Not aggressive by nature, many perceive moose as harmless- even friendly- woodland creatures. There is an adjustment for exclusive deer hunters when they decide to hunt moose. Aside from the higher caliber weaponry and need to explore more northern reaches to hunt moose, understanding them as the hunted is much more complex.
Plenty of casual observers mistake moose temperament for that similar to that of the dodgy and skittish whitetail deer. The fact is, aside from being even-toed hooved animals, antlered males and sharing much of the same habitat, the moose and whitetail deer have absolutely nothing in common. They attack many more people annually than deer and even more than bears.
The gap in behavior is tremendous between the two species. For starters, whereas a deer will buck off with the understanding its fawn will be close behind at the slightest threat, a moose has a much different demeanor with such a scenario. When threatened, especially with calf, moose are much more likely to attack. In this regard their demeanor is much more similar to that of a bear than a deer.
Aside from being more protective of their young, moose take a more aggressive nature in the months of March and April. This is because food is scarce during these months and, not unlike humans, moose are especially grumpy and aggressive. And knowing to pay close mind when hunting the largest member of the deer family can arm you with knowledge to avoid being charged and possibly killed.
Understanding basic differences between deer and moose lie in understanding the basic differences in their behavior. For starters, knowing they tend to show much more aggression than deer are ever capable of protect your safety and better prepare you for compromising situations. But knowing they are exclusively herbivores will give you some assurance you wont ever wind up on their menu.