Quick Facts

The wolves of Yellowstone and WolfQuest are gray (timber) wolves (Canis lupus).

APPEARANCE: Gray wolves are the largest of the canine (dog) family. They have a blocky muzzle and snout, and smallish, round ears. There is a wide range of coat colors which may vary geographically. A typical gray wolf's coat is gray mixed with tan, yellow, brown, and black markings. Some wolves may vary from solid black to a light gray color which can appear white. About half of the wolves in Yellowstone National Park are black and half are gray.

SIZE: 36-59 kg (80-130 lbs); 66-91 cm 26–36 inches) tall at the shoulder; 1.2-1.8 meters (4–6 feet) long from nose to tail tip. Females are smaller than males.

TOP SPEED: 50–60 kph (31–37 mph) and can sustain a slower lope for hours.

DIET: Carnivore. In the winter, 90% of Yellowstone wolves’ diet is elk. Summer prey includes more deer and smaller mammals. Sometimes wolf packs will hunt formidable bison when other prey is not available. They also scavenge, often feeding on carcasses from winter deaths or other natural causes.

AGE: Most Yellowstone Park wolves live about 4-5 years (outside of the park, the average is 2-3 years) and the oldest park wolf was 12 years.

More wolf facts at YS 24-1 Yellowstone Wolf Facts

Wolves are the largest of the three canids living in Yellowstone

People often mistake coyotes for wolves...obviously they have never see a wolf!

Wolves and coyotes are highly competitive but the smaller coyotes are usually good at staying out of the way of their much larger cousins' jaws. Fox avoid both wolves and coyotes and benefit from wolves keeping coyote numbers down.

Causes of death

The natural causes of wolf mortality are:

  • starvation (which kills mostly pups)
  • death from other wolves due to territorial disputes (top cause of death for adult wolves in the park)
  • diseases such as mange and canine parvovirus
  • injuries caused by prey
  • human-caused mortality (most common cause of death outside of the park)

photo: A wolf pup infected with sarcoptic mange in Yellowstone. credit: NPS

Yellowstone Wolf Packs

As of December 2018, there were 80 wolves in 9 packs. A biological count (April 1, 2019) was 61 wolves in 8 packs.

In general, wolf numbers have fluctuated between 83 and 108 wolves since 2009.

source: Yellowstone National Park

Radio Collars

Since the reintroduction of gray wolves to Yellowstone National Park in 1995 and 1996, radio collars have been used as the main tool for monitoring and research. Read more: Using Radio Collars to Study Yellowstone Wolves

Photo: Two collared wolves survey the Pelican Valley on a snowy day. redit: NPS/D. Stahler

Male vs. Female Wolves

Male wolves are about 20% larger than female wolves. They have larger, more muscled shoulders and neck as well as a blockier head with stronger jaws. This gives them an advantage hunting large prey like elk and bison.

Credit: NPS/artwork by Emily Harrington

Gray and Black Wolves

In Yellowstone, about half of the wolves have gray coats and half have black coats – but they are all gray wolves (Canis lupus).

Photo credit: NPS/Dan Stahler