As any other adults, they are not burned by the destructive effects of the sunlight. They have darker coloration, bigger size, red eyes and have a double Dumahim symbol on their backs. They are the most common enemy type found in the game.
Adult Dumahim have a weapon attached to their right arm in an attempt to preserve their memories of being experts in weapon combat before they lost their minds. Unlike their fledglings counterparts, they do not use their tongues to attack their prey.[1][Soul Reaver]
The Dumahim at Dark Chronicle (by Ardeth Silvereni).
