Hunters are large, and heavily armored units, with Fuel Rod Guns molded into the armor around their right arms, and huge metallic shields that double as a melee weapons on their left.

In Halo 1, a Hunter could be killed by a single sniper or pistol shot to the vulnerable orange fleshy areas that were easy to hit when Hunters were relaxed and standing at their full height, or when their backs were exposed after a melee strike. Word is they will be harder to deal with in Halo 2.

Hunters always travel in pairs.

The Halo 2 manual indicates Hunters are actually composed of more than one creature living inside the armor forming a hive organism.