American Black Bear

Range and Habitat

The black bear once occurred over most of North America from Alaska and Canada south
into the central regions of northern Mexico, but now it is absent from parts of the
central and north central U.S. The black bear occurred throughout the Adirondack Park
in all terrestrial communities, and at all elevations, but is most abundant in the
wilder areas of the Park. The annual harvest by bear hunters with in the Park averages
500-600. The black bear prefers dense, secluded forests. Mixtures of forest openings
with luxuriant raspberry or blackberry plants and old-growth timber providing mast
(acorns, beechnuts) and dens, affords ideal habitat.

Food Habits

Adirondack black bears eat a wide variety of foods. Approximately 90 percent of their
diet is plant material consisting of not less than 30 different plant species. The
remainder is primarily insects, but bears also will scavenge carcasses of larger animals,
an, if the opportunity arises, prey upon live white-tailed deer fawns, small woodland
mammals, and beaver. Bears are very will adapted for finding and gathering food. They have a keen sense of smell, powerful forearms, long claws, tremendous endurance,
and are adept with their tongue and paws. As a result, black bears can dig out plant
tubers or small rodents, tear apart rotten logs to find grubs, climb trees and break
off branches to gather nuts, “pick” raspberries and blueberries, and travel long distances
in search of new food resources.

In spite of their large size and tremendous strength, most items bears eat are small,
and as a result a bear has to eat a lot at one sitting. It is not uncommon for bears
to gorge themselves on a particular berry species for several days, or even weeks,
eating virtually nothing else before moving on to another location or a different
food resource. Although generally solitary animals (except for females with young),
several bears may congregate in a localized area of high food abundance for short
periods of time.

Black bears are very much in tune with their surroundings. Seasonal changes in the
plant community result in varied food availability for bears. When bears emerge from
their winter dens in early April, it takes a couple of weeks for their digestive system
to “start-up” again after being shutdown all winter. Food is scarce in spring; there
are no ripe berries or nuts as yet.

The first green vegetation to appear on the forested landscape includes tender young
shoots and leaves, aspen catkins, succulent grasses and fern fiddle heads. As summer
arrives, wild strawberries and juneberries, along with lush vegetation constitute
the bulk of bears’ diet. In July, pin cherries, sarsaparilla berries, and blueberries
become available. Later on in summer, red raspberries ( a key fruit species for bears),
choke cherries, scarlet elder berries, dogwood fruits and blackberries ripen. In September,
American mountain-ash berries, black cherries, mountain holly fruits, and hazelnuts
are sought out by bears. In mid to late fall beechnuts, and in some areas acorns,
are key food resources along with wild apple and the fruits of the viburnums, particularly
arrowwood and wild raisin.

By mid-novemeber food resources are becoming scarce and the Adirondack black bears,
now fattened for winter, begin to seek out a favorable den site. Feeding activity
has nearly ceased and the bears’ metabolic rate begins to slow in preparation for
winter hibernation. Pregnant females are usually the first to enter their dens followed
by barren females and then males. By Thanksgiving most Adirondack black bears are
secure in their dens waiting out the long winter.

Food abundance and diversity is a critical part of Adirondack black bear habitat.
Food availability also plays a key role in population dynamics. Lack of adequate food
resources has been shown to have a direct negative effect on female reproductive rates,
age of maturity, survival of young, and growth. Indirectly, food resource limitations
in the wild can lead to increased bear/human interactions. Some hungry bears will
seek out landfills, garbage cans, or public campsites as alternative sources of food.
Many humans are intolerant of bears around their homes and camps, and the bear is
usually the loser in any confrontation. Feeding bears acclimates them towards humans
and their surroundings, increasing the potential of nuisance bear problems. Removal
of excessive numbers of nuisance bears can have a negative impact on the population.

Public lands within the Park, protected under the state constitution from development
and timber harvesting, often support mature forests dominated by shade tolerant species
such as beech. Large mature trees provide abundant fruit/nut crops. Over mature and
fallen trees harbor insects and small mammals. In contract, a large segment of the
privately-owned land within the Adirondack Park is actively managed for timber production
and/or a wide variety of outdoor recreational activities. The pulp and wood products
from New York’s lands are used by all of us on a daily basis. Timber harvesting results
in the periodic removal of trees from forest stands according to a prescribed management
plan designed to perpetuate timber production on a sustained basis. Such harvesting
creates openings in the forest canopy which encourages growth of light-loving plant
species, such as raspberry, blackberry, pin cherry, aspen, scarlet elder, and black
cherry as well as a variety of shade tolerant plants and trees. Well-planned timer
management programs result in a variety of tree age classes ranging from young seedlings
and saplings to mature trees. Furthermore, such practices promote the establishment
and development of a diverse plant community which includes intolerant, mid-tolerant
and shade tolerant woody and herbaceous plants.

Research conducted through the AEC on black bear food habits and habitat use in the
central Adirondacks has shown that raspberry abundance is 48 times higher, and pin
cherry production is 37 times higher, on managed private timberlands when compared
with unmanaged public Park land. Although beechnut production was greater on unmanaged
lands within the Park, managed timber stands also produced high numbers of beechnuts,
and greater numbers of juneberries, elderberries, and blackberries. During the spring
and summer bears preferred managed timberlands over unmanaged lands. Bears used managed
and unmanaged lands equally during the fall. Wetland areas and fire succession stands
found on both private and public lands within the Park were also important food production
areas used by bears periodically during the spring, summer, and fall.

The interspersion of relatively large tracks of forested managed and unmanaged land
throughout the Adirondack Park provides for continued production of the wide range
of food resources important to black bears during all seasons of the year. Together
these two forest landscapes assure the continuation of the diversity of habitats necessary
to support a thriving black bear population in the Adirondacks. New York state’s black
bear population in the third largest in the eastern United States.

Activity and Movement

During the warmer months of the year, a black bear leaves its day bed, a shallow depression
on the ground, in late afternoon or at dusk, and may remain active throughout the
night. Feeding or breeding activity may take place during daylight hours as well.

The black bear spend the winter months in a den where it enters into a deep sleep.
Although not a true hibernator, the bear’s body temperature declines 10 degrees F
and their metabolic rate declines 50-60%. During this period of dormancy, a black
bear does not eat, drink, urinate, or defect, and relies upon fat reserves for energy,
losing approzimately15-25 % of its body weight. Photo period (day length) and food
availability rather than temperature or other weather factors appear to cause bears
to enter winter dens. Females tend to den earlier (usually by late November) than
males (mid December). Emergence is in the reverse order, and occurs in late March
and early April. Den sites include cavities within of under rocks, hollow trees, brush
piles, fir and spruce trees, wind-toppled trees, and rarely in open areas of forest
floors that offer no protection other than a blanket of snow.

When traveling on the ground, the black bear often uses the same pathway or trail,
sometimes stepping in the same footprints for years. The normal gait is a deliberate,
slow walk, sometimes punctuated with pauses during which the bear stands on its hind
limbs to sniff the air or perhaps have a better view. Bears bound or gallop when running,
and can attain speeds of 28-32 mph for brief periods. The black bear may wade or wallow
in mud or water, and is a strong swimmer, capable of swimming at least 5 miles. This
mammal climbs trees by pulling itself up with its front legs and it backs down tree
trunks

The black bear is very mobile, often traveling several to many miles in one night.
Evidence of this mobility stems from documented wanderings of translocated individuals.
One male moved 259 miles after its release. Another, captured in the Adirondacks and
released on Tug Hill, returned 56 miles to the point of capture. This ability to move
long distances shows that capture-transfer programs for nuisance bears are futile;
they either become a problem bear in another community, or return to their original
location.

Predators

The black bear has no predators among the wild animals that currently reside in the
Adirondack Park except other black bears. This species is cannibalistic under certain
conditions.

Social Behavior

Social System

Comparatively little is known about the mating system and social organization of the
black bear. This is especially true for the Adirondack population. This species is
thought to be promiscuous, and with the exception of the family unit, is solitary
except when breeding or congregating around landfills or campsites.

Age, sex, season, and population density are important determinants of home range
size. Home ranges overlap; males have larger (100-125 sq. mi) ranges that females
(24-50 sq. mi). North American densities vary from one black bear per 0.9 – 76 sq.
mi.

Communication

Although usually silent, bears vocalize in social contexts and aggressive encounters
with other species (woofs, roars, grunts, moans). Cubs whimper, squeal, and purr.
Combinations of vocal and visual (motor patterns, displays involving ear positions
and facial expressions) signals are prevalent in dominant-subordinate conflicts that
occasionally progress to fighting. Black bears mark trees, biting and clawing trunks
5-7 ft above the ground. On smooth barked trees such as beech, scars from marking
as well as from climbing, are visible for years. The function of tree marking is unknown,
but may be a form of signaling.

Additional References 

Costello, C. 1992. Black bear habitat ecology in the central Adirondacks as related to food abundance
and forest management. M.S. Thesis. State University of New York, College of Environmental
Science and Forestry, Syracuse, 165 pp.

O’Pezio, J. 1984. Unraveling the mysteries of bear denning. The New York State Conservationist,
38(4):23-25.

Sauer, P.R., L. Free, and S.D. Browne. 1969. Movements of tagged black bears in the Adirondacks. New York Fish and Game Journal,
16:205-223.

Simek, S.L. 1995. Impacts of forest land management on black bear populations in the central Adirondacks. M.S. Thesis, State University of New York, College of Environmental Science and Forestry,
Syracuse, 232 pp.

Tietje, W. D., B.O. Pelchat, and R.L. Ruff. 1986. Cannibalism of denned black bears. Journal of Mammalogy, 67:762-766.