of Appeals in Denver overturned the decision upon appeal by the U.S. Department of the Interior, the World Wildlife Fund, and other conservation groups.

Despite the concern of ranchers and livestock owners, a recovered wolf population in the Yellowstone Park area has only slightly reduced populations of cattle, sheep, elk, moose, bison, and deer. In fact, wolves weed out sick and weak animals, thus improving the overall health of prey populations. Wolf predation on herbivorous species also takes pressure off vegetation and produces carrion for an array of scavengers including eagles, ravens, cougars, and foxes. Finally, wolves have increased visitor attendance to Yellowstone National Park, generating an estimated $7-$10 million in additional net income each year.

The U.S. Fish and Wildlife Service issues an annual report on the status of gray wolf populations in the Northern Rocky Mountain states (Idaho, Montana, and Wyoming). The latest report covers calendar year 2005 (http://westerngraywolf.fws.gov/annualrpt05/2005_WOLF_REPORT_TOTAL.pdf). It places the population of gray wolves at 1,020 individuals, including seventy-one breeding pairs (an adult male and female raising two or more pups). A map of the entire wolf recovery area is shown in Figure 8.3. An historical breakdown of populations by area is shown in Figure 8.4. Gray wolves in central Idaho and the greater Yellowstone Park area have been quite successful. Recovery has been more challenging in the northwest Montana recovery area. In 2003 the Northwest Montana population of the gray wolf was reclassified from endangered to threatened. However, the decision was reversed in 2005 following a court challenge.

As of February 2006 the gray wolf is listed under the Endangered Species Act as endangered throughout the lower forty-eight states, except in Minnesota and where it is an experimental population. Gray wolves in the greater Yellowstone Park area, central Idaho, and portions of Arizona, New Mexico, and Texas are classified as nonessential experimental populations. Gray wolves in Minnesota are designated as threatened.

The red wolf (see Figure 8.5) was once found throughout the eastern United States, but declined as a result of habitat loss and aggressive hunting by humans. The species was first listed as endangered in 1967. The red wolf is a smaller species than its relative, the gray wolf, and, despite its name, may have any of several coat colors including black, brown, gray, and yellow. In 1975, to prevent the immediate extinction of this species, the U.S. Fish and Wildlife Service captured the twenty-some remaining individuals and began a captive breeding program. The red wolf reintroduction program began in 1987, marking the first reintroduction of a species extinct in the wild.

Red wolves now inhabit an area covering about one million acres in North Carolina and Tennessee, including three national wildlife refuges, a Department of Defense bombing range, some state-owned lands, and private property (with the permission and cooperation of landowners). These wolves are classified as nonessential experimental populations. Throughout the remainder of the lower forty-eight states, the red wolf is still considered endangered.

Deer, Caribou, Pronghorn, and Bighorn Sheep

Deer and caribou are members of the Cervidae family, along with elk and moose. Pronghorn are the last surviving members of the Antilocapridae family and are often confused with antelopes. Bighorn sheep belong to the large Bovidae family, which also contains antelopes, bison, gazelles, and domesticated sheep, cattle, and goats. Although these species are diverse in taxonomy, the wild populations share a common threat—they are popular big-game animals for hunters.

As of February 2006 there were five species of big game listed under the Endangered Species Act, as follows:

• Woodland caribou
• Columbian white-tailed deer
• Key deer
• Sonoran pronghorn
• Bighorn sheep

According to the U.S. Fish and Wildlife Service, approximately $3.8 million was spent under the ESA during fiscal year 2004 to preserve imperiled big-game species. More than half of the funds ($2 million) were devoted to the Key deer, found only in the Florida Keys.

KEY DEER

The Key deer is a small deer weighing only sixty to eighty pounds when fully grown and standing about two feet tall. It is the smallest subspecies of the North American white-tailed deer. Overhunting during the early 1900s drove the Key deer to the brink of extinction. Only two dozen individuals remained by the early 1950s when a federal refuge was established for them. In 1967 the Key deer was classified as endangered under the ESA. By 1990 the population reached 250-300 individuals and continued to grow, reaching nearly 700

by the end of the decade. This number is close to what biologists believe to be the historical population of the animal. However, the future of the Key deer is considered insecure due to continuing threats of loss of habitat, a low reproductive rate, and high mortality caused by vehicle strikes. Biologists fear the entire population could be wiped out by a catastrophic event, such as a hurricane.

Recovery criteria for the Key deer (and dozens of other imperiled species) were laid out in a 1999 document, the South Florida Multi-Species Recovery Plan. In 2004 a comprehensive implementation schedule was published for the plan that prioritizes the recovery tasks and identifies the entities, time frames, and costs associated with accomplishing the tasks.

Felines

Feline is the common term used for a member of the Felidae family. This diverse family includes bobcats, cheetahs, cougars, jaguars, jaguarundis, leopards, lions, lynx, panthers, pumas, tigers, and domesticated cats. All of the wild species are under threat as development has left them with less and less natural habitat in which to live.

As of February 2006 there were seven wild feline species listed as endangered or threatened under the ESA in the United States:

• Jaguar
• Gulf Coast jaguarundi

• Sinaloan jaguarundi
• Canada lynx
• Ocelot
• Florida panther
• Puma

Nearly $6 million was spent under the Endangered Species Act to preserve these species during fiscal year 2004. Most of the money was devoted to the Canada lynx ($3 million) and the Florida panther ($2.5 million).

CANADA LYNX

The Canada lynx is a medium-sized feline; adults average thirty to thirty-five inches in length and weigh about twenty pounds. The animal has tufted ears, a short tail, long legs, and large flat paws that allow it to walk on top of the snow. Canada lynx inhabit cold, moist northern forests dominated by coniferous trees.

In 1982 the U.S. Fish and Wildlife Service designated the Canada lynx as a candidate species for listing. However, no action was taken on listing until 1994, when the agency decided to list the species as threatened. This decision was challenged in court by a group of conservation organizations led by Defenders of Wildlife. This began a protracted legal battle that resulted in a 2004 court order forcing the FWS to set critical habitat for the Canada lynx. In November 2005 approximately 18,000 square miles of critical habitat was proposed for the animal by the FWS as follows:

• Maine—approximately 10,633 square miles in portions of Aroostook, Franklin, Penobscot, Piscataquis, and Somerset counties
• Minnesota—approximately 3,546 square miles in portions of Cook, Koochiching, Lake, and St. Louis counties
• Montana and Idaho—approximately 3,549 square miles in portions of Boundary County, Idaho; and Flathead, Glacier, Granite, Lake, Lewis and Clark, Lincoln, Missoula, Pondera, Powell, and Teton counties in Montana
• Washington—approximately 303 square miles in portions of Chelan and Okanogan counties

Also in 2005 the agency developed a preliminary outline for a recovery plan for the Canada lynx including a map of possible recovery areas. (See Figure 8.6.) As of February 2006 the Canada lynx is designated as threatened in fourteen northern states (Colorado, Idaho, Maine, Michigan, Minnesota, Montana, New Hampshire, New York, Oregon, Utah, Vermont, Washington, Wisconsin, and Wyoming).

The Fish and Wildlife Service must make a final determination on critical habitat areas before the end of 2006.

MOUNTAIN LIONS

Mountain lions are large felines that can weigh between seventy and 170 pounds. The twenty-seven subspecies of mountain lion were once found from southern Argentina to northern British Columbia, making them one of the most widely distributed terrestrial species in the Americas. Mountain lions are regionally known as panthers, pumas, or cougars. They prey on large game animals, particularly deer, and wild hogs, rabbits, and rodents. They require large home ranges for securing food—a single individual may have a home range spanning eighty-five square kilometers (about thirty-three square miles). By 1900 mountain lions were nearly extinct due to habitat loss and hunting. Until the 1960s many states offered monetary rewards for the killing of mountain lions. Mountain lions are now found primarily in mountainous, unpopulated areas.

Conservation efforts have met with success in some portions of the country. In fact, there are now so many encounters between humans and mountain lions in California that hikers and park officials are taught how to react to these large cats. Scientists attribute the increased encounter rate to more wilderness ventures by humans as well as a larger mountain lion population—an estimated 6,000 individuals. Because of these events, some people are demanding that hunting be reinstituted.

In California, following a ban on mountain lion hunting, reports of mountain lions rose through the 1990s. In January 2004 a mountain lion killed one bicyclist and severely injured a second in Southern California. The mountain lion was later found and shot. Since 1890 California has reported a total of fourteen mountain lion attacks, of which six were fatal; however, twelve of the attacks occurred between 1986 and 2004.

In most of the eastern United States, however, mountain lions have long been presumed extinct. If they are present, they are still extremely rare. In 1997 several sightings were reported in the Appalachian Mountains, but these have not been confirmed.

The Florida panther is a subspecies of mountain lion that has been considered endangered since 1967. The species has declined due to loss of habitat to urbanization and development, water contamination, and highway traffic. Its population became so small that many individuals began suffering from genetic disorders due to inbreeding. In 1994 and 1995 scientists and wildlife managers introduced Texas cougars, the Florida panthers' closest relatives, into habitats in Florida. Eight female Texas cougars were released. Biologists hoped that interbreeding would strengthen and diversify the Florida panther gene pool. In fact, Florida panthers and Texas cougars once formed a single, interbreeding population that ranged freely throughout the southeastern United States. They were eventually isolated from each other by human encroachment a little more than a hundred years ago.

In December 2005 the Florida Fish and Wildlife Conservation Commission (FFWCC) released Florida Panther Annual Report: 2004–2005 with details on species protection measures (http://www.panther.state.fl.us/news/pdf/FWC2004–2005PantherAnnualReport.pdf). According to the report, there were only thirty to fifty adult Florida panthers in existence as of the late 1980s. The small population size and geographic range combined to limit genetic exchange, resulting in declining health among the species. Five of the Texas cougars released into Florida during the mid-1990s produced at least twenty offspring that began interbreeding with Florida panthers. FFWCC biologists have been tracking subsequent generations of Texas-Florida crossbreeds as part of a genetic restoration project. The scientists hope to develop a long-term management plan that will ensure the survival of the Florida panther as a species. The report estimates that approximately ninety adult individuals make up the Florida panther population.

Other efforts are also underway to help maintain the existing Florida panther gene pool. A captive breeding program was initiated in 1991 with ten panther cubs that had been removed from the wild. It is hoped that captive breeding will allow for the establishment of additional populations in the wild. Scientists are also hopeful that the habitat destruction that threatens the Florida panther has slowed. The primary issue in panther conservation today is providing large enough expanses of protected habitat for the species. This is particularly challenging not simply because the carnivores need large home ranges to feed, but because male panthers are territorial and will not tolerate the presence of other males. About half the area occupied by Florida panthers is private land, including farms, ranches, and citrus groves adjacent to protected reserves. Efforts are being made to secure the cooperation of landowners in conservation efforts.

As a result of the Florida panther's plight and public affection for the animal, in 1982 Florida declared the panther its state animal. Florida businessman Wayne Huizenga named his National Hockey League (NHL) team the Florida Panthers and has pledged many thousands of dollars to panther recovery efforts.

Ferrets

The ferret is a member of the Mustelidae family along with muskrats, badgers, otters, mink, skunks, and weasels. Ferrets are small, furry creatures with long, skinny bodies typically less than two feet long. They have short legs and elongated necks with small heads. Ferrets are carnivores; in the wild they feed on rodents, rabbits, and some reptiles and insects.

As of February 2006 there was one U.S. species of ferret listed under the Endangered Species Act: the black-footed ferret, which is listed as endangered, except in nonessential experimental populations in portions of Arizona, Colorado, Montana, South Dakota, Utah, and Wyoming.

THE BLACK-FOOTED FERRET

The black-footed ferret (see Figure 8.7) is a small, furrow-digging mammal. It is a nocturnal creature and helps to control populations of snakes and rodents, including its primary prey, black-tailed prairie dogs. Black-footed ferrets once ranged over eleven Rocky Mountain states as well as parts of Canada. They have declined drastically because of the large-scale conversion of prairie habitats to farmland, and because their main prey, prairie dogs, have been nearly exterminated by humans. Prairie dogs are considered pests because they dig holes and tunnels just beneath the ground surface. These can cause serious injury to horses or other large animals that step into them. (Some municipalities also poison prairie dogs in city parks, where burrow holes can trip and injure humans.) Poisons used to kill prairie dogs may also kill some ferrets.

Black-footed ferret populations had declined so greatly that the species was put on the Endangered Species List in 1973. However, prairie dog poisonings continued, and by 1979 it was believed that the black-footed ferret was extinct. In 1981 a ferret was sighted in Wyoming and discovered to be part of a remnant population. Rewards were offered for more sightings, and by the end of the year a few black-footed ferret populations had been located. These typically existed in close proximity to prairie dog populations in areas characterized by heavy sagebrush. In 1985 ferret populations were struck by disease, and by 1987, only eighteen black-footed ferrets were in existence. These individuals were captured and entered into a captive breeding program.

The captive breeding of ferrets has been reasonably successful. There are now core populations of several hundred breeding-age individuals in zoos in the United States and Canada and in one facility operated by the U.S. Fish and Wildlife Service. The agency has also tried to reintroduce black-footed ferrets in several states. Studies suggest that each population requires approximately 10,000 acres of black-tailed prairie dog habitat to survive. Unfortunately, prairie dogs are also in decline due to habitat loss and episodes of sylvatic plague, which have decimated many populations. Although some reintroductions have failed, two are doing well—one in national forest habitat in Conata Basin/Badlands, South Dakota, and another in the Charles M. Russell National Wildlife Refuge in Montana. By 2000 there were already many more wild-born than captive-born ferrets at those sites.

The recovery plan for black-footed ferrets was published in 1988. At that time it was hoped the species could be moved from endangered to threatened status by 2010. This would require that 1,500 breeding adults exist in the wild in a minimum of ten separate locations, with a minimum of thirty breeding adults included in each population. Captive breeding and reintroductions of black-footed ferrets were organized by the Black-Footed Ferret Recovery Implementation Team, and involved twenty-six separate state and federal organizations, conservation groups, and Native American tribes.

Rabbits

Rabbits are members of the Leporidae family, along with hares. Rabbits are generally smaller than hares and have somewhat shorter ears. Both species have tall, slender ears and short bodies with long limbs and thick, soft fur. Domesticated rabbits are all descended from European species.

As of February 2006 there were three rabbit species listed as endangered under the ESA in the United States. The species and their primary locations are as follows:

• Lower Keys marsh rabbit—Florida
• Pygmy rabbit—Western states
• Riparian brush rabbit—California

Approximately $1 million was spent under the Endangered Species Act to preserve imperiled rabbit species during fiscal year 2004. Just over half of the money was devoted to the pygmy rabbit, specifically, a distinct population segment (DPS) inhabiting the Columbia River Basin in the state of Washington.

PYGMY RABBIT

The pygmy rabbit is the smallest species in the Leporidae family. Adults weigh up to one pound and can be up to a foot in length. The animals have relatively short rounded ears and small tails. Their only habitat is underneath sagebrush, a rough scrubby bush found in dry alkaline soils in the western United States. Sagebrush provides shelter and the majority of their food source, particularly during the winter. Pygmy rabbits are burrowers and prefer deep loose soils.

Historically the pygmy rabbit was found throughout the semiarid regions of California, Idaho, Montana, Nevada, Utah, Washington, and Wyoming. There is a distinct population segment (DPS) located in the Columbia River basin, an area extending from northern Oregon through eastern Washington. This DPS is considered to be distinct from other populations within the historic range. The pygmy rabbits in the DPS became a candidate species in 1991. A decade later the U.S. Fish and Wildlife Service was forced to issue an emergency endangered listing for the DPS to settle litigation filed by a number of conservation groups. In 2003 a final listing of endangered was made for the Columbia Basin DPS of the pygmy rabbit. At that time the FWS reported that fewer than thirty individuals made up the DPS.

Since 2001 the Washington Department of Fish and Wildlife and the Oregon Zoo have operated a captive propagation project for the endangered pygmy rabbits. It is hoped that the captive animals can be returned to their native habitat at some point in the future.

Rodents

Rodents are members of the order Rodentia, the single largest group of mammals. This order includes mice, rats, beavers, chipmunks, squirrels, prairie dogs, voles, and many other species. There are approximately 1,500 rodent species. Rodents are characterized by their distinctive teeth, particularly a pair of chisel-shaped incisors in each jaw. Although most rodents are plant-eaters, some species include insects in their diets.

As of February 2006 there were twenty-eight rodent species listed under the ESA as endangered or threatened. They are broken down by animal as follows:

• Kangaroo rat—six species
• Mountain beaver—one species
• Mouse—ten species
• Prairie dog—one species
• Rat—three species
• Squirrel—four species
• Vole—three species

Just over $5.4 million was spent under the ESA to conserve imperiled rodents in the United States during fiscal year 2004. The highest expenditures were for the Utah prairie dog ($1 million) and the Alabama beach mouse and Preble's meadow jumping mouse ($0.6 million each).

UTAH PRAIRIE DOG

Prairie dogs are members of the Scieuridae family, along with chipmunks and squirrels. (See Figure 8.8.) They are endemic to the United States and inhabit mostly arid grasslands. They are found from Montana and North Dakota south to Texas. The nineteenth-century explorers Meriwether Lewis and William Clark allegedly named the animals prairie dogs because of their bark-like calls.

Before settlers moved into the West, it is believed that millions of prairie dogs inhabited the area. Prairie dogs are burrowing creatures and live in colonies. They produce holes, tunnels, and dirt mounds that can be very damaging to land used for agriculture. The holes also pose a tripping hazard to horses. As a result, ranchers of the late 1800s and early 1900s tried to eradicate the prairie dog using poison on a large scale. They were assisted in their efforts by the federal government.

The Utah prairie dog is a small furry creature that reaches twelve to fourteen inches in length when full grown. They are reddish brown in color and have short, white-tipped tails. Prior to the control programs of the 1920s, approximately 100,000 of the animals lived in Utah. By 1972 the population had been reduced to about 3,000 individuals. Massive poisoning by humans, disease (a form of plague), and loss of suitable habitat are blamed for the population decline. In 1973 the FWS listed the Utah prairie dog as endangered under the ESA. Over the next decade, conservation efforts began to pay off. More than 3,500 of the animals were counted during a 1982 census. However, angry farmers began reporting massive crop damage caused by the creatures, particularly to summer alfalfa crops, a favorite food source for the prairie dogs. The state of Utah petitioned the U.S. Fish and Wildlife Service to downlist the species from endangered to threatened; this reclassification took place in 1984.

The FWS recognized that Utah farmers were not going to tolerate continuing threats to their crops from the prairie dogs. In a unique action the agency established a special regulation allowing the Utah Division of Wildlife Resources to issue permits to private landowners that wished to kill Utah prairie dogs on their property. A maximum of 5,000 of the "nuisance" animals could be "taken" annually in specific portions of the state. In 1991 the maximum allowable take was raised to 6,000 animals per year, and the area of allowed take was expanded to include all private lands within the species' range. In addition, the FWS began relocating Utah prairie dogs from private lands to lands under control of the federal government. In 2004 the Utah Division of Wildlife Resources estimated the species population at around 8,000 individuals. They are found only in limited areas of the state as shown in Figure 8.9.

In November 2005 the U.S. Fish and Wildlife Service assessed a $10,000 civil penalty against a Utah developer accused of killing Utah prairie dogs without a permit during construction of a residential development in Enoch, Utah, in 1995 (http://mountain-prairie.fws.gov/PRESSREL/05-84.htm). A $15,000 penalty had been originally assessed against the developer, but this amount was reduced to $10,000 following a lengthy court battle.

Shrews

Shrews are members of the order Insectivora, along with moles and hedgehogs. Shrews are small furry creatures with long, pointed snouts.

As of February 2006 there was one shrew species listed as endangered under the ESA—the ornate Buena Vista Lake shrew, which is endemic to California. Less than $200,000 was spent under the ESA on this animal during fiscal year 2004.

The Buena Vista Lake shrew is one of nine subspecies of the ornate shrew. Adult animals reach only about four inches in length and weigh around a quarter of an ounce. Historically the subspecies was found throughout freshwater wetlands near Buena Vista Lake in south-central California. Much of this area has been converted to agricultural purposes, and many of the wetlands have been drained or filled. As a result, populations of the subspecies are believed to be severely depleted.

In 1996 the Buena Vista Lake shrew was designated a candidate species by the U.S. Fish and Wildlife Service. In 2002 the agency was forced under court order to make a listing determination for the animal; it was listed as endangered. Following additional litigation the FWS was ordered to make a final critical habitat determination by 2005. In January 2005 the agency designated eighty-four acres in Kern County, California, as critical habitat for the Buena Vista Lake shrew.

IMPERILED TERRESTRIAL MAMMALS AROUND THE WORLD

As of March 2006 the FWS listed 257 foreign species of terrestrial mammals as endangered or threatened under the Endangered Species Act. (See Table 8.3.) Many of the species are from groups also imperiled in the United States, such as bats, bears, big game, canines, felines, rabbits, and rodents. In addition, there are exotic animals not native to this country, particularly elephants, pandas, primates, and rhinoceroses.

The 2004 IUCN Red List of Threatened Species of the World Conservation Union listed 1,101 mammals as critically endangered, endangered, or vulnerable. Approximately 960 of these mammals could be considered terrestrial mammals. Orders with large numbers of listed animals are as follows:

• Rodentia (rodents)—315 species
• Chiroptera (bats)—247 species
• Insectivora (moles, shrews & hedgehogs)—124 species
• Primates—114 species
• Artiodactyla (big game, camels, hippos, etc.)—72 species
• Carnivora (bears, big cats, etc.)—56 species

Together, these orders comprise nearly 90% of the terrestrial mammals on the 2004 IUCN Red List. Among the remaining listed species are some animals that garner high levels of public interest—elephants, koalas, and rhinoceroses.

The habitat types occupied by the largest numbers of threatened mammal species are lowland and tropical rainforests, both of which are being rapidly degraded.

Bears

Bear species are imperiled worldwide. They are killed in large numbers by poachers, who sell bear organs and body parts in the illegal wildlife trade. These organs usually end up in Asia, where they are valued as ingredients in treatments for ailments or illnesses, or to delay the effects of aging—although there is no evidence that such treatments are effective. In North America bears are threatened by loss of habitat and are eliminated for posing a danger to humans and livestock. In 2000 biathlete Mary Beth Miller was mauled to death by a black bear as she ran along a wooded path during her training routine in Quebec, Canada. The tragedy ignited controversy over attempts by Canadian officials to protect the species, including the cancellation of an annual bear hunt.

Big Cats

Wild tigers are found exclusively in Asia, from India to Siberia. Although the world tiger population surpassed 100,000 in the nineteenth century, experts fear that fewer than 10,000 remained in the early 2000s. In addition to habitat loss, countless tigers fall victim to the illegal wildlife trade every year. Many tiger body parts are used as ingredients in traditional Chinese medicine, and the big cats are also prized in the exotic pet industry.

In 1999 the Wildlife Conservation Society reported a rebound in the world tiger population, in part because of a worldwide moratorium on tiger hunting imposed by listing in the Convention on International Trade in Endangered Species (CITES) treaty. However, ecologists warn that tigers, which hunt deer, wild pigs, cattle, antelope, and other large mammals, are threatened seriously by loss of prey, much of which consists of nonprotected species being eliminated by hunters.

THE SIBERIAN TIGER

The Siberian tiger (see Figure 8.10) is the largest cat in the world and one of the world's most endangered species, with only 500 individuals estimated to exist in the wild. There are also several hundred Siberian tigers in captivity. The Siberian tiger, also known as the Amur tiger, once occupied mixed deciduous and coniferous forest habitats in the Amur-Ussuri area in Siberia, as well as in northern China and Korea. It is now believed to be extinct, or nearly extinct, in China and Korea. Individuals reach lengths of eight to ten feet and weigh up to 800 pounds. They eat wild boars, Sika deer, and elk. Siberian tigers are territorial and require large home ranges of some 500 to 600 square miles.

Populations have suffered greatly from habitat loss caused by logging and deforestation, as well as illegal trade. The Siberian tiger is sought for its skin, bones,

eyes, whiskers, teeth, internal organs, and genitals. These are used for everything from skin cures to tooth medicine. In Russia, where unemployment is high, poachers have flooded nearby Asian markets with tiger parts. The financially strapped Russian government can devote neither money nor time to protecting the tigers. Like the Florida panther, the Siberian tiger has also been weakened by inbreeding, which increases the possibility of reproductive problems and birth defects.

CHEETAHS

The cheetah is the fastest land animal on Earth, able to sprint at speeds up to seventy miles per hour. Cheetahs occupy grassland, shrubland, and woodland habitats. Their range once extended through most of Africa as well as southwestern Asia. Currently, cheetahs are found only in a few areas in Iran, North Africa, and sub-Saharan Africa. Cheetahs hunt small prey, particularly Thomson's gazelle. The cheetah has been listed in CITES Appendix I since 1975. In 2006 there were an estimated 12,500 cheetahs in the wild, according to the Cheetah Conservation Fund (http://www.cheetah.org/), a dramatic decrease from approximately 100,000 at the beginning of the twentieth century.

Cheetah populations have declined for many reasons. Much of the species' habitat has been developed for agricultural or ranching use, and many of the cats are shot by farmers who wish to protect their livestock. In addition, because of their declining numbers and loss of habitat, cheetahs are badly inbred, and many individuals are infertile. Cheetahs are also smaller and less aggressive than other predators that share their environment (including lions and leopards) and often have their food kills stolen or their cubs killed. Conservation biologists have determined that in order to save the cheetah, human assistance in the form of habitat protection, protection from competitor species, and measures to improve the genetic diversity of the species are required.

Elephants

Elephants are the largest land animals on Earth. They are frequently described as the "architects" of the savanna habitats in which they live. Elephants dig water holes, keep forest growth in check, and open up grasslands that support other species, including the livestock of African herders. Elephants are highly intelligent, emotional animals and form socially complex herds. There are two species of elephants, African elephants and Asian elephants, both of which are highly endangered. The African elephant (see Figure 8.11), which sometimes weighs as much as six tons, is the larger species. According to the World Wildlife Fund in "Elephant Ivory Trade," an estimated 500,000 African elephants and between 35,000 and 50,000 Asian elephants remain in the wild as of 2006.

Elephants have huge protruding teeth—tusks—made of ivory. Ivory is valued by humans for several reasons, particularly for use in making jewelry and figurines. Piano keys were also once made almost exclusively of ivory; however, that practice has ceased. The market for ivory has had tragic consequences for African elephants. Their numbers dropped from over ten million individuals in 1900 to only 600,000 in 1989. As a result of this decline, the UN-administered CITES banned worldwide commerce in ivory and other elephant products in 1990. However, like rhinoceros horns, elephant tusks continue to be illegally traded. Numerous elephants are poached each year. Esmond Martin and Tom Milliken in No Oasis: The Egyptian Ivory Trade in 2005 (June 2005, http://www.traffic.org/news/press-releases/TRAFFIC_%20Egypt.pdf) report the price of poached elephant ivory as high as $150 per pound in 2005. The price has risen substantially in recent years, indicating poachers are facing pressure from increased law enforcement.

Despite continued poaching, elephant populations have recovered somewhat since receiving CITES protection. In 1997 Zimbabwe requested that CITES change the listing status of the African elephant in three South African nations—Zimbabwe, Botswana, and Namibia—from Appendix I status (a species in immediate danger of extinction) to Appendix II status (threatened in the absence of trade controls), and include a yearly quota for ivory trade. South Africa has requested a similar downlisting. Kenya, India, and other nations, along with many environmental organizations, opposed the downlisting, in part because they maintained that a reopening of the ivory trade might cause a resurgence in demand and poaching. CITES responded by downlisting the elephant to Appendix II, while simultaneously initiating a program, the Monitoring of Illegal Killing of Elephants (MIKE; 1999, http://www.cites.org/eng/prog/MIKE/index.shtml) to better assess poaching. CITES also allowed a one-time sale of stockpiled ivory from Namibia, Botswana, and Zimbabwe to Japan. This one-time ivory transaction was made in 1999 and grossed approximately $5 million.

At subsequent CITES Conferences, debate continued about authorizing ivory sales and relisting the elephant under CITES Appendix I as immediately endangered. In the end, the opposing factions reached a compromise in which elephants remained listed under Appendix II, and the ban on most ivory sales remained in effect. At the 2002 CITES Conference, CITES conditionally accepted one-time sales by Botswana, Namibia, and South Africa of ivory collected from elephants that died a natural death. However, the sales can occur only after data is collected on poaching and population levels.

In June 2005 TRAFFIC (an organization that monitors worldwide wildlife trade) and the World Wildlife Fund (WWF) issued a joint statement to CITES on the status of ivory trade. The statement notes that illegal ivory sales in Africa and Asia continue to be a problem in several countries, notably Egypt, Mozambique, Angola, and Thailand. However, Ethiopia was reported to have made great progress in reducing ivory trade. In January 2005 Ethiopian officials conducted a major sweep of retail outlets and seized large quantities of ivory products. A few months later undercover TRAFFIC investigators visited the same area and found few ivory products for sale.

Although the ivory trade has always been the largest threat to elephants, conflicts between humans and elephants are an increasing issue. The ranges of many elephant herds now extend outside protected refuges, and elephants frequently come into contact with farmers, eating or otherwise destroying crops. Increasing human settlement in areas inhabited by elephants will likely result in more conflicts over time.

Pandas

Few creatures have engendered more human affection than the giant panda, with its roly-poly character, small ears, and black eye patches on a snow-white face. Giant pandas are highly endangered. According to the National Zoo, there are approximately 1,600 pandas in the wild and about 160 individuals in captivity as of 2006. Pandas are endemic to portions of southwestern China, where they inhabit a few fragmentary areas of high-altitude bamboo forest. Unlike other bear species, to which they are closely related, pandas have a vegetarian diet that consists entirely of bamboo. Pandas also have a sixth digit which functions like a thumb, and which they use to peel tender bamboo leaves from their stalks.

Pandas have become star attractions at many zoos, where they draw scores of visitors. Despite tremendous efforts, pandas have proven notoriously difficult to breed in captivity. The birth of a giant panda cub, named Hua Mei, at the San Diego Zoo in 1999 was a major event, with millions of people following the cub's progress online and in the papers through her first days of life. Hua Mei was the first panda born in captivity outside of China.

The San Diego Zoo pays China $1 million annually for the loan of adult pandas. These funds are used to support panda conservation efforts in China, including the purchase of land for refuges as well as the development of habitat corridors to link protected areas. The agreement also requires that pandas born at the San Diego Zoo will be returned to China after they are three years old. Hua Mei was flown to China in February 2004 to join nearly seventy pandas at the Wolong Giant Panda Protection Research Centre in the Sichuan Province of China. In August 2005 she gave birth to twin cubs after being artificially inseminated.

As of March 2006 zoos in Washington, D.C., Memphis, Tennessee, and Atlanta, Georgia, also have giant pandas on loan from China. In 2000 the National Zoo in Washington, D.C., agreed to pay China $10 million over a ten-year period in exchange for the loan of giant pandas. In July 2005 a male cub was born at the National Zoo. Following a naming contest, the cub was named Tai Shan, which means "peaceful mountain." In August 2005 a female cub was born at the San Diego Zoo, the third cub born there. She was later named Su Lin, which translates to English as "a little bit of something very cute." Su Lin's older brother Mei Sheng was born in August 2003. His name means both "born in the USA" and "beautiful life."

In March 2006 officials from the U.S. zoos keeping giant pandas traveled to China to begin negotiations on new loan contracts for the animals. The zoos hope to reduce the high loan costs they are charged for Chinese pandas. They also hope to be excused from contract stipulations that require the return to China of cubs that reach three years old. U.S. zoo officials believe that the Chinese will be amenable to these new terms because the Chinese breeding program for giant pandas has been so successful.

RED PANDAS

The red panda is also called the lesser panda because it is significantly smaller than the giant panda, with a length of about forty-two inches and a weight of only seven to fourteen pounds. Red pandas are not related to bears—they are actually raccoon relatives. Red pandas are virtually extinct in the wild, mostly because of habitat loss and degradation. Red pandas occupy temperate forests in the foothills of the Himalayas in Nepal, Burma, and southwestern China at altitudes between 5,000 and 13,000 feet. They are solitary creatures, occupying non-overlapping home ranges of approximately one square mile for females and two square miles for males. Like giant pandas, red pandas eat bamboo, focusing on the tenderest leaves. Because bamboo is not very nutritious, red pandas spend as much as thirteen hours each day eating in order to acquire the nutrients they need. Red pandas have difficulty recovering from population declines because of a slow rate of reproduction. A captive breeding effort for red pandas is underway at zoos across the world to prevent the complete extinction of this species.

Big Game

Most big-game species are members of the Artiodactyla order. This order contains a variety of ungulates (hoofed animals), including antelopes, bison, buffalo, camels, deer, goats, hartebeests, hippos, gazelles, impalas, and sheep. Many of the wild species have been over-hunted for their meat, bones, or horns. Horns are used in traditional Chinese medicine and are popular trophies for big-game hunters. The argali is the largest of the wild sheep and is highly prized for its large curved horns. (See Figure 8.12.)

Big-game species also face threats from domesticated livestock due to competition for habitat and food resources.

Primates

The World Conservation Union (IUCN), in its 2004 IUCN Red List of Threatened Species, reported that the 296 examined species of primates (excluding humans) are among the most endangered mammals. Since the 1996 IUCN assessment, the number of "critically endangered" primates increased from thirteen to twenty species, and the number of "endangered" primates rose from twenty-nine to forty-eight. Another forty-six primates are considered "vulnerable." Critically endangered primate species included the Roloway monkey (lowland tropical rainforest in Ghana and Cote d'Ivoire), Mentawai macaque (Indonesia), Sclater's black lemur (lowland tropical rainforest, Madagascar), red-handed howling monkey (Brazil), and the black lion tamarin (lowland tropical rainforest, Brazil), among others. Much of the increased endangerment of primate species is due to loss of habitat and hunting.

Countries with large numbers of primate species include Brazil, Indonesia, Democratic Republic of Congo, and Madagascar. Many of the most endangered primate species are found on Madagascar, which has a diverse and unique primate fauna. The majority of Madagascar's primate species are endemic—that is, they are found nowhere else on earth.

Primates are highly threatened partly because they are dependent on large expanses of tropical forests, a habitat under siege worldwide. In regions where tropical forest degradation and conversion have been most intense, such as South and Southeast Asia, Madagascar, and Brazil, as many as 70% of native primate species face extinction.

Habitat loss, especially the fragmentation and conversion of tropical forests for road building and agriculture, contributes to the decline of nearly 90% of all IUCN-listed primates. In Indonesia and Borneo, for example, home to most of the world's 50,000 to 60,000 orangutans (see Figure 8.13), deforestation has shrunk orangutan habitat by over 90%. Logging and extensive burning have caused many orangutans to flee the forests for villages, where they have been killed or captured by humans.

Some threatened primates also face pressures from excessive hunting and poaching. Today, almost all countries have either banned or strictly regulated the trade of primates, but these laws are often hard to enforce. Primates are also used in medical research because of their close biological relationship with humans.

Not all relationships between primates and humans are exploitative. People in some regions protect primates from harm by according them sacred status or by making it taboo to hunt or eat them. One of the rarest African monkeys, the Sclater's guenon, survives in three areas of Nigeria in part because residents regard the animal as sacred.

Good news arrived in January 2004 when it was announced that a census led by the International Gorilla Conservation Program found that the highly endangered mountain gorilla had experienced a population rebound, with numbers increasing 17% between 1989 and 2003 in the Virunga forest of Rwanda, Uganda, and the Democratic Republic of Congo. Gorilla populations had plummeted in the 1960s and 1970s due to civil unrest, habitat destruction, and poaching. A total of 380 mountain gorillas were counted in the Virunga forest and an additional 320 were identified in the Bwindi Impenetrable Forest National Park in Uganda, bringing the world total to 700, according to the African Wildlife Foundation (http://www.awf.org/gorillaupdate/).

Rhinoceros

Rhinoceros are among the largest land mammals. They weigh up to 8,000 pounds—as much as fifty average-sized men—and are herbivorous grazers. The name rhinoceros is made up of two Greek words meaning "nose" and "horn," and rhinos are in fact the only animals on Earth that have horns on their noses. Figure 8.14 shows an African white rhinoceros with two horns. The female may be identified by her longer, more slender primary horn.

Rhinoceros have roamed the land for more than forty million years, but in less than a century, humans—their only predators—have reduced populations to dangerously low levels. There are five species of rhinoceros—the black rhino (African), white rhino (African), Sumatran rhino (found in Borneo, Malaysia, and Sumatra), Javan rhino (found in Indonesia and Vietnam), and Indian rhino (found in both India and Nepal). Certain rhino species can be divided into distinct subspecies. For example, the Javan rhino has two subspecies, one found in Vietnam, the other in Indonesia. According to the International Rhino Foundation (IRF; http://www.rhinos-irf.org/rhinoinformation/javanrhino/subspecies/vietnamese.htm), the Vietnamese subspecies consists of only one tiny population of two to seven individuals, and was thought extinct until this tiny population was discovered in 1999. All rhinos are close to extinction.

Hunting has been the primary cause of rhinoceros decline. Rhinoceros horn is highly prized as an aphrodisiac, as well as an ingredient in Chinese medicine (although its potency has never been shown). Rhinos were first listed by CITES in 1976. This banned international trade in the species and their products. In 1992 CITES also started requiring the destruction of horn caches confiscated from poachers. Nonetheless, people continue to buy and consume rhinoceros horn, and many poachers are willing to risk death to acquire it.

INDIAN RHINOS

Conservation efforts have improved the status of some rhino species. The Indian rhinoceros, which was reduced to fewer than 100 individuals in the mid-1970s, has experienced significant population growth in the past twenty-five years. According to the IRF, in 2006 there were approximately 2,400 Indian rhinos in the wild. Population increase resulted from habitat protection, including the designation of several national parks, as well as measures that curbed poaching.

AFRICAN RHINOS

Africa is home to two species of highly imperiled rhinoceros, the black rhino and the white rhino. Both species have a second, smaller horn situated slightly behind the larger main horn. They are threatened primarily by poaching. Wildlife officials in Zimbabwe, Swaziland, and Namibia have gone so far as to sever rhino horns in an effort to curtail poaching. Most experts, however, discourage the practice, as animals use their horns for both digging and defense. In 2006 the IRF reported 3,610 black rhinos in the wild. Of the black rhinoceros subspecies, the western variety is the most severely endangered, with only ten currently found in the wild. The IRF reported 11,330 white rhinos in 2006. African rhino numbers have risen in recent years, primarily due to improved management as well as private sector and community involvement. Captive breeding efforts for the African rhino species have also met with some success, particularly at the San Diego Wild Animal Park, and may aid in the conservation of these species.