Getting the average life-span for wild black bears is very difficult,
but we do know that after 15 years a bear can be considered old.
The 2 oldest known bears from Florida were 18 years old when they died
(one as an apiary nuisance, the other apparently drowned). Both sows
were from the Ocala population. The oldest known male, from the
Apalachicola population, was killed by a vehicle at 15. In zoos, black
bears have been known to live into their 30s. Adult black bears have no predators besides humans
and other bears, but do suffer mortality from other sources:
Cubs: Approximately 25% of all cubs die before they turn one
year old. Natural causes of death include drowning, den cave-ins,
hypothermia due to flooded dens, starvation, falling from trees,
infections from injuries, and predation (by bobcats, coyotes, or other bears
- mainly males). They are also struck by vehicles.
Juveniles: Yearlings have outgrown many threats (cave-ins,
hypothermia, etc.) and enjoy the guidance and protection of their mother
until summer, when they establish their own home range. Inexperience
results in high mortality rates from starvation, especially during poor
mast years, predation by other bears, and vehicle collisions.
About 23% will die before they turn two years old.
Young, independent females establish a home range close to their
mother. Even with this local knowledge, they still suffer from
collisions with vehicles and human conflicts, and predation from other
bears. Starvation, especially in poor mast years, is also a
problem. About 20% die before reaching adulthood (~4 years
old). Juvenile males travel farther in search of a new home range.
The traveling needed to forage and find new den sites in unknown
territory increases these
risks, about 46% of males will die before adulthood.
Adults: Once fully grown, black bears have no predators besides
humans and other bears. Main causes of mortality are old age, vehicle
collisions, starvation, and poaching (Florida has no legal
hunting season). Additional causes include other bears ( intraspecific
fighting and cannibalism), disease, and accidents.
Little information is available
on the diseases and parasites of wild black bears. Research shows
that, while bears host external parasites (ticks and mites) and several
types of internal parasites (helminths, nematodes, trematodes, and acanthocephalams),
they are not believed to cause any significant problems.