Griz postholing, Bob Marshall complex.
A few weeks ago on Philip’s blog a comment-er admonished Mr. Werner for leaving food in his car while it was parked in the mountains of New England, contending that by doing so he was tempting the area black bears into becoming habituated to breaking into cars for food. I thought this suggestion ridiculous, and said so, but ever since have been pondering the significant regional variations in bear behavior found across North America, something that has proven to be a worthwhile pursuit. I went in with two questions: why have the bears in Yosemite and the Sierra been so problematic for so long, and why have the bears in Yellowstone never developed similar habits?
For me Yellowstone is the more curious question. The bears there, both Grizzly and Black, were fed in an organized fashion out of cars, in campgrounds, and in dumps for close to a century, from shortly after the parks creation in 1872 to the final closure of the dumps in the late 1960s. Reports suggest that injuries from bears were quite common during this period, but fatalities were notably rare (5 of the 7 reported deaths have occurred after 1970). There are lurid accounts from bears breaking into cabins during the winter and early spring, mostly from very early in the 20th century, but no reports I’ve been able to unearth of a bear breaking into a car, ever. The Grizzly population hovered around 250-300 up to the dump closure, at which point it dipped, likely quite drastically, due to the presumably substantial number of bears the NPS was obliged to kill due to continued habituated food-seeking behavior. A full account of this period has yet to be published. After this purge, the Grizzly population has rebounded and is currently well over 800, though this growth is mostly due to more bears living sustainably in the parts of the ecosystem outside the park, places they were previously likely to be shot due to predating on livestock and things of that nature.
My thesis here is that aggressive treatment on the part of the Park Service prevented what could have been a serious rash of food-habituated bears being ever more invasive, as well as teaching their cubs to do the same.
Black bears have been a problem in the greater Yosemite area for at least as long as Yosemite, and in the early 20th century were fed garbage for entertainment in a very similar fashion. I’m unclear on when Yosemite bears began to break into cars for food, but my sense is that it was fairly recently (last 30 years?). The late 90s seemed to be the apotheosis of this, with close to a million dollars of damage done to various cars. Aggressive education and lots of metal food lockers has brought the damage figure down exponentially since, though the number of human-bear incidents and the number of bears hit by cars continues to be high. Interestingly, the number of black bears in Yosemite National Park is similar to the number of Grizzlies in Yellowstone (just the park), with the former being a fair bit smaller.
My thesis here is that the density of human traffic in Yosemite valley combined with the proximity of major population centers explains why bear habituation continues to be such a durable problem. Yosemite gets a bit more visitors than Yellowstone (3.8 versus 3.5 million in 2014), but I would suppose that the average Yosemite visitor is more likely to be a sloppy car camper, and thus more likely to feed bears whether by accident or on purpose.
Looking at other bear and human dense areas such as Great Smoky Mountain NP (10 million visits in 2014, 1500 Black bears) makes Yosemite seem all the more exceptional. While bears going after the food of backpackers and picnickers has been an issue in the Smoky Mountains, I cannot find any accounts of them breaking into cars. I’m left to assume that the circumstances in Yosemite were and remain unique, and that a combination of high and uneducated human traffic and perhaps a reluctance of the NPS to kill too many bears has allowed the problem to persist.
If anyone has further resources on this question, to which they could point me, I’d be thankful.
(Yellowstone has a great bibliography of articles concerning bears, which makes for enjoyable reading.)