Study: urban black bears 'live fast, die young'

September 30, 2008

Black bears that live around urban areas weigh more, get pregnant at a younger age, and are more likely to die violent deaths, according to a study by the Wildlife Conservation Society (WCS).

The study, published in the Fall 2008 issue of the journal Human-Wildlife Conflicts, tracked 12 bears over a 10-year period living in urban areas around Lake Tahoe, Nevada and compared them to 10 "wildland" bears that lived in outlying wild areas. The authors found that bears in urbanized areas weighed an average of 30 percent more than bears in wild areas due to a diet heavily supplemented by garbage. The authors believe that because the bears weigh more they are giving birth at an earlier age – on average when they are between 4-5 years old, as compared to 7-8 years for bears in wild areas. Some urban bears even reproduced as early as 2-3 years of age around Lake Tahoe.

Urban bears also tend to die much younger due mostly to collisions with vehicles, according to the study. All 12 urban bears tracked by the researcher were dead by age 10 due to vehicle collisions, while six of the wildland bears still survived. Bear cubs in urban areas also had dramatically higher mortality rates due mainly to vehicle collisions.

"Urban areas are becoming the ultimate bear traps," said Wildlife Conservation Society researcher Jon Beckmann, the study's lead author. "Because of an abundant food source – namely garbage – bears are being drawn in from backcountry areas into urbanized landscapes where they meet their demise."

The study warns that urbanized areas are functioning as "sinks" for black bear populations, drawing in bears from outlying wild areas, where they ultimately die. As a result, bears are failing to re-colonize outlying wild areas following this shift to urban centers.

The authors believe that without these sinks, populations of black bears in Nevada could increase. Right now, populations in Nevada remain steady due to bears immigrating from neighboring California. The Wildlife Conservation Society is studying the effects of urbanization and sprawl on a variety of wildlife and habitats in North America. WCS continues to work with local authorities to increase the use of bear-proof garbage containers and improve education efforts to reduce human-bear conflicts.

Source: Wildlife Conservation Society

Explore further: Does your smartphone make you less likely to trust others?

Related Stories

Does your smartphone make you less likely to trust others?

January 12, 2017

Imagine you are visiting a new city and get lost on your way to that famous must-see museum. In times of yore – actually just about 10 years ago – you might have had to consult a friendly local to direct you. Today, with ...

Hazardous chemicals discovered in flavored e-cigarette vapor

November 10, 2016

Building on more than 30 years of air quality research in some of the most polluted urban environments on Earth, a team of atmospheric scientists at the Desert Research Institute (DRI) have turned their attention toward the ...

Black bears: Here, gone, and back again

March 29, 2013

A new study from the Wildlife Conservation Society (WCS) and the Nevada Department of Wildlife (NDOW) has pieced together the last 150 years of history for one of the state's most interesting denizens: the black bear.

Vanishing big trees put Australia's urban wildlife in peril

January 13, 2015

Across Australia - and the world - the future of large old trees is bleak and yet large trees support many species such as birds and small mammals, says Mr Darren Le Roux, a PhD student at the ARC Centre of Excellence for ...

Recommended for you

Cooperation helps mammals survive in tough environments

January 24, 2017

Cooperatively breeding mammal species, such as meerkats and naked-mole rats, where non-breeding helpers assist breeding females in raising their offspring, are better able to cope with living in dry areas than related non-cooperative ...

Gaia turns its eyes to asteroid hunting

January 24, 2017

While best known for its surveys of the stars and mapping the Milky Way in three dimensions, ESA's Gaia has many more strings to its bow. Among them, its contribution to our understanding of the asteroids that litter the ...

Your (social media) votes matter

January 24, 2017

When Tim Weninger conducted two large-scale experiments on Reddit - otherwise known as "the front page of the internet" - back in 2014, the goal was to better understand the ripple effects of malicious voting behavior and ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Sophos
not rated yet Sep 30, 2008
"Black bears that live around urban areas weigh more, get pregnant at a younger age, and are more likely to die violent deaths"

WOW just like humans
bobwinners
not rated yet Sep 30, 2008
Gotta be that urban lifestyle!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.