When it comes to meals on wheels, the black bears of Yosemite may have figured out that minivans may be vehicles that offer the best prospects for finding something to nibble.
Picture the scene: thousands of visitors camp overnight each year in California’s Yosemite valley, one of the most popular U.S. national parks. Many, if not all, of the hundreds of parked cars contain food or at least a lingering whiff of snacks.
NGS photo by Dick Durrance II
Every year scores of campers report vehicles broken into by perpetually famished bears strong and determined enough to smash windows and pop doors open to get at the food within. Not even regular nocturnal patrols by park rangers seem to deter the ursine rogues.
Knowing that bears select techniques to hunt and gather food in the wild that get the best return for the energy expended, scientists wondered if bears apply a similar strategy to parked vehicles.
“The top choice of vehicle by black bears in Yosemite National Park has been the minivan.”
“For a seven-year period, the top choice of vehicle by black bears in Yosemite National Park has been the minivan,” says a news release by the Journal of Mammalogy, a research journal published by the American Society of Mammalogists.
“The bears seem to base this decision on ‘fuel efficiency’–that is, which vehicle offers the best opportunity of finding a meal. As a result, black bears have shown a strong preference for breaking into minivans over other types of vehicles,” the Journal says.
NGS photo of black bear by David Alan Harvey
An article in the October 2009 issue of the Journal of Mammalogy examines the number of vehicles, by make and model, that black bears broke into from 2001 to 2007 in Yosemite. The research was led by Stewart W. Breck of the U.S. Department of Africulture’s National Wildlife Research Center.
“In all years, minivans had the largest or second largest number of break-ins by bears,” the Journal said. “When the number of break-ins was compared to the numbers of each type of vehicle visiting the park in 2004-2005, only minivans were broken into at a rate higher than expected based on their availability.”
Why do bears prefer minivans?
As humans and wildlife must increasingly coexist in closer proximity, animal populations will make use of resources associated with humans, such as livestock, trash, and pet food, the Journal explained.
“Black bears have been known to raid trash cans, break into houses and cars, and steal food from campers. In nature, black bears are selective in their foraging behavior. That same selectivity may apply when choosing from which vehicle to seek a meal.”
There was a time when visitors in U.S. national parks regularly fed black bears from their cars, as seen in this picture. This is no longer allowed, but bears still associate people and their cars with food.
NGS photo by Andre H. Brown
Reports detailing 908 vehicles broken into by Yosemite black bears between 2001 and 2007 were reviewed. The rates of break-ins for nine categories included: minivan, 26 percent; sport-utility vehicle, 22.5 percent; small car, 17.1 percent; and sedan, 13.7 percent.
The article offers four hypotheses about why Yosemite’s black bears are choosing the minivan:
1) Minivans are more likely to emit food odors, based on the fact that minivans are designed for families with children—who are more likely to spill food and drink in a vehicle.
2) Passengers of minivans are more prone to leave large amounts of food in a vehicle parked overnight, including in coolers ands grocery bags.
3) Minivans may be structurally easier to break into than other types of vehicles. Bears most often gained access to minivans by popping open a rear side window.
4) A few individual bears could be responsible for all the break-ins, and they are displaying a learned behavior for choosing minivans.
A black bear raids a picnic table in the Great Smoky Mountains National park.
NGS photo by George F. Mobley
The black bear (Ursus americanus) is one of the most adaptable of all large carnivores and conflict with humans is a critical and growing management issue throughout its range, the researchers write in their article. “Understanding details of the foraging behavior of carnivores in [human] environments can help reveal specific causes of conflict, leading to better strategies for reducing availability of [human] foods and preventing conflict.”
This work was funded by Yosemite National Park and the USDA’s National Wildlife Research Center.
NGS photo by David Alan Harvey