As with their closest relatives, the Pelicans, Cormorants also have a beak-pouch, or gular sac, though it is not as extensive or obvious, only going about halfway up the mandible, as opposed to the full length in the Pelicans.

Sometimes it will be distended during calling or display, Here, a Pied Cormorant is showing it very well distended. About as prominent as you will see in a Cormorant.

They don't rely on it as much as the Pelicans for catching & draining their prey, though like them, it does facilitate the feeding of the young, making it easier for them to get down into the parent's crop to extract the food.

All others in the order Pelecaniformes share this feature, along with totipalmate feet, with all four toes being webbed.