The Northwest Territories(Canada) Caribou herd has contracted from an "army" of 161,000 animals to just 31,000 strong today............Despite this, Queens College researchers have determined that the feeding habits of these animals help offset the increased mass of the arctic grasses(caused by the increased global warming temperatures)...............The Caribou chew down the arctic grasses and thus reduce the mass of the plants and thus their heat trapping potential...................Read this intersting article below by clicking on the link provided

Phys.org:

Caribou the missing piece of arctic warming puzzle

click on this link to read the full story
http://phys.org/news/2013-05-caribou-piece-arctic-puzzle.html