June 17, 2022 at 2:59 pm
Many don’t realize it, but at some point or another, you’ve likely been in the presence of a bear in the Maine woods. Elusive and quick, bears often flee an area before you ever knew they were there. Maine has a robust and healthy black bear population that are well adapted to living near human development, and have a range and distribution that spans the entire state. Here are some facts about our state’s bears!
Biological and Ecological Facts:
- While three species of bear exist, Maine only has black bears (Ursus americanus) and are the most widely distributed species of bear on the continent.
- Not all black bears are completely black! Black bears in Maine are normally black, but they are often various shades of brown, cinnamon, cream colored in western populations, and are even white, and blue gray in color in coastal British Columbia and Alaska. They have a brown muzzle, and occasionally a white throat or chest patch or "blaze".
- Black bears have an impressive and keen sense of smell (2,100 times better smell than a human!) to help them search for food for miles away.
- Bears don’t hibernate, but they enter a state of torpor during the winter months. Torpor is a survival strategy meant to conserve energy during a time when food is very scarce. Bears enter a deep sleep where their body temperature lowers, their metabolism drops by 50 percent, and they live off their fat reserves that they accumulated during the summer and fall. Their heart rate and respiration slows to as low as nine beats per minute and one breath every 45 seconds. Eating, drinking, and creating waste essentially ceases.
- If a sexually mature female successfully mates in May and June, she will experience embryonic diapause. The ball of developing cells will pause and not implant onto the uterine wall until November! She will then give birth to one to four cubs after only about eight weeks of development.
- After emerging from the den in the spring, bears are constantly seeking food to restore weight lost over the winter. Black bears are opportunists, seeking and consuming anything from vegetation such as grasses, berries, acorns, and beechnuts, to insects such as ants and bees, to the occasional mammals and birds. Bears are even known to consume bird seed and trash – so make sure to clean up!
- As the summers progress, bears are triggered by shortening days and hormonal changes, warning them of the returning winter. Going into a state of excessive eating, called hyperphagia, bears will feed for 20 hours a day in preparation for winter, consuming up to 20,000 calories a day, to put on as much as 100 pounds in a few weeks!
Monitoring and Management Facts:
- Maine’s black bear monitoring program is one of the most extensive and longest-running programs of its type in the United States.
- For the last 45 years, MDIFW biologists have trapped and tracked over 3,000 bears to determine health and condition, estimate cub births every year, and determine cause-specific mortality rates.
- For six weeks in May and June every year, MDIFW biologists set numerous cable traps. These traps are checked for bears every single day. If a bear is being held by a cable trap, it will be quickly immobilized (sedated). Biologists fit male bears with ear tags and take measurements of size and weight. In addition to taking body condition measurements, female bears are collared, allowing biologists to find their den in the winter.
- When winter comes, biologists begin tracking the GPS collared females, using telemetry to seek out the den. They quickly sedate the sow (female) and take measurements of her and her cubs. This is the data that has allowed MDIFW to closely monitor the health of Maine’s robust black bear population for many years!