American Black Bears in eastern North America are typically black overall with a brown muzzle and sometimes a white chest patch. Their feet are large and well padded, with moderately-sized curved claws. Male Black Bears generally range in weight from 130 to 600 pounds and females from 100 to 400 pounds. In Massachusetts, males average 230 pounds and females 140 pounds. Lengths range from 3½ to 6 feet and shoulder height from 2½ to 3½ feet.

Black Bears have good eyesight and hearing and have an extraordinary sense of smell which is used to locate food and recognize potential danger. They are excellent climbers and commonly use trees for resting, escape cover and to protect their young.

The bear population has grown from about 100 in the early 1970s to over 4,000 when last estimated in 2011.  The rapid population growth and range expansions is due to a variety of factors including increased legal protection, changes in forest structure and composition, and increased availability of supplemental fall foods.


The American Black Bear (Ursus americanus) is the only bear found in Massachusetts. They are found in 40 US states, 12 Canadian provinces and 13 states in Mexico. Black Bears have reoccupied 69% of their historical range in North America and 44% of their historic range in the US.  Bear have recently reoccupied much of their historical range in the Northeast, and their status is generally favorable. In Massachusetts, Black Bears have been increasing in numbers and distribution for the past 35 years. They live and breed in Worcester County, northern Middlesex County and west to the Berkshires. Bears, mostly young males, are frequently seen in eastern Massachusetts communities along Route I495 and as a few individual have made it as far east as Newton and Cape Cod. As the bear population grows and expands, breeding females will continue to move east, thus reestablishing historic breeding bear range in many eastern parts of Massachusetts.


Black Bears mate between mid-June and mid-July. A dominant male will breed with several females. After breeding, the fertilized egg develops into a ball of cells called a blastocyst which remains free-floating in the uterus for several months; a trait known as delayed implantation. If the female is well-nourished, the blastocyst implants in the uterine wall in late November; small feeble cubs are born in the den in mid- to late January. Litter sizes range from 1 to 4 cubs. Cubs exit the den in early- to mid-April and remain with the mother for about 17 months, at which time she comes into estrus again and chases the yearling bears away. Young females typically take up residence near their mother's home range but the young males disperse many miles. Females typically first give birth at 3 or 4 years of age.


Massachusetts bears are typically active in daytime during spring and fall, but are more active during dawn and dusk hours in summer. Males may be nocturnal during the summer months. Typical spring habitats in Massachusetts include wetlands with lush emergent vegetation and hardwood areas with leftover nuts from the previous fall. In summer, wetlands and cutover areas with berry crops are preferred. Corn fields and oak, beech, or hickory stands are favored in fall. Bears have excellent long-term memory and are capable of recalling the location of periodic food sources years after the first visit.

In Massachusetts, adult females found west of the Connecticut River use home ranges averaging 9 to 10 square miles, while adult males may have ranges exceeding 120 square miles.  Home ranges of females east of the Connecticut River may over 100 square miles.  Depending on food availability, Massachusetts bears typically enter the den between mid-November and mid-December and exit between February and mid-April.  Pregnant females often enter dens the earliest (sometimes as early as mid-October) and those with newborn cubs (that were born in the winter den) typically exit in early April. Pregnant females will ALWAYS enter a den, as this is where they give birth. If food is available throughout the winter, males, lone females that are not pregnant, and females with yearlings may be active during the winter.  Bears are not true hibernators – they can rouse easily and their body temperature does not drop substantially, but they can remain in the den without eating, drinking, or excreting for nearly 6 months.  Bears in Massachusetts commonly den in brush piles, under fallen trees, rock piles, or in mountain laurel or rose thickets. 

In the vast majority of cases, Black Bears are not fierce. If approached by a human, their first response is usually to flee. In fact, in a wooded area, bears often disappear long before they are seen. Black Bears rarely harm people, although defensive attacks can occur when people tease or closely approach bears in parks or campgrounds or if bears are startled at close range. Female Black Bears defend their cubs by sending them up a tree. Sows may huff and blow and make short rushes at people who get near the cubs. Deliberate predatory attacks are extremely rare, but have occurred in other states.  

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on black bear problems and control.

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Find guidelines for the prevention and management of bear damage.

For additional information and advice on black bear management, problems, and damage control strategies in Massachusetts, contact your local MassWildlife District office.