The pelican is a large and instantly recognizable water bird, distinguished globally by its massive bill and the unique skin pouch hanging beneath it. Found in both marine and freshwater environments across the world, this avian species is an expert fish-eater. Pelicans belong to a family of eight species, all of which rely on specialized anatomical features and complex behaviors to secure their aquatic prey. Their spectacular method of foraging, which involves either a dramatic dive from the sky or a coordinated hunt on the water’s surface, makes them fascinating predators.
The Anatomy of the Catch: The Gular Pouch
The most defining feature of the pelican’s head is the gular pouch, a highly elastic, featherless membrane of skin attached to the lower mandible. This pouch is not a storage unit for carrying food back to the nest, but rather a flexible, built-in fishing net used for the momentary capture of prey. The lower jawbones, or rami, are slender and flexible, allowing them to bow outwards when the bill is opened widely during a scoop.
This unique anatomical structure allows the pouch to expand dramatically, holding up to three gallons of water and fish at one time. This capacity is approximately three times greater than the volume of the bird’s stomach, highlighting its function as a temporary collection basket. The bill itself features a downcurved hook at the tip of the upper mandible, which helps to secure slippery fish once they are captured.
The pouch is also rich in blood vessels, serving a secondary, non-feeding purpose in thermoregulation. On warm days, the pelican can flutter the pouch, a process called gular fluttering, which increases air flow over the membrane to release excess body heat. Furthermore, in species like the Brown Pelican, the pouch’s sudden expansion upon impact with the water acts like a parachute, helping to slow the bird’s momentum during high-speed dives.
Diverse Feeding Strategies: Plunge Diving vs. Surface Scooping
Pelicans employ two distinct primary methods for catching fish, determined largely by the species and its habitat. The iconic and dramatic approach is the plunge dive, a technique primarily used by the Brown Pelican and the Peruvian Pelican. These birds spot schools of fish from heights of up to 65 feet, fold their wings back, and plummet into the water at steep angles, sometimes reaching speeds of 40 miles per hour.
To withstand the violent impact, the Brown Pelican has several physical adaptations, including a network of subcutaneous air sacs beneath the skin of its chest. These air sacs inflate just before impact, acting like an airbag to cushion the bird’s body and internal organs. The bird also performs a split-second maneuver just before striking the surface, often twisting its body to the left to protect the trachea and esophagus. Upon hitting the water, the bill opens and the pouch expands, scooping up the prey and a large volume of water.
In contrast, most other pelican species, such as the American White Pelican, use a less dramatic, surface-based feeding method. These birds typically hunt while swimming, dipping their pouched bills into the water to scoop up fish near the surface. They are tip-up foragers, meaning they do not submerge their bodies or dive from the air, and can only reach prey within about three feet of the surface. Foraging may occur by sight during the day or by touch at night, with the sensitive bill detecting fish in murky water.
Processing the Prey: Draining and Swallowing
Once the pouch is filled with fish and up to three gallons of water, the pelican must efficiently process the catch before swallowing. The pouch is not built to hold large amounts of water for long, so the immediate next step is to drain the excess liquid. The bird does this by snapping its bill shut, trapping the fish, and then tilting its head forward and down.
This head-tilting action causes the water to pour out of the corners of the bill, while the flexible pouch contracts to force the water out, effectively acting as a living colander. Only after the water is mostly expelled does the pelican prepare to swallow the prey. The fish is maneuvered within the bill so that it is oriented head-first down the throat.
To complete the ingestion, the pelican lifts its head with a quick, upward jerk, using gravity and muscular contractions to slide the fish down its esophagus whole. Pelicans do not chew their food, as birds lack teeth, and they must be able to swallow the fish in one motion. This process is essential because the bird cannot take flight with a pouch full of heavy water, which is why the draining phase happens immediately after capture.
Social Feeding and Primary Diet
Many pelican species are highly gregarious and frequently engage in cooperative hunting, a behavior that increases their overall feeding efficiency. Species like the American White Pelican often work together in groups, sometimes forming a line or a semi-circle on the water. By swimming side-by-side and synchronously dipping their bills, they actively drive schools of fish toward shallow water or herd them into a tight cluster.
This coordinated effort allows the group to corral the prey, making it easier for each individual to scoop up a meal with minimal effort. The pelican’s diet is overwhelmingly composed of fish, which typically includes small to medium-sized species such as mullet, anchovies, and menhaden. They generally prefer fish that are small enough to be swallowed whole, usually between six and twelve inches in length.
Pelicans are also opportunistic feeders and will occasionally consume other aquatic life, depending on availability. Their diet can sometimes include crustaceans, amphibians, and even small turtles. In rare instances, when food is scarce, some species have been observed preying on other birds, although fish remains their primary food source.