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The Fascinating World of Black Bears in the Apostle Islands

Updated: Jan 9

Explore the dynamic population and behavior of black bears on the Apostle Islands, from their omnivorous diet and strong swimming abilities to their sensitivity to overcrowding and avoidance of human contact. Follow the latest research on these majestic creatures and discover their role in the island ecosystem.

Black bears (Ursus americanus) are the most common and widely distributed bear species in North America. They can vary in color, with the black phase being the most common, but they can also be shades of brown or even white. Male black bears typically weigh between 250 and 400 pounds, while females typically weigh between 150 and 225 pounds. These bears are omnivorous and rely heavily on their sense of smell to find food. They are able to run at speeds of up to 30 mph and have curved claws that allow them to climb trees. Black bears are also strong swimmers, which allows them to inhabit islands.


The population of black bears on an island can grow quickly from just a single pair of bears to very high densities, but it can also eventually decline. The population of black bears on Stockton Island has been studied for many years and may be going through this cycle of growth and decline. In the 1970s, it was thought that there was only a single pair of bears on the island, but the population grew to a peak of 31 bears in 1994. The population appeared to be stable between the mid-1990s and 2002, with around 26 bears, but a study in 2010 found that the population had decreased by 50% and the number of female bears (sows) had decreased by 84%.


In contrast, the black bear population on Sand Island nearly doubled between 2002 and 2010, going from 6 to 10 bears, and the population of 18 bears on Oak Island is particularly high. For many years, Stockton Island was thought to have the highest population density of black bears in Wisconsin and among the highest in North America, but that title has now been passed to Oak Island, with Sand Island coming in a close second. A new round of bear research began in 2020 and will continue through 2022, with a larger research area on the mainland and the inclusion of Basswood Island in the study. It will be interesting to see what this research reveals.


This information was obtained through DNA analysis of bear hair samples. Researchers set up barbed wire snares on several islands and baited them with fish oil-soaked logs to attract bears. When the bears investigated the bait, they left behind a sample of hair on the barbed wire. Scientists regularly collected the hair samples for analysis, which not only allowed them to determine the number of bears on the islands, but also their sex and relatedness.


10 Fun Black Bear Facts.

  1. Black bears are the most common and widely distributed bear species in North America.

  2. They can vary in color, with the black phase being the most common, but they can also be shades of brown or even white.

  3. Adult male black bears typically weigh between 250 and 400 pounds, while females typically weigh between 150 and 225 pounds.

  4. Black bears are omnivorous and rely heavily on their sense of smell to find food.

  5. They are able to run at speeds of up to 30 mph and have curved claws that allow them to climb trees.

  6. Black bears are also strong swimmers, which allows them to inhabit islands.

  7. The Apostle Islands in Wisconsin are home to a high concentration of black bears.

  8. The population of black bears on Stockton Island saw a significant increase in the 1980s and 1990s, growing from just two animals in 1984 to a high of 31 non-cub bears in 1994.

  9. Black bears are sensitive to overcrowding and try to avoid human contact.

  10. Scientists and wildlife managers continue to study black bears and their populations in the Apostle Islands to better understand their behavior and habitat needs.


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