The coyote has been one of the most-studied critters in the Yellowstone ecosystem. Many have been collared, like this character in Lamar Valley. When the wolves were re-introduced, the coyote entered a new era. No longer the top dog in Yellowstone, the coyotes have had to adapt to their new, and more aggressive, neighbors. Before the re-introducion, Yellowstone had packs of coyotes, something that is seldom seen outside the Park. Now the groups are limited mostly to family, but the song dog continues to thrive. It has learned to make the most of its cousin's presence, scavenging the remnants of the wolves kills.