The epic history of the Druids, one of more than a dozen packs now occupying the 2.2 million acres of Yellowstone, is documented in NATURE’s In the Valley of the Wolves, was produced and shot in High Definition by Emmy-award winning filmmaker Bob Landis.

On the Web site for In the Valley of the Wolves, you’ll learn how the successful reintroduction of Yellowstone’s apex predator has changed the entire ecosystem of the park, and about the threats that these majestic animals continue to face on their road to recovery.

Watch an online-exclusive video. In this video, Emmy Award-winning wildlife cinematographer Bob Landis discusses the making of the film, including the ideal circumstances for filming a predation scene; the importance of spending a vast amount of time in the field; the uniqueness of Yellowstone’s Druid wolf pack, and more.

To order a copy of In the Valley of the Wolves, visit the NATURE Shop.

Online content for In the Valley of the Wolves was originally posted November 2007.

Gray Wolf (Canis lupus)

• Type: Mammal
• Family: Canidae
• Habitat: Open tundra, forests, prairies
• Location: Some areas of the continental U.S., Alaska, Canada, Mexico, Europe, and Asia
• Diet: Carnivore
• Average lifespan in the wild: 10 – 18 years
• Size: Shoulder height: 26 – 36 inches (.6 – .9 m); overall length, 4′3 – 6′9 (130 – 205 cm)
• Weight: 70 – 130 lb (26 – 59 kg)

Once the world’s most widely distributed land mammal, the gray wolf, or timber wolf, was systematically eradicated from the continental United States in the 20th century and was added to the endangered species list in 1973. Gray wolves are considered a “keystone” species — one with a dramatic effect on its environment. For example, the recent reintroduction of gray wolves to Yellowstone National Park has led to the recovery of the entire ecosystem, from vegetation to beavers to hawks and eagles. The animal is the direct descendent of the ancestor to dogs. Wolves are distinguished from dogs by their long, powerful muzzle, yellow eyes, longer legs, larger paws (which are slightly webbed for walking more easily on snow) and bigger teeth. The wolf has a two-layered coat, which is generally gray, but can vary in color from white to black.

The highly social animal lives in a pack of around five to nine members, led by an alpha pair — generally the only pack members allowed to breed, and mated for life — plus their offspring and a few unrelated wolves. All pack members care for young, and the pack hunts cooperatively, usually at night, to chase down prey such as moose, elk, bison, reindeer, beaver, and rabbit. The wolves slash at the hind leg tendons of their quarry to disable it, or herd it back toward waiting pack members. Wolf howls and other vocalizations allow the pack to communicate, and advertise their territories (which can cover from 100 to 260 square miles) to neighboring packs.

Did you know? The gray wolf can gallop over short distances at speeds of more than 30 miles per hour, but will usually give up the hunt if it doesn’t overtake its victim within the first 1,000 yards.

Related Episodes:

• In the Valley of the Wolves

The original five members of the Druid Peak pack — #38 and #39, the alpha male and female, and female pups #40, #41, and #42 — were captured near Fort St. John in British Columbia and relocated to Yellowstone’s acclimation pens before being released in April 1996 in the Park’s scenic Lamar Valley. The nearly treeless Lamar Valley is often considered Yellowstone’s most prized hunting grounds, and the most visible wolf territory in the Park.

On this public stage, the Druids displayed early signs of the upheaval and drama that would eventually come to characterize the group. During that first year in Yellowstone, a yearling male, #31, dispersed from the nearby Chief Joseph pack and joined the group, while alpha female #39 left the pack completely to become a lone wolf — perhaps driven off by #40, her own ruthless daughter, who began a terrible reign as the pack’s alpha female.

In 1997, pups were born to #41 and #42, the subordinate females, but none to the aggressive alpha female, #40. Lone wolf #39 reunited with the pack briefly, then left once again in November — this time with her daughter, #41 (who also may have been driven off by #40). The pack’s two males, #31 and #38 were shot and killed in December, setting the stage for the dominance of a new male, #21, dispersed from the Rose Creek Pack. By the end of 1998, the Lamar Valley Druids had seven members, and a growing reputation for conflict. The constant harassment of beta female #42 by her sister, #40, earned #42 the nickname “Cinderella” by the Yellowstone researchers. The put-upon Cinderella created a den and gave birth to pups in 1998, but none survived; the following year #40 attacked #42 in her den, and she again produced no offspring.

Casanova

Cinderella finally reached the ball in 2000, after a violent turn of events that put her at the head of the pack. She and the other female members of the pack, perhaps tired of #40’s iron-pawed leadership, turned on the alpha female, and killed her. At least three litters were born to the liberated females; 20 of the 21 survived. The Druids, 27 strong, became the largest pack in Yellowstone. In 2001, another 10 pups were added to the group, and the 37-member Druid pack became perhaps the largest wolf pack ever documented.

Like all dynasties, however, the Druids were destined for a fall. In 2002, the massive pack reached critical mass, and splintered. Three new packs, the Agate Creek, Geode Creek, and Slough Creek packs, were created, each anchored by a former Druid female born at the same den in Lamar Valley in 1997. The Druids were left with 11 members by 2002’s end, including the matriarch, Cinderella, and the long-time alpha male, #21. The pack expanded to 17 members by the end of 2003, aided by the arrival of a lone black male, #302, formerly of the Leopold pack. #302 may have fathered all of the pups not born to the alpha female. To wolf researchers, he was “Casanova” — a lover, not a fighter, who wooed the females in the group while staying appropriately submissive to alpha male, #21.

In 2004, the Druids once again suffered terrible losses; longtime alpha female #42 was killed by members of a rival pack, and the aging patriarch was found dead in the summer. At the same time, however, the neighboring Slough Creek pack began to spend more time on the northwestern boundary of Druid territory. Their incursions into Druid turf culminated in a decisive battle in 2005 that ousted the formerly dominant Druid wolves from the Lamar Valley. Two adult female Druids died that year — one killed by the Sloughs — and no pups survived. The pack was reduced to just four members, and looked to be nearing its end.

In true soap opera fashion, however, the Druids’ epic tale does not conclude with their exile. In 2006, from their new location in an area called Cache Creek, aided by Casanova and #480, the new alpha male, the pack began to rebuild. Both of the pack’s adult females successfully bred, producing eight surviving pups. The Druids pushed back against the Slough Creek pack — which suffered its own losses earlier in the year after a run-in with an unknown pack from the north — and reclaimed their traditional territory in the Soda Butte and Lamar Valleys; six pups were born there in 2007. The Druids, for now, are home.

When the gray wolf was eradicated from Yellowstone National Park in the 1920s, more was lost than just the noble and fascinating predator. The park’s entire ecosystem changed. Now, nearly a dozen years since the wolves returned, the recovery of that system to its natural balance is well underway, say ecologists William Ripple and Robert Beschta of Oregon State University.

The researchers began studying the interaction of wolves with other parts of the ecosystem somewhat indirectly. “Back in 1997, I became aware that the aspen trees in Yellowstone were declining,” Ripple explains. “There was disagreement and confusion as to why these trees were disappearing, so I set out with graduate students to unravel this mystery.”

“We went out to the park and we cored the trees and studied the tree rings which show the annual growth, and we were able to age the trees that are still there,” Ripple says. The tree ring analysis indicated that the aspen, which usually regenerate themselves by sending off new shoots rather than by producing seeds, had stopped producing new trees during the first half of the 20th century.

Ripple and his colleagues looked at several possible variables that could be affecting the trees, from climate fluctuations to a changing natural forest fire regime. But the only factor that fit, Ripple says, was the browsing patterns of elk, which like to feed on the seedlings of aspen trees, and which are also a favored food of gray wolves: “The wolves were killed off from Yellowstone in the 1920s, which correlated with the start of the aspen decline. That led us to develop the hypothesis that the wolves were connected in some way to the aspen trees.” That connection, Ripple concluded, was mediated through elk: “We connected the dots: wolves affect elk; elk affect aspen; and therefore wolves affect aspen.”

Aspen grove (photo: NPS/J Schmidt; 1977)

Ripple and his colleagues subsequently discovered other changes. In some areas, willows — small, scrubby trees that grow in wet areas along stream beds — were starting to grow taller, because they were escaping predation by elk. In other areas, however, the willows continued to be heavily grazed upon. The same patchy changes were also seen with cottonwood trees, which also grow along streams.

“The more I looked at it the more I could see that what is going on may be an ecology of fear,” Ripple says. “The theory goes like this: the browser — in this case the elk — need to make behavioral decisions and tradeoffs as to how much time and energy to put into eating food versus how much time to be staying in safe places.” Those decisions affect where the animals concentrate their feeding efforts, and therefore the distribution of the vegetation they eat. “What we started noticing is that the plants were doing better where the terrain might favor the wolf a little bit more than the elk,” he says. For example, the elk might browse less in areas with poorer visibility (more dangerous to the elk because they can’t see if wolves are on the scene), or regions littered with heavy debris (a risk because it becomes an impediment to escape in the event of an attack).

Indeed, Ripple says, “we found that aspen were growing the tallest along streamside areas that had some downed woody debris or some downed logs nearby.”

Elk behavior and vegetation distribution aren’t the only factors impacted by the return of the Yellowstone’s wolves. Ripple suspects that the ripples of their recovery are reverberating throughout the entire ecosystem, in birds, fish, insects, as well as in other plants and animal species. Beavers, for example, are probably affected, he says. “The park service has been monitoring beaver since the wolves returned, and found that they have increased in numbers every year in the northern part of Yellowstone. Before the wolves returned, there really wasn’t much food for the beaver. But now with this growth of these plants — especially the willow — the beavers have more food, and they are also using the willows to build their lodges and their dams, which may be contributing to beaver population increases.”

“We are at the beginning of a grand ecological experiment,” Ripple says. “We were without wolves for seventy years, and we’ve just had them back in for 11 years, so we’re only just starting to see changes. It could take many decades for the ecosystem to recover.”

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Interview with filmmaker Bob Landis
http://www.studiodaily.com/main/searchlist/8699.html
FILM & VIDEO recently interviewed Bob Landis about wildlife cinematography, working in Yellowstone, and the experience of making “In the Valley of the Wolves.”

Yellowstone
http://www.nps.gov/yell/index.htm
Home page of Yellowstone National Park.

National Parks Conservation Association
http://www.npca.org/
With the mission of protecting and enhancing America’s national parks for future generations, the NPCA advocates for the national parks and educates decision makers and the public.

Wolf Page
http://www.nps.gov/yell/naturescience/wolves.htm
Official Yellowstone National Park wolves page.

State of the Wolves (PDF file)
http://www.nps.gov/yell/naturescience/upload/wolfrpt06.pdf
Yellowstone Wolf Project 2006 annual report.

Western Gray Wolves
http://www.fws.gov/mountain-prairie/species/mammals/wolf/
Information on western gray wolves from the U.S. Fish and Wildlife Service.

Wolf Conservation
http://www.nwf.org/graywolf/
Wolf information and conservation efforts from the National Wildlife Federation.

Idaho Fish & Game
http://fishandgame.idaho.gov/cms/wildlife/wolves/
Idaho Fish and Game Department wolf management.

Montana FWP
http://fwp.mt.gov/wildthings/wolf/default.html
Montana Fish, Wildlife & Parks’ wolf conservation and management site.

The Total Yellowstone Page – Wolves
http://www.yellowstone-natl-park.com/wolf.htm
Unofficial Yellowstone site, with a history of the wolves and a map of the locations of different packs.

Wolf Blog
http://www.forwolves.org/ralph/wolfrpt.html
Frequently updated wolf news reports from Ralph Maughan’s Wildlife Reports.

Wolves and Bears
http://www.grizzlydiscoveryctr.com/
The grizzly and wolf discovery center in Yellowstone.

Wolf Center
http://www.wolfcenter.org/
The Wolf Education and Research Center (WERC) is a unique educational facility on the Nez Perce Reservation in northern Idaho, home to the Sawtooth Pack.

Wolf Reintroduction
http://www.class.uidaho.edu/kpgeorge/issues/wolves_reintroduction/reintroduction_recolonization.htm
Information on the reintroduction of the wolf in the U.S.

Wolves of the World
http://www.wolf.org/wolves/index.asp
The International Wolf Center.

Wolf Web
http://www.wolfweb.com/
Web site with wolf-related games, stories, pictures, and activities.

Wolves in Nature Project – Trophic Cascades in Terrestrial Ecosystems
http://www.cof.orst.edu/cascades/
A research project to uncover the effect of Yellowstone’s wolves on the ecosystem. Trophic Cascades in Terrestrial Ecosystems is a research and educational program with the purpose of investigating the role of predators in structuring ecological communities.

Yellowstone Park Wolves
http://www.yellowstonenationalpark.com/wolves.htm
Web site on Yellowstone’s wolves, by production company Yellowstone Media.

Books:

Rick McIntyre. A Society of Wolves. Voyageur Press (1996).

L. David Mech. The Wolf: The Ecology and Behavior of an Endangered Species. University of Minnesota Press (1981).

L. David Mech and Luigi Boitani. Wolves: Ecology, Behavior, and Conservation. University of Chicago Press (2007).

Michael K. Phillips, Douglas W. Smith, Barry O’Neill, and Teri O’Neill. The Wolves of Yellowstone. Voyageur Press (1998).

Douglas W. Smith, and G. Ferguson. Decade of the Wolf: Returning the Wild to Yellowstone. The Lyons Press (2005).