Male Dobsonflies can be identified by the long, fleshy mandibles that can be nearly half the length of their bodies. Females have much shorter ones. The large wings cover most of the abdomen surface when viewed from the above since they fold the wings over the body instead of splaying them out like butterflies might.
Dobsonflies begin life as aquatic larvae before graduating into an airborne insect. The larvae live underwater, feeding on tadpoles, small fish and other young aquatic larvae from other species (like dragonfly naiads and stonefly hellgrammites). Larvae look like underwater centipedes early in life, and adults keep watch over them from a nearby area above the water. Larvae can bite so handling them should be avoided though that does not stop anglers (fishermen and women) from using them as live bait.
Adults are primarily nocturnal (night dwellers) and are naturally drawn to light sources at night. They do not eat. Instead, they spend their days bringing forth the next generation of Dobsonflies.