The moose rut can be a violent affair. Although during most of the winter season, bull moose hang out in - friendly - groups, the rut during late September and early October spells trouble.
I heard this bull moose before I saw it as it walked through the forest, moaning and grunting loudly with every step. The signs of an encounter with a bigger and stronger bull were visible: especially looking at the moose from the front, the right eye had a big swelling over it and several parts of the its antlers were missing.
