"So today I had the most amazing wildlife encounter. I was driving a bus full of people on the David Thompson highway in Alberta, Canada and got stopped for an hour due to a motorcycle accident that happened when a biker stopped to see a bear on the side of the road and was hit by another biker. (a lot of road rash and maybe some broken bones but they survived). Turns out the little black bear was in the tree because a huge grizzly bear was at the bottom of the tree trying to get him (or her?). We watched the poor little black bear hang on for dear life and make a number of attempts to get away. I had to leave before the end of this encounter and I can only hope the black bear made out okay although his chances did not look good".
Nature Shock - The Bodiless Bear The fascinating documentary series examining freak occurrences in the natural world continues. This programme looks at a series of brutal attacks on black bears in Yellowstone Park, including the extraordinary case of a severed bear head. As experts examined the seemingly unrelated cases, they found evidence that the killings were the work of the black bear’s more aggressive relative, the grizzly bear. In 1990, whilst hiking through Yellowstone National Park, bear expert Dr David Mattson came across a most hideous and unbelievable sight: the severed head of a black bear. Mattson describes his grisly find as “one of the most macabre things I’ve ever seen”. The case of the bodiless bear, and three subsequent bear slayings, would go on to shed new light on what scientists understand about bears and their habitat. All the evidence indicated that the bear without a body had fallen victim to a larger, more savage predator that had killed it for food. But biologists only began to understand the case when a second black bear was found dead on an open stretch of land. This bear had been brutally attacked and its penis had been ripped off. Judging from puncture marks on the corpse, it was clear that only one predator in Yellowstone could have been responsible. “If you look at the preponderance of evidence, it leads us to conclude that he had been killed and eaten by a grizzly bear,” says biologist Dr Charles Schwartz. Grizzlies are almost twice the size of their more placid black bear cousins. They are among the most fearsome predators in North America, standing at a height of eight feet and capable of running at up to 30mph. However, whilst it was known that bears sometimes turn on their own kind, there had never been a documented case of grizzlies killing black bears in Yellowstone. The bears’ habitat provided a possible explanation. Black bears are primarily forest dwellers, whilst grizzlies rule the open spaces. However, both species sometimes overlap in the trees when foraging for food. The first killing could have been an opportunistic attack by a grizzly; the second was a clear case of a black bear straying onto grizzly territory. The third incident, however, was more surprising. A team of researchers monitoring bears tagged with radio transmitters came across the dismembered body of a black bear in the forest. Body parts were strewn about a clearing and the bear’s skin had been pulled inside out. This was the first case of a grizzly attack deep inside black bear territory. After close investigation, the team concluded that the beasts had been foraging in preparation for winter hibernation when they encountered each other. “The bear spends most of its active period in the fall searching for and consuming foods,” explains Schwartz. The grizzly was looking for fattening pine cones when it decided to feast on its opponent instead. The fourth victim was found in a scene eerily similar to the last – but with the crucial difference that it was killed at the end of winter. Grizzlies awake from hibernation before black bears, and it is believed that one such creature – driven by hunger – detected its sleeping cousin and took the opportunity to strike while it was in its den. The research team was even able to track down the grizzly responsible from a ripped-off claw that it left at the scene. These four shocking cases have provided biologists with concrete evidence of grizzly predation on black bears for the first time, and offer striking insight into the behaviour of bears. “No two bears are alike,” affirms Dr Mattson. “I’ve known some bears that I would consider to be well adjusted and... some bears that probably could be called psychotic.” The bear slayings of Yellowstone Park have helped scientists to understand more about how these remarkable creatures co-exist in the wild.
The survival rate estimate for cubs weaned to one year was 0.45 (95% CI = 0.33, n = 20). Mortality sources for cubs were largely unknown, but we did document instances of suspected grizzly bear predation on 2 denned female black bears with cubs. Among adults through June 1998, we documented mortality only among males. Two adult males died of unknown causes, 1 of which was observed being eaten by an adult black bear. Another male was killed by a grizzly bear and another was harvested by a hunter. The mean annual survival rate for adult males was 0.86 (95% CI = 0.25, n = 15). The mean annual survival rate in 1997 was lower than 1995 (Z = 1.97, P = 0.02). alaska.fws.gov/nwr/yukonflats/pdf/black_bear_monitoring_ursus.pdf