The rutting season is when males challenge each other for superiority and create a social hierarchy. Rarely are there injuries, as they lock antlers together rather than use them as weapons to wound the body.
The actual fighting consists of the moose pushing against each other to see which one will tire first. Moose are the largest of the deer family, and you can tell them apart by their huge palmate antlers; each set is unique. Other deer tend to have the twig style antler.
As you can see in these images, the moose have shed the “velvet” which lines their antlers, leaving them stripped down to the bone. Often these become very dark and stained during the rut as a result of all the fighting and wallowing. Maintaining their size for the rut means that male moose have to eat nearly 10,000 calories a day.
On a cold snowy day, we see five bulls together, two of them locked in combat. During the rut, when the males are fighting each other, the females go into oestrus and the males start to call to them.