Isle Royale National Park

Isle Royale National Park

Natural World

Nature & Science

Nature and Science - an Overview

In the northwestern portion of powerful Lake Superior exists a unique and remote island archipelago. Isle Royale National Park preserves 132,018 acres of land-based wilderness that was federally designated on October 20, 1976. The park consists of one large island surrounded by about 400 smaller islands, it encompasses a total area of 850 square miles including submerged land which extends 4 1/2 miles out into the largest fresh water lake in the world. Due to Isle Royale's biological and ecological uniqueness, it was designated an International Biosphere Reserve in 1980. These isolated islands have barely 20 species of mammals compared to over 40 found on the surrounding mainland. Some species have come and gone, often due to the influences of humans. The heavily forested shoreline of Isle Royale appears similar to the mainland’s landscape prior to development. Gulls, ravens, and an occasional eagle or osprey dot the skies; squirrels, toads, mice, and spiders move about the forest floor.

The Ecological Study of Wolves on Isle Royale, now in its 46th year, is the longest running large mammal predator-prey study on earth. Research has shown that all members of the Isle Royale wolf population have descended from a single female, which arrived during the late 1940s. This intense level of inbreeding has led to a 50% loss of genetic variability within the population today. Genetic information suggests that the island’s moose population is most closely related to moose in northwestern Minnesota…perhaps challenging the long-held idea that moose swam across the lake to reach Isle Royale. Did humans bring them here?

A venture by foot, canoe or kayak into the parks interior can transport one back thousands of years into it’s prehistoric past. Around 11,000 years ago, 2 miles of ice lay on top of Isle Royale, pressing it down into the earth and sculpting its topography. The same ice sheet gave birth to powerful Lake Superior as well as hundreds of inland lakes, ponds and bogs. The Greenstone Ridge, which forms the backbone of Isle Royale, is thought by many geologists to be a portion of the largest lava flow on earth.

All in all, Isle Royale is a fascinating ecosystem, responding to influences seen in very few places in all of North America or the world.

Isle RoyaleNational Parkis significant because:

  • It is a remote and primitive wilderness archipelago isolated by the size and power of Lake Superior.
  • Isle Royale is world renowned for its long-term wolf/moose predator/prey study. The park offers outstanding possibilities for research in a remote, relatively simple ecosystem where overt human influences are limited.
  • Park waters contain the most productive native fishery and genetically diverse trout populations in Lake Superior.


Natural Features & Ecosystems

Lake Superior has shaped Isle Royale's rugged rocky shore as well as created its isolation. Crossing Lake Superior was not easy for the Island's first visitors. These were hunter-gatherers that came for copper, game and berries thousands of years ago.

"This is the first season of my life that father has taken me to the floating island. The trip across Kitchi Gummi (Lake Superior) was calm. The last snows of winter have all but melted. We pull our canoes made of birch bark ashore on red sand beach. Shesheeb ( ducks)  float near by. Many in our party gather large round stones. They carry them over the jagged porous ridges away from the craggy shore and into the forest. I notice something shimmering beneath the waters. It is bright and blinds me when the sun hits it through the rippling waves. I reach for it through the water. I grasp it tightly. It is cold, heavy, and solid, yet nothing like the jagged stones around it. My father rejoices when he see's what I've found . He holds it to the sky shouts in the air "miskwabik!" (The red metal)."


As we paddle through the mist of inland Lake Ritchie a loon calls, or was it a wolf? Some loon calls sounds similar to a wolf's howl. There is an abrupt splash behind us. The boat rocks as we turn to look. Perhaps we startled a beaver, a duck or an otter. We stop paddling but the canoe continues to drift.

The tops of pointy conifers and paper birch are barely discernable through the quiet morning fog. The sloshing we hear on the far shore can only be a moose. Yes, we see it now, climbing from the boggy marsh near the Indian Portage Trail. It is a cow, with a calf in tow, now tromping through the abundant thimbleberry ground cover. An osprey circles high above, its eyes keenly scanning the waters and rocky shore. It soars ever higher, over the Greenstone Ridge toward Canada and the northern shores of great Lake Superior. 

Isle Royale's Wilderness provides habitat for many creatures. The island's isolation creates simple ecosystems. Fourteen or possibly more species of mammals occupy the island. All of Isle Royale's creatures create their own natural survival/extinction saga. As recent as 1927 caribou and coyote dotted the landscape. The island now is devoid of these creatures, having given way to other species.

The island was once called Minong by past cultures, which translated means “a good place to pick berries”. Why haven’t black bear found their way to this place? There are also no raccoon on Isle Royale. These creatures thrive just 12 miles away in Minnesota and Ontario, Canada.

The beaver have used up much of the softwood forest and aquatic environment that once supported larger numbers. The moose threaten to strain their limited food supply. A walk along most trails will reveal evidence of this in the form of "moose browse". And what will become of the moose which currently number 450, while wolf numbers hover at 30? Step inside for a closer view. Minong awaits..


As we move briskly along the trail my eyes are drawn to a patch of orange through the evergreens near the rocky shore. It looks as though someone had painted the craggy stone from my vantage. Perhaps some sort of freshwater coral? Our gaiters protect us from the thorns of devils club as we approach for a closer look. We feel miniaturized by the cow parsnip that towers over our heads in large white blooms. The broad leaves of the aster rule the groundcover, rivaled only by the maple shaped leafs of thick thimbleberry. At last we are standing over the patch of bright orange. It is a fungus called lichen. On closer inspection we see it is everywhere in shades of orange, light pink and green. We attempt not to step on it as now all the shore seems alive.

Environmental Factors

On a clear day from the Ojibway fire lookout you can see miles in every direction. The wind does not stop. The sturdy steel structure sings and creaks with each strong gust. To the west is Sargent Lake. To the north is Canada. To the South is the Rock Harbor lighthouse (circa 1855) nearly 2 miles away. Like the more modern lookout, the old light was built to warn of danger.

Inside the humble little shack atop the tower are an incongruous variety of solar powered high tech gadgets. Some carefully monitor the air quality, some record weather data. This is much more than a fire lookout; it is in fact the most isolated atmospheric monitoring station in all of the National Park Service.