A gray wolf trotting through fresh snow in Yellowstone National Park NPS / Jacob W. Frank

The case for wolves.

Gray wolves were wiped out across most of the West a century ago. Their return to Idaho and Yellowstone has taught scientists how much one predator holds a landscape together.

Support wolves See the ripple effect

Gone, then back

By the 1920s, government trapping and poisoning programs had removed wolves from Yellowstone and most of the Northern Rockies.

With no predator to keep them moving, elk settled into the valleys and stream bottoms and stayed there. They browsed young aspen, willow and cottonwood down to the ground year after year. Researchers using tree rings later found that almost no new aspen grew into mature trees in Yellowstone after the wolves disappeared.

In 1995 and 1996, wildlife officials released wolves captured in Canada into Yellowstone and central Idaho. Idaho is now home to one of the largest wolf populations in the lower 48, ranging through the Frank Church, the Sawtooths and the forests of the Panhandle.

31wolves released into Yellowstone in 1995–96
15,000 → 6,000northern Yellowstone elk herd, early 1990s to about 2010, letting browsed streamsides recover
2×the land area covered by willow in northern Yellowstone between 1991 and 2006
About 1,550wolves estimated in Idaho, which in 2023 adopted a plan to cut that number to roughly 500
Wolf number 10 walking through grass and snow inside the Rose Creek acclimation pen
Wolf #10, one of the first wolves brought back, in Yellowstone's Rose Creek acclimation pen in February 1995. NPS / Jim Peaco

The ripple effect

Ecologists call it a trophic cascade: a change at the top of the food chain that travels all the way down to the soil and water.

A collared gray wolf watching a herd of wintering elk
A collared wolf keeps an eye on wintering elk at the National Elk Refuge in Jackson, Wyoming. USFWS / Tony and Ann Hough

  1. Wolves return

    Packs hunt elk and deer, most often catching the old, the young and the sick.

  2. Elk keep moving

    Elk numbers drop and the herds avoid lingering in risky spots like narrow stream bottoms.

  3. Trees grow back

    Aspen, willow and cottonwood saplings finally grow tall enough to escape browsing.

  4. Beavers return

    More willow means food and building material for beaver colonies, which dam streams and raise water tables.

  5. Life fills in

    Shaded, stable streams hold more fish and amphibians, and songbirds and bears feed on the new growth and berries.

Scientists still debate how much of Yellowstone's recovery is due to wolves alone. Bears, cougars, hunters, drought and a growing bison herd all play a part, and aspen has come back strongly in only some places. But researchers who have studied the park for decades agree that wolves were a key piece that had been missing.

Why wolves are worth supporting

Wolves aren't just a symbol of wild country. They do real work on the land.

Healthier deer and elk herds

Wolves tend to take weak and sick animals, which can slow the spread of disease and leave stronger animals to breed. In the hard winters of the 1980s and 90s, before wolves came back, large numbers of Yellowstone elk starved after overgrazing their range.

Food for the whole neighborhood

A wolf kill feeds grizzly and black bears, eagles, ravens, magpies, foxes and even beetles. Scavengers find a steadier supply of food through the winter and into spring.

Cleaner, cooler streams

Taller willow and cottonwood shade the water, hold banks in place and slow erosion, which helps trout and other fish that need cold, clear streams.

Balance among predators

Wolves push back coyote numbers. In Yellowstone, coyotes dropped by about half after wolves returned, easing pressure on pronghorn fawns, rodents and ground-nesting birds.

Wild places worth visiting

Yellowstone's Lamar Valley is one of the best places in the world to see wild wolves, and wolf watchers bring visitors to nearby towns in every season.

A piece of our heritage

Wolves lived across nearly all of North America before people pushed them out. Their recovery is one of the clearest successes of the Endangered Species Act.

A wolf standing in the steam of Yellowstone's Lower Geyser Basin
The lead female of Yellowstone's Canyon pack in the Lower Geyser Basin, 2015. NPS / Jim Peaco

Living alongside wolves

Supporting wolves doesn't mean ignoring the people who raise livestock in wolf country. Ranchers, conservation groups and wildlife agencies across the West are using practical, non-lethal tools that cut losses for ranchers and keep wolves out of trouble.

  • Range riders
  • Livestock guard dogs
  • Fladry fencing
  • Lights and scare devices
  • Careful calving and carcass removal
A black wolf searching the ground for ground squirrels
A black wolf hunting ground squirrels on the National Elk Refuge. USFWS

Support wolves

The groups below are 501(c)(3) nonprofits, so your gift is generally tax-deductible. One works right here in Idaho; the other works across the country.

Portrait of a gray wolf
Gary Kramer / USFWS

Living with Wolves

Based in Sun Valley, Idaho, Living with Wolves teaches the public about wolves, runs a wolf museum in Ketchum and works on ways for wolves and people to share the land.

Donate to Living with Wolves

Defenders of Wildlife

A national group that helps ranchers pay for range riders, guard dogs and fladry, and fights for wolf protections in Congress and the courts.

Give to protect gray wolves

You can also help without donating: find out who to contact about wolf policy in your state, and share accurate information about wolves with friends and neighbors.