Why do pelicans have pouches? The pouch is used to catch fish. They use their pouch like fishing nets to scoop the fish into their pouch bills. In fact, pelicans are often accused of giving competition to fishermen, because of their fondness for fish. That is not true though, for they mainly thrive on rough fishes, like carps, which humans do not eat. The pouch also helps to keep the bird cool during warm weather. While basking in the sun, pelicans open their bills and flap the pouch to cool off.