Natural History: Endangered Wolves at a Glance

Where they live: wolves can live in a variety of habitats, including forests, grasslands, deserts, wetlands, and tundra. What’s most important is adequate prey, low human activity and tolerance for the species. With growing human populations and our increasing pressure on wild places, areas suitable for endangered wolves are shrinking. Wolves face enormous threats wherever they live because of wrongful claims about their appetites. Many believe that wolves compete with humans for food --  both livestock and their native prey, ungulates (hooved animals), such as deer and elk.

Grey Alpha Wolf pc Ray RafitiWhat they eat: wolves are carnivores that prey primarily on large ungulates such as elk, deer, and bison, but will also take smaller prey, including beavers and rabbits. At times, they even dine on insects, nuts, and vegetation. Wolves generally target the young, old, weak, or sick prey. Wolves pick vulnerable prey to minimize the substantial risks—injury and even death—they face while hunting elk. Their predation work improves the vigor of their prey populations and shapes their ecosystems. Wolves in the wild generally do not eat every day, but their average requirement is about 4 pounds of meat per day. New research shows that there may be a kind of wolf “social security,” as wolves peak in their hunting abilities at two to three years of age. Younger wolves provision for older wolves who are past their prime.

How they hunt: wolves, coursing carnivores, run long distances after their prey. This contrasts with ambush carnivores, such as cougars, that stalk and ambush their prey, and only run short distances using bursts of speed. A wolf-hunting territory can often be as large as 50 square miles. Where prey is scarce, wolf ranges can extend for 1,000 square miles. Wolves can travel up to 30 miles in a day, and at speeds as fast as 40 miles per hour.

Life in a pack: wolves are highly social animals, with the most important unit being the “pack.” A wolf pack is generally a family group that usually consists of a single alpha pair, which breed, and their offspring of different ages and sometimes a member adopted from another pack. An alpha female will bear, at most, one litter per year, of approximately 4-6 pups. Non-alpha wolves generally assist in rearing pups and do not themselves breed. Unrelated wolves may join a pack. By age three, members of the pack that they were born into usually disperse to find mates of their own. Wolves can reach ages of up to 13 years in the wild; but the average lifespan tends to be six to eight years or even lower. Wolves mate for life, but if one mate dies, the surviving wolf may look for a new mate. Wolves howl for a number of reasons, which include locating separated members of a pack and warning other packs to stay away.

Causes of death: sources of wolf mortality include disease, starvation, collisions with cars, conflicts with wolves or other carnivores, and – most importantly – killing by humans. In the U.S. endangered wolves are killed by private individuals and government agencies. Methods include shooting, leghold trapping, and aerial gunning. Several hundred wolves are killed each year in the continental U.S. In the Northern Rocky Mountains alone, the numbers range from 386 in 2008 to well over 500 in years 2009 and 2011. The numbers hide a deeper issue – wolves mean a lot to each other. The killing of an individual wolf has tremendous consequences that humans are just starting to grasp. Members of a pack can go to heart-breaking lengths to be together. Wolves can suffer physical, psychological, and emotional trauma. Wolf pack members associate with each other, and those packs maintain networks with other packs. Social animals, wolves experience disruption when fellow pack members are killed, which can affect not only individual packs but the entire network of wolves in a region. Social disruption can cause packs to disband and elimination of the breeding pair can lead to the loss of pups from starvation.

Table 1.

Wolf Mortality in the Northern Rocky Mountains, 2008-2011

(data: USFWS Annual Reports) 

2008

Livestock Protection1

Sport Hunters

Poach/Law Enforcement Investigation

Vehicle

Unknown/ Other/ Natural

Total

ID

108

0

13

10

18

149

MT

110

4

8

16

20

158

WY

46

11

8

2

12

79

Total

264

15

29

28

50

386

 

2009

Livestock Protection1

Sport Hunters

Poach/Law Enforcement Investigation

Vehicle

Unknown/ Other/ Natural

Total

ID

93

135

12

0

32

272

MT

145

72

16

8

16

257

OR

2

0

0

0

0

2

WY

31

0

7

0

2

40

Total

271

207

35

8

50

571

 

2010

Livestock Protection1

Sport Hunters

Poach/Law Enforcement Investigation

Vehicle

Unknown/ Other/ Natural

Total

ID

80

48

5

0

11

144

MT

141

0

13

11

13

178

UT

1

0

0

0

0

1

WY

40

0

13

0

5

58

Total

262

48

31

11

29

381

 

2011

Livestock Protection1

Sport Hunters2

Poach/Law Enforcement Investigation

Vehicle

Unknown Other Natural

Total

ID

63

200

11

7

0

281

MT

64

121

8

8

2

203

OR

2

0

0

0

0

2

WY

36

0

6

1

8

51

Total

165

321

25

16

10

537

 

Tangles with livestock: Much of the historic killing of wolves was motivated by livestock ranchers and carried out by federal agents and others. As bison and other ungulates were hunted out in the late 1800s and early 1900s and replaced by livestock, wolves had little choice but to feed on livestock. This prompted the concerted extermination effort which was almost completely successful throughout the lower 48 U.S. states. Today, reintroduced wolves generally hunt native prey, but the anti-wolf belief systems of the livestock industry have not faded away. Unsupported claims about wolves’ appetites for livestock has even lead to their delisting although wolves and all carnivores in total have killed less than one percent of the American cattle inventory.  See Northern Rocky Mountain Wolves Report pages 20 -24 for details.

Every wolf matters: Very intelligent, wolves are capable of a complex range of emotions, including joy, pleasure, happiness, empathy, compassion, sympathy, grief, sadness, and jealousy. Wolves are dependent on each other, whether their duties are on the hunt or back at the nursery. In 1998, a pack of Mexican wolves feverishly dug out around a log that the mother wolf was stuck in, successfully freeing her. Other fascinating accounts of relationships between wolves have been recorded. Ernest Thompson Seton wrote about a pair of wolves he hunted down in New Mexico, Lobo and Blanca. Lobo was caught only when Seton captured and killed his mate. While responsible for the deaths of this precious pair, Seton later wrote, “Ever since Lobo, my sincerest wish has been to impress upon people that each of our native wild creatures is in itself a precious heritage that we have no right to destroy or put beyond the reach of our children.”

photo credit: Gray Wolf: Ray Rafiti