Moose displays bloody antlers, prepares for the rut. Taken this past Sunay at Brainard Lake in Arapaho National Forest, Colorado. This monstrous bull moose has begun shedding the velvet that covers its antlers. The blood comes from the blood vessel system that forms the skin covering and grows the antlers. The shedding of the velvet is a precursor to the rut when this male and others nearby will use their massive antlers to battle for the right to mate area females.