Life Expectancy and Mortality

What's In an Age?

Unlike most animals, we can tell exactly how old bears are. Bears can be aged by removing and sectioning a small premolar tooth near their canine teeth. Just like a tree has growth rings for each year of life, rings show up in the cross section of the tooth. Because bears den each year, there is a period of time where lack of food creates ring. Over the years, enamel coats each ring so that when you look at a section of bear tooth under a scope, you see a ring for each year the bear has been alive.

Bear tooth

While we can tell the age of individual bears, determining the average life-span for wild black bears is very difficult. Many bear die in the wild that are not examined and aged by biologists. We can only report on the ages of bears we have documented over the years.

The 2 oldest known bears from Florida were 20 years old (killed in 1985 during a legal bear hunt held on Apalachicola Wildlife Management Area) and 19 years old (captured in 2004 as part of a University of Kentucky Glades/Highland Bear Population Study). Both bears were females. The oldest known male, from the Ocala population, was killed by a vehicle at age 16. In August 2013, the oldest known wild black bear died in Minnesota of natural causes at the age of 39 years old.  She was actually the oldest bear, of any species, in the world.

In captivity, black bears have been known to live into their 30's. Because adult black bears have no predators aside humans and other bears, they tend to live longer than most other wild animals.

In Florida, the most frequent known cause of death for black bears are collisions with vehicles. In an average year, over 130 bears are killed on roads in Florida.

Life Expectancy and Mortality:

Cubs: Approximately 25-50% of all cubs die before they are one year old. Natural causes of death include drowning, den cave-ins, hypothermia due to flooded dens, starvation, or infections from injuries.

Two of the biggest threats are other bears (who see the cubs as an easy meal) and being hit by vehicles.

Juveniles: Yearlings will establish their own home range once they leave from their mother. Yearlings are susceptible to high mortality rates as a result of starvation, predation by other bears, and vehicle collisions. About a quarter will die before they turn two years old.

Young, independent females usually establish a home range close to their mother. About 20% die before reaching adulthood (about 4 years old).

Juvenile males travel farther in search of a new home range. The traveling needed to forage and find mates in new areas increases mortality risks, and approximately 46% of males will die before reaching adulthood.

The primary known cause of death for Florida black bears are vehicle collisions. Bears of all ages and sizes are susceptible to dying in a crash.

Adults: Once fully grown, black bears have no predators besides humans and other bears. Main causes of mortality are vehicle collisions, starvation, and poaching.

A young adult lies dead on the side of a Florida road. A circular bullet hole in the top of this skull indicates the cause of death.

Hunting:
FWC initiated its first regulated hunting season for bears in 1936.  After population assessments indicated a decline in bear numbers, bear hunting was closed throughout most of Florida in 1971.  Apalachicola National Forest, Osceola National Forest, and Baker and Columbia counties maintained hunting seasons for bears until 1994.  Between 1981 and 1994, an average of 46 bears were killed each year during the legal bear hunting season.  View a timeline that includes hunting regulations and other state management activities regarding the Florida black bear Adobe PDF.

Disease and Parasites:
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 health problems to bears. Bears have been documented to carry mange, however, it is not prevalent or believed to be a significant cause of mortality.



FWC Facts:
The mean breeding period (rut) of white-tailed deer in Florida can vary as much as seven months from one part of the state to another.

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