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

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, 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: Under threat: Kenya's iconic Nairobi national park

add to favorites email to friend print save as pdf

Related Stories

Water problems lead to riots, deaths in South Africa

Jul 19, 2014

Three babies who died from drinking tap water contaminated by sewage have become a tragic symbol of South Africa's struggle to cope with a flood of people into cities designed under apartheid to cater to ...

21,000 species at risk of extinction

Jul 02, 2013

A freshwater shrimp, an island-dwelling lizard and a pupfish from Arizona have been declared extinct, while nearly 21,000 species are at risk of dying out, an updated "Red List" showed.

Black bears: Here, gone, and back again

Mar 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 ...

Rice launches sweeping Energy and Environment Initiative

Sep 20, 2012

Rice University today announced the Energy and Environment Initiative (E2I), a sweeping plan to support interdisciplinary research that will draw experts from every corner of the university to work with Houston's ...

Recommended for you

Evolution: The genetic connivances of digits and genitals

15 hours ago

During the development of mammals, the growth and organization of digits are orchestrated by Hox genes, which are activated very early in precise regions of the embryo. These "architect genes" are themselves regulated by ...

Study: Volunteering can help save wildlife

16 hours ago

Participation of non-scientists as volunteers in conservation can play a significant role in saving wildlife, finds a new scientific research led by Duke University, USA, in collaboration with Wildlife Conservation ...

User comments : 2

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.