Monitoring certain areas of Voyageurs National Park found that snowmobiles displaced wolves:

"Our observations indicate that wolf activity in restricted use areas is generally absent during the same interval in which snowmobile incursions are recorded... wolves tend to avoid snowmobile activity in restricted use areas." (p.10)

These results prompted snowmobile closures to protect wolves:

"Information in this report does not prove harm to wolves [emphasis NPS'], but the fact that wolves consistently avoid snowmobiles indicates it is prudent for the NPS to close some important wolf foraging areas to winter use until a better understanding of wolf/snowmobile interactions can be determined." (p.12)