Chapter 1
The Pack Is a Family
Who lives in your home with you? A wolf lives with its family, too. That family is called a pack.
A family, not a gang
A wolf pack is a family. The mother and father lead the group. Their pups follow. Older brothers and sisters help too. Most packs have four to ten wolves.
The parents choose where to travel and when to hunt.
Born in the dark
In spring, wolf pups are born in a den. Each newborn weighs about one pound. Its eyes and ears are sealed shut.
The mother picks or digs the den weeks before her pups arrive. A tunnel leads to a room in a hillside, under roots, or among boulders.
Growing up outside
At about three weeks old, pups first peek out of the den. Later, the pack moves them to a meeting spot near water.
There the pups wrestle, chase, and pounce. These games build muscles and hunting skills.
Everyone helps
The whole wolf family raises pups. Older siblings babysit while adults hunt and bring food. This teamwork helps pups survive.
Adults swallow meat after a hunt and carry it home. When pups lick and nuzzle an adult's mouth, the adult brings the food back up.
Chapter 2
Growing and Playing
Do you like to wrestle, chase, or play tag? Wolf pups do too. Their games help them grow strong.
Milk, then meat
Pups drink milk for the first five to nine weeks. Then adults feed them meat. A mother usually has four to six pups.
Many pups do not survive their first year. Hunger, sickness, and cold are the main dangers.
Built for the wild
A grown wolf weighs 60 to 145 pounds. It stands about waist-high to a grown-up. It is about six feet long from nose to tail.
Wolves can be gray, black, white, brown, or tan. Yellowstone's wolves are about half gray and half black.
Two coats in one
A wolf's soft undercoat traps body heat. Longer guard hairs on top shed rain, snow, and wind.
The guard hairs stay all year and give a wolf its color. The undercoat is shed and grows back with the seasons.
Staying close
Adult wolves chase, wrestle, and jaw-spar with each other. Play eases tension and keeps family bonds strong.
Wolves also lick and gently nibble each other's fur. This grooming removes dirt and ticks. It shows care and trust, too.
Chapter 3
Senses and Voices
Close your eyes and listen. Far away, a wolf is howling to find its family. Wolves also send messages with smells and with their tails.
A voice that carries
Wolves howl to find each other. A howl can travel up to ten miles across open land. Each wolf has its own voice, so packmates can tell who is calling.
Howling also tells other packs to stay away. When the whole family howls together, the voices can make the group sound bigger than it really is.
More than a howl
Wolves make four main sounds. A howl carries far. A bark warns of danger. A growl says 'stay back.' A whimper is a soft, friendly greeting.
Before a hunt, the pack often gathers and howls with yips and yelps. This rally brings the family close.
The many jobs of a tail
A wolf's tail shows how it feels. A tail held high shows confidence. A tail tucked between the legs shows fear.
The tail also helps a wolf balance during sharp turns as it runs.
A world of smell
A wolf's nose holds about 200 million smell sensors. A human nose has only about 5 million. Wolves can smell another animal more than a mile away.
With their noses, wolves can find food under snow and read scent marks from other packs. They can even tell one family member from another.
Chapter 4
Hunting and Territory
Picture your whole town. A wolf pack's home can be even bigger! The family hunts as a team across all that land.
Smell messages
Wolf packs leave scent marks along their borders. These work like 'no trespassing' signs. Other wolves read the chemical messages to learn who passed by.
Wolves also have scent glands on their toes, tail, and skin. Leading wolves may leave a mark every two minutes as they travel.
Home range
A wolf pack's territory can be bigger than a whole city. In the Great Lakes, territories cover 25 to 150 square miles. On the Arctic tundra, they can be more than 1,000 square miles.
Packs guard their borders with howls and scent marks. If another pack crosses the line, a fight can follow.
Snowshoes and swimmers
A wolf's large paws spread wide like snowshoes. They help wolves cross deep snow that bogs down elk and deer.
Webbing between the toes helps on soft snow and when swimming across streams. Claws that never pull in grip rough ground.
Hunting as a team
Wolves hunt together. Some pack members chase prey toward the others. Wolves hunt elk, deer, moose, and caribou. A kick from such a big animal can badly hurt a wolf.
Most hunts fail. In long studies in Yellowstone, about four out of five hunts ended without a catch.
Chapter 5
Room to Roam
Where would you go if you left home to start your own family? Many young wolves do just that. Wolves need room to roam and enough prey to eat.
Leaving home
Many young wolves leave the pack when they are one to three years old. Each one travels alone to find a mate and start a new family.
This journey is called dispersal. It keeps wolves from mating with close relatives. A wild wolf lives about six to eight years.
Forests, tundra, and beyond
Wolves live in forests, mountains, grasslands, and tundra. They need enough prey and enough space. Open tundra holds caribou and muskox.
Arctic wolves have white coats that blend with snow. Stocky bodies and small ears help them save heat.
Wolves change the land
When wolves came back to Yellowstone, elk stopped lingering near streams. In some places, willows and aspens began to grow back. Scientists call a chain reaction like this a trophic cascade.
More willows meant more food and dam wood for beavers. So wolves helped bring beavers back to Yellowstone, though other things helped too.
Wolves today
Around 200,000 to 250,000 gray wolves live worldwide. Canada has about 60,000.
In 2020, Colorado voters chose to bring wolves back. Ten wolves were released in 2023. Wolves are also returning across Europe.
Sharing the leftovers
Wolves often leave food behind after eating. Ravens, eagles, foxes, coyotes, and bears all scavenge from wolf kills.
Bears and wolves sometimes compete for food. A pack can sometimes drive a bear off a kill. But a big grizzly can push a whole pack away.
Your next question
Choose a picture. Say what you see. Ask a question it cannot answer. Find a helpful page or explore with a grown-up.
Wolf quiz
Who leads a wolf pack?
Show the answer
The mother and father.
Can newborn wolf pups see?
Show the answer
No. Their eyes are sealed shut.
How does the pack feed its pups?
Show the answer
Adults swallow meat and bring it back up.
How far can a wolf's howl travel?
Show the answer
Up to ten miles.
How many smell sensors does a wolf's nose have?
Show the answer
About 200 million.
How big can a wolf pack's territory be?
Show the answer
More than 1,000 square miles on the tundra.
Glossary
- den
- An underground room where wolf pups are born.
- dispersal
- When a young wolf leaves its birth pack to start a new family.
- guard hairs
- The long outer hairs that shed water and block wind.
- pack
- A family group of wolves, led by the mother and father.
- regurgitate
- To bring swallowed food back up to feed pups.
- scent mark
- A smell signal left to tell other wolves a territory is taken.
- trophic cascade
- A chain of changes that spreads from a top predator through nature. In Yellowstone, returning wolves helped some willows grow back.
How we know
A useful explanation starts with evidence. Ask what was seen, and what still needs a test.