To make it easier to catch fish. The gular pouch, popularly called the crop, allows the pelican to catch larger prey without them escaping – which is common among birds that hold food with their beak. “That way, they spend just one hour a day looking for food, which represents an advantage from an evolutionary point of view”, explains Maurício Vecchi, from the Department of Ecology at Uerj.
The structure, an extension of the jaw tissue, is extremely elastic and can hold up to 13 liters – making it almost the size of the bird itself. Most of that volume, however, is water, which needs to be expelled through the mandibles. Only then is the fish (which can weigh up to 2 kg) swallowed.
Other birds, such as ibis and flamingos, also have the crop, but the size is not even comparable to those of the Pelecanidae family. In Brazil, the only representative of the family is the pelicanopardo, found in the Amazon basin. The fish can stay alive for a long time in the crop. But the pelican usually swallows it within seconds of catching it.
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