Wild Yellowstone(2020)

In the 1960s, NPS wildlife management policy changed to allow populations to manage themselves. Many suggested at the time that for such regulation to succeed, the wolf had to be a part of the picture.

Wild Yellowstone(2020)

In late 1994 and early 1995, and again in 1996, FWS and Canadian wildlife biologists captured wolves in Canada and relocated and released them in both Yellowstone and central Idaho. In mid-January 1995, 14 wolves were temporarily penned in Yellowstone; the first eight wolves on January 12, and the second six on January 19, 1995. Wolves from one social group were together in each acclimation pen. On January 23, 1996, 11 more wolves were brought to Yellowstone for the second year of wolf restoration. Four days later they were joined by another six wolves. The wolves ranged from 72 to 130 pounds and from approximately nine months to five years in age. They included wolves known to have fed on bison. Groups included breeding adults and younger wolves one to two years old.

Wolves are now managed by the appropriate state, tribal, or federal agencies; management in national parks and national wildlife refuges continues to be guided by existing authorizing and management legislation and regulations.

• Kingdom: Animalia

• Phylum: Chordata

• Class: Mammalia

• Order: Carnivora

• Family: Canidae (dog family)

• Genus: Canis (Latin word meaning "dog")

• Species: lupus (Greek word meaning "wolf")

• Common names: gray wolf, timber wolf

• Names in other languages: Lobo (Spanish), Loup (French), Lupo (Italian), Varg (Swedish), Ulv (Norwegian)

• Physical CharacteristicsAverage body mass: males 110 pounds (50 kg); females 90 pounds (41 kg)

• Heaviest known wolf in Yellowstone: 148 pounds (wolf 760M of Yellowstone Delta pack with no food in stomach)

• Average height at shoulder: males 81 cm, females 77 cm

• Average length: 181 cm

• Eyes: blue at birth, light yellow to gold to brown as an adult

• Number of bones: 319 males, 318 females

• Number of teeth: 42

• Dental formulae: incisors 3 top/3 bottom, canines 1/1, premolars 4/4, molars 3/2 (on each side)

• Pelage: gray or black (ratio 50:50), rarely white

• Black coat color: caused by K-locus gene thought to have originated from historic hybridization with domestic dogs 500-14,000 years ago

• Locomotion: tetrapedal, digitigrade

• Average rate of speed: 5 miles/hour (8 kph)

• Top speed: 35 miles/hour (56 kph)

• Body temperature: 100-102.5 F (37.3-39.1 C)

• Respiration: 10-30 breathes per minute

• Heart rate: 70-120 beats per minute

• Bite pressure: 1,200 psi

• Senses and CommunicationSmell: excellent, although unmeasured. Estimated to be thousands of times better than humans

• Vision: excellent night vision; no red or green cones, but have blue and yellow cones

• Hearing: little is known, but probably similar to dogs (relatively normal hearing abilities compared to other mammals)

• Howling function: many uses, including intrapack communication, advertising territory, coordinating social activities

• Distance howling can be heard: forest=11km (6.6 mi), open areas=16 km (9.6 mi)

• DietFeeding habits: generalist carnivore; scavenges when possible and has been known to eat small amounts of vegetation

• Primary food sources in Yellowstone: Winter: elk (>96%), bison (3-4% and increasing in recent years; deer (1.5%); Spring: elk (89%), bison (7%), deer (7.1%); Summer: elk (85%), bison (14.1%), deer (5 years old: 18%

• Current North American population: 67,100-74,100 (53,600-57,600 of these in Canada)

• Average home range size in Yellowstone (northern range): 274 km2 (range=58-1,151 km2)

• Average home range size in Yellowstone (interior): 620 km2 (range=105-1675 km2)

• Average home range size in Yellowstone (park-wide): 428 km2

• Group of wolves: pack/ family (one of few eusocial species)

• Average pack size in Yellowstone: 9.8

• Largest pack recorded in Yellowstone: Druid Peak, 37 wolves (2001); may be the largest ever recorded (42 wolves seen together in Wood Buffalo National Park (1974) but unknown if they were a single pack)

• Percent of population that are lone wolves in Yellowstone: 2-5%

• Percent of population that are lone wolves in North America: 10-15%

• Sex ratio: 50:50

• Breeding and PupsMating: usually monogamous, but about 25% of packs have multiple breeding pairs under polygymous matings

• Courtship: mid-February

• Gestation: 63 days

• Birth period: mid-April

• Birth location: den

• Typical dens: excavated under large roots, boulders, hillsides, caves with a tunnel leading to an enlarged chamber; several entrances and chambers may be present

• Den emergence: 10-14 days

• Average litter size in Yellowstone: 4.4 at den emergence, 3.2 survive until late December

• Maximum litter size recorded in Yellowstone: 11

• Split litters: multiple fathers per litter have not been detected in wild gray wolves

• Weaning: 5-9 weeks from milk, then brought food (regurgitation) for another 3 months

• Milk content: 6.6% fat; 144 kCal per 100 grams

• Rendezvous sites: used as wolf pups get older as a central homesite; time spent there and number of homesites varies widely between packs

• Average female age at first litter in Yellowstone: 2.7

• Oonset of female reproduction senescence: 4-5 years

• Interbirth interval: can be every year

• Eyes open: 12-14 days

• Dispersal: both sexes, YNP average age 2 years, 1 month; range 1-4 years

Are bison an endangered species?Bison are not listed as a threatened or endangered species. Approximately 30,000 bison live in public and private herds in North America; they are managed for conservation goals. Approximately 400,000 bison are raised as livestock however, wild bison are rare. Yellowstone bison represent the best example for preservation of wild plains bison in North America.

As attitudes towards wild ecosystems changed, people began questioning whether a wolf-less Yellowstone environment was a healthy one. Once the wolves were gone, the elk population exploded and they grazed their way across the landscape killing young brush and trees. As early as the 1930s, scientists were alarmed by the degradation and were worried about erosion and plants dying off.

In the years that followed, wolves brought the elk population down and protected the open valleys from overgrazing. However, the number of elk killed was double than estimated and many local hunters stirred controversy by protesting that the wolves will end up killing ALL of the elk. Today the debate is still strong. Inside the park, scientists joyously exclaim that the wolves have saved Yellowstone. Cross the park border into a gateway town and you will surely hear how wolves kill for the pleasure of killing and are terrorizing ranches and wildlife.

As winter's grasp approaches, wildlife in the Greater Yellowstone are beginning to migrate to low elevation refuges, avoiding deep snows in the high country. Though many animals like deer, moose, and elk can be found year round in Jackson Hole, bighorn sheep (Ovis canadensis) are most easily viewed during the winter months when they travel from the high peaks of the Gros Ventre Mountains to Miller Butte on the National Elk Refuge. Read on to learn more about this charismatic big game species. Read more

An accredited land trust and 501(c)(3) organization, Vital Ground conserves habitat for grizzly bears and other wildlife in the Northern Rockies. Founded in 1990 and based in Missoula, Mont., the organization also partners with communities to prevent conflicts between bears and people.

Vital Ground works in the northern Rocky Mountains to conserve land for grizzly bears and other wildlife. As a land trust, we focus on private lands that connect larger wild strongholds, building lifelines for grizzlies and all things wild.

Yellowstone Cougars provides objective scientific data at the forefront of understanding cougars and large carnivore community structure and management issues in the Greater Yellowstone Ecosystem, as well as in other areas where wolves and cougars are reestablishing. Intended for an audience of scientists, wildlife managers, conservationists, and academics, the book also sets a theoretical precedent for writing about competition between carnivorous mammals.

Sixty-seven different mammals live in Yellowstone National Park. Some, like the wolverine and Canada Lynx, are rarely seen but enjoy the vast expanse of undisturbed habitat. Elk, mule deer, bison, moose, bighorn sheep, and pronghorn are all abundant, along with cougar, coyote, bear, gray wolf, fox, and river otter (to name but a few.) We've outlined the animals you are most likely to see (keep in mind, these animals indeed are wild, so there are no guarantees!) 041b061a72