Isle Royale was initially habited by caribou, no wolf, no moose. Moose swam to the island in the early 1900's. Hunting and parasites from the moose eliminated the caribou. Around 1950, the first wolf showed up, probably walking across the ice from MN. That started the long running predator prey study by Michigan Tech. The wolf population had a inbreeding problem and the powers to be decided to introduce new genetic material a few years ago. Not sure what is left to study and the predator prey population cycles are very well understood.