Article
Daniel Conjanu/The National Parks of Lake Superior Foundation via AP Image

Hope for Howlers

Scientists bring new wolves to an island to help save a stranded pack

By Kimberly Y. Masibay
From the March 2021 Issue

Learning Objective: Students will identify and label coordinate points and graph ordered pairs on a coordinate plane representing the travels of a pack of wolves.

Lexile: 880L; 680L
ecosystem

All the living and nonliving things that interact with one another in a place

origin

The point at the center (0,0) of a coordinate grid

coordinate plane

A two-dimensional surface formed by the intersection of a vertical and horizontal number line

axes

The horizontal number line (x-axis) and the vertical number line (y-axis) on a coordinate plane

isolated

Alone, with nothing nearby

ordered pair

A pair of numbers used to locate a point on a coordinate grid. Ordered pairs are written in the form (x,y), where x shows how many units to move horizontally from the origin and y shows how many units to move vertically from the origin.

Example: The ordered pair (4,5) is located 4 units horizontally then 5 units vertically from the origin.

monitor

Regularly check over a period of time

rugged

Having a rough, uneven surface

mainland

A large piece of land such as a continent, especially when compared with an island nearby

population

All the members of a particular species that live in one place

declined

Became less

veterinarian

A doctor for animals, often shortened to “vet”

shot up

Grew quickly in amount or size

lumbering

Moving heavily and slowly

Daniel Conjanu/The National Parks of Lake Superior Foundation via AP Image

Biologists release a wolf on Isle Royale in 2019.

A small airplane landed on a rugged island in Lake Superior. Workers unloaded a large crate. Inside was a male wolf. Just a few days earlier, he’d been captured in the woods of mainland Michigan. A veterinarian had examined him and fitted him with a tracking collar. The wolf had arrived at his new home.

Isle Royale is a small, isolated island off the coast of Michigan. You can reach it only by boat or plane. In the past, a pack of about 25 wolves lived there. But over the past decade, their numbers declined. Without these predators, the number of moose on the island shot up. Now the moose graze on too much of the island’s plant life. The ecosystem is out of balance.

A small airplane landed on a rugged island in Lake Superior. Workers unloaded a large crate. Inside was a male wolf. He had been captured just a few days earlier. The scientists caught him in the woods of mainland Michigan. A veterinarian had examined him. The veterinarian had also put a tracking collar on him. The wolf had arrived at his new home.

Isle Royale is a small island. It’s also isolated. The island is located off the coast of Michigan. You can reach it only by boat or plane. A pack of about 25 wolves used to live there. But the wolves’ numbers declined over the past decade. The number of moose on the island shot up without these predators. Now the moose are eating too much of the island’s plant life. The ecosystem is out of balance.

Daniel Conjanu/The National Parks of Lake Superior Foundation via AP Images (Isle Royale); MI DNR John Pepin/NPS/USGS

Biologists measure a gray wolf captured on mainland  Michigan in the fall of 2019.

Scientists decided to act. To help Isle Royale’s wolves recover, the National Park Service (NPS) has been transporting healthy wolves to the island. Within the next few years, the NPS plans to move 20 to 30 adult wolves to Isle Royale.

Scientists decided to act. The National Park Service (NPS) has been moving healthy wolves to Isle Royale to help the island’s wolves recover. The NPS plans to move 20 to 30 new adult wolves to Isle Royale within the next few years.

Stranded Pack

USFWS/Courtney Celley/NPS/USGS

A veterinarian examines a captured wolf’s teeth.

Wolves first arrived on Isle Royale about 70 years ago. They traveled from the mainland over an ice bridge that formed on Lake Superior. When spring arrived, the bridge melted, leaving the pack trapped on the island.

Decades ago, new ice bridges would form during frosty winters. Wolves could come and go from the island, creating new mating pairs. But as the climate has warmed, winter temperatures haven’t been cold enough for ice bridges to form. 

Wolves first arrived on Isle Royale about 70 years ago. They traveled from the mainland. They crossed a bridge made of ice that formed on Lake Superior. The bridge melted when spring arrived. The pack was trapped on the island.

New ice bridges formed during cold winters in the past. Wolves could come and go from the island. They could find new mates. But the climate has warmed. Winter temperatures have not been cold enough recently for ice bridges to form.

Isle Royale

Jim McMahon/Mapman®

Isle Royale National Park is a 45-mile-long island in Lake Superior off the coasts of Minnesota and Michigan. It can be reached only by boat or aircraft. 

Isle Royale National Park is a 45-mile-long island in Lake Superior off the coasts of Minnesota and Michigan. It can be reached only by boat or aircraft. 

Over time, the wolves stuck on the island grew to have more and more health problems. There weren’t enough wolves to support a healthy population. By 2018, only two wolves were left. 

The wolves stuck on the island grew to have more and more health problems over time. There weren’t enough wolves to support a healthy population. Only two wolves were left by 2018.

Healthy Howls

John Vucetich

Wolves on Isle Royale prey upon a moose, which can weigh up to 1,000 pounds.

As of September 2019, 17 wolves called Isle Royale home—the 15 introduced by the NPS plus the original pair. But even with more wolves, it’s going to take time to slow the growth of the island’s moose population. 

When researchers visited Isle Royale in the late spring of 2019, they found an alarmingly large number of moose. Plus, they were concerned about the damage the moose were doing to the forest.

Seventeen wolves lived on Isle Royale in September 2019. These wolves included the 15 introduced by the NPS plus the original pair. But it’s going to take time to lower the number of moose on the island.

Researchers visited Isle Royale in the late spring of 2019. They found a huge number of moose. The researchers were concerned about the damage the moose were doing to the forest.

NPS/Jacob W. Frank/USGS

A female wolf emerges from her crate on Isle Royale, her new home.

Quiet, speedy wolves can be harder to find and monitor than large, lumbering moose. So scientists track the new wolves by fitting them with GPS collars. 

The team didn’t see any wolves during their trip early in 2019. But for the first time in years, they heard howling in the distance at night. Hopefully, it’s the sound of a healthier Isle Royale.

Wolves are quiet and fast. They can be harder to find and monitor than large, lumbering moose. So scientists track the new wolves by putting GPS collars on them.

The team didn’t see any wolves during their trip early in 2019. But they heard howling in the distance at night for the first time in years. Hopefully, it’s the sound of a healthier Isle Royale.

Now You Try It

Use the coordinate plane and compass at right to answer the questions.

Use the coordinate plane and compass at right to answer the questions.

Scientists start tracking a new wolf at point A. What are the coordinates of point A?

Scientists start tracking a new wolf at point A. What are the coordinates of point A?

A. The wolf joins up with a pack 1 unit east and 2 units north of point A. What are the coordinates of the pack? 

B. Plot this point on the grid and label it point P.

A. The wolf joins up with a pack 1 unit east and 2 units north of point A. What are the coordinates of the pack? 

B. Plot this point on the grid and label it point P.

A. The pack moves 5 units east and 4 units north of point P while hunting moose. Plot the new coordinates and label the point M.

B. How many units east of point A has the new wolf moved?

A. The pack moves 5 units east and 4 units north of point P while hunting moose. Plot the new coordinates and label the point M.

B. How many units east of point A has the new wolf moved?

A. The pack returns to their den after the hunt, 6 units west and 5 units south of point M. Plot the new coordinates and label the point D. 

B. Connect the points to trace the wolf’s path. What do you notice? 

A. The pack returns to their den after the hunt, 6 units west and 5 units south of point M. Plot the new coordinates and label the point D. 

B. Connect the points to trace the wolf’s path. What do you notice? 

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