American black bear

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Ursus americanus


Mother black bears are notoriously protective of their cubs, who stay with their mothers for about two years.
Photograph by Norbert Rosing



Black bears are North America's most familiar and common bears. They typically live in forests and are excellent tree climbers, but are also found in mountains and swamps. Despite their name, black bears can be blue-gray or blue-black, brown, cinnamon, or even (very rarely) white.

Black bears are very opportunistic eaters. Most of their diet consists of grasses, roots, berries, and insects. They will also eat fish and mammals—including carrion—and easily develop a taste for human foods and garbage. Bears who become habituated to human food at campsites, cabins, or rural homes can become dangerous and are often killed—thus the frequent reminder: Please don't feed the bears!

Solitary animals, black bears roam large territories, though they do not protect them from other bears. Males might wander a 15- to 80-square-mile (39- to 207-square-kilometer) home range.

When winter arrives, black bears spend the season dormant in their dens, feeding on body fat they have built up by eating ravenously all summer and fall. They make their dens in caves, burrows, brush piles, or other sheltered spots—sometimes even in tree holes high above the ground. Black bears den for various lengths of time governed by the diverse climates in which they live, from Canada to northern Mexico.

Female black bears give birth to two or three blind, helpless cubs in mid-winter and nurse them in the den until spring, when all emerge in search of food. The cubs will stay with their very protective mother for about two years.

Type: Mammal
Diet: Omnivore
Average life span in the wild: 20 years
Size: 5 to 6 ft (1.5 to 1.8 m) long
Weight: 200 to 600 lbs (90 to 270 kg)
Group name: Sleuth or Sloth
Did you know? Black bears are not true hibernators. During their winter dormant period, though, they do not eat, drink, urinate, or defecate, but may wake up if disturbed.

Size relative to a 6-ft (2-m) man:

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A study done on the average weight of Black bears across several regions;

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INTERSPECIFIC CONFLICT:






MACROPREDATION:

"Because there are no records of black bear preying on adult elk in the literature, the following observations of a single adult killing two mature, male elk on the same or successive days at the same spot are worth recording."





"Bear biologist Martin Obbard, at the Ontario Ministry of Natural Resources in Peterborough, Ont., stresses that predatory attacks by black bears are rare. Still, he says, "Bears do kill things. In Chapleau, a male black bear killed a moose cow. That was pretty impressive: he weighed about 340 lb. and the moose was about 800"





"Twenty-three Black Bears (Ursus americanus) were captured, 20 were measured, marked and/or radio collared, in northeastern Labrador, between 1996 and 1997. Bears used sea ice for travel, coastal islands for denning, hunted adult Caribou (Rangifer tarandus), and were the possible cause of Moose (Alces alces) calf mortality. Body sizes were small, median weight of adult females was 48 kg".

"With their big brown cousins gone, black bears moved permanently out onto the now-safe Labrador tundra. The descendants of these pioneering bruins became Veitch's study subjects. He followed them and watched them, from the time they emerged from winter dens throughout the summers of 1989 through 1991. He caught, weighed, collared and released 22 of them. And he learned that these black bears are behaving like brown bears.



When they first awaken in the spring, the bears go after meat. They eat ringed seals, either catching seals frozen out of their escape holes in the ice or scavenging dead ones killed by shifting ice. They hunt caribou and they excavate burrowing rodents, digging up voles or lemmings much as Alaska grizzlies go after ground squirrels".

"Told the game warden about some bear tracks we've been picking up around one of our hog feeders, so they set up a trap to catch him.



The bear also seems to like pork too, as we found this freshly killed hog next to the trap when we caught him, he'd broken the hog's back with one bite...."




INTERACTIONS WITH OTHER PREDATORS:


"Bears will

also occasionally kill wolves as Joslin (1966), and Pimlott et al. (1969) reported in

Ontario, Canada. In both instances, black bears were responsible for the deaths of

individual wolves. According to Joslin (1966), a black bear killed a female wolf

protecting her pups at a den site."



"A black bear recorded scavenging and feeding on a deer killed by a

mountain lion with a motion-triggered camera. Bears regularly steal food

from mountain lions, and mountain lion kills are monitored by biologists to

measure the effects of scavengers on the kill rate of mountain lions".



"Pumas (Puma concolor) and black bears (Ursus americanus)

are large carnivores that may influence scavenger population

dynamics. We used motion-triggered video cameras deployed at deer

carcasses to determine how pumas and black bears affected three

aspects of carrion acquisition by scavengers: presence, total feeding

time, and mean feeding-bout duration. We found that pumas were

unable to limit acquisition of carrion by large carnivores but did limit

aspects of carrion acquisition by both birds and mesocarnivores.

Through their suppression of mesocarnivores and birds, pumas apparently

initiated a cascading pattern and increased carrion acquisition

by small carnivores. In contrast, black bears monopolized carrion

resources and generally had larger limiting effects on carrion

acquisition by all scavengers. Black bears also limited puma feeding

behaviors at puma kills, which may require pumas to compensate

for energetic losses through increasing their kill rates of ungulates.

Our results suggest that pumas provide carrion and selectively influence

species acquiring carrion, while black bears limit carrion availability

to all other scavengers. These results suggest that the effects

of large carnivores on scavengers depend on attributes of both carnivores

and scavengers (including size) and that competition for carcasses

may result in intraguild predation as well as mesocarnivore

release."


Black bear chases juvenile Grizzly, likely as large as if not largerr than itself, from kill (13:25-14:10):

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Brief encounter between black bear and mountain lion:

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An American black bear killed two adult male elk back in 1969 in Yellowstone National Park. These elk were both healthy, although they also shed their antlers before death. The bear's ability to hunt them would have been enhanced/enabled by the deep snow conditions making it difficult for the elk to escape (Barmore & Stradley, 1971).



In 2009 a black bear killed an adult whitetail doe. This doe was not malnourished judging from her bone marrow, and was likely exsanguinated to death (Svboda et al., 2011).




In 1992, a 138 kg male black bear killed an adult female moose. The bone marrow indicated the moose was not dying from starvation. It's thought that the bear attacked while the cow moose was lying down, and eventually killed her by either pulled on her head in an attempt to break her neck, or partially covered its muzzle and suffocated it (Austin et al., 1994).

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American Black Bears Depredate American Alligator Nests in South Florida

Ursus americanus (American Black Bear) and Alligator mississippiensis (American Alligator) are sympatric in areas of Florida. During summer, alligators build nest mounds for eggs on freshwater shores, shallow marshes, and tree islands. Biologists have speculated that bears might prey upon alligator nests because of their opportunistic and generalist diet, though such predation in Florida has not been documented in peer-reviewed literature. Herein, we report 3 photographed events of American Black Bear predation on American Alligator nests in Everglades National Park, Big Cypress National Preserve, and Dinner Island Ranch Wildlife Management Area, FL. During each event, bears dug into alligator nests and consumed egg contents. The predation events varied in duration from 36 minutes to nearly 5 hours. During 1 event, a female bear consumed alligator eggs alongside 2 cubs of the year. Future research might explore the extent and effect of nest predation on American Alligator populations and the benefits to American Black Bears.

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