HELENA - A video posted on the Web site of the U.S. Geological Survey captures remarkable interaction between a wolf and a family of 3 grizzly bears in Montana's Glacier National Park.

The wolf draws close to the cubs, only to be chased away by the youngsters and, more seriously, by their mother. But the wolf is not deterred, returning repeatedly for another run at the cubs in what looks like a tease.

The video was shot last summer for grizzly bear research at the park. The USGS announced Tuesday that the footage was available for viewing on the agency's Web site.