Pelicans dive into the water to catch fish. But here’s what most people don’t realize: only two of the world’s eight pelican species actually do this. The Brown Pelican and the Peruvian Pelican are the only ones that plunge-dive from the air. The other six species feed while floating on the surface, dipping their bills underwater to scoop up prey. That dramatic, headfirst crash into the ocean is a specialized hunting technique that requires a remarkable set of physical adaptations to pull off.
How the Dive Works
Brown Pelicans hunt by flying over the water, scanning for schools of fish near the surface. When they spot prey, they fold their wings and plunge headfirst from height, using the force of impact to stun small fish before scooping them up in their expandable throat pouch. The dive resembles a maneuver fighter pilots call a Split-S turn: the bird rolls and pitches downward in a rapid, controlled arc rather than simply dropping straight down.
Once underwater, the pelican’s throat pouch balloons open to trap both fish and a large volume of water. The pouch tissue can stretch 200% to 300% in one direction, giving it an enormous capacity. But the pelican doesn’t swallow anything underwater. Instead, it bobs back to the surface, tips its bill downward to drain the water out, and then tilts its head back to swallow the fish whole.
Why Most Pelicans Don’t Dive
The six non-diving pelican species, including the American White Pelican and the Great White Pelican, are what biologists call tip-up foragers. They float on the water and dip their bills below the surface, scooping fish into their pouches without ever submerging their bodies. They can only reach as deep as their neck, head, and bill can extend. Some species feed cooperatively, herding fish into shallow water in groups before scooping them up. Others follow diving birds like cormorants, waiting to grab prey that gets pushed toward the surface.
Evolutionary analysis suggests that surface feeding is the ancestral method for all pelicans, and plunge diving evolved only once within the family. Brown and Peruvian Pelicans are closely related, and their shared diving ability appears to be a specialized adaptation rather than the default. Notably, Brown Pelicans can still feed from the surface the same way other pelican species do. Plunge diving is an additional tool in their repertoire, not a replacement.
Built-In Protection for High-Speed Impact
Hitting the water at high speed, bill-first, dozens of times a day would be punishing without some serious physical safeguards. Pelicans have several.
- Subcutaneous air sacs: Pelicans have networks of air-filled pockets beneath their skin that extend throughout the body, even into the wings. These sacs likely cushion internal organs during impact and help the bird adjust its buoyancy so it can resurface quickly after a dive.
- A third eyelid: A translucent membrane called the nictitating membrane slides across each eye just before the pelican hits the water. This protects the eyes from the force of impact while still allowing some visibility underwater.
- Body rotation: Pelicans twist their bodies during the dive so they enter the water at a precise angle. This rotation, combined with tucking the wings tightly against the body, reduces the surface area that takes the hit and helps the bird slice through the water rather than slapping against it.
Success Rates Vary With Experience
Plunge diving looks dramatic, but it doesn’t work most of the time. Adult Brown Pelicans successfully catch fish on about 14% of their dives. That’s roughly one in seven attempts. And adults are the most skilled divers in the population.
Younger birds fare much worse. Subadults succeed about 12% of the time, juveniles about 8%, and first-year birds manage to catch something on only 3.5% of dives. That steep learning curve means young pelicans need to dive far more frequently just to eat enough, and it helps explain why pelicans spend so much of their day hunting. The technique requires precise timing, accurate depth judgment, and the ability to read fish movements from altitude. These are skills that improve significantly with practice over the first few years of life.
Why Diving Gives Them an Edge
Surface-feeding pelicans are limited to fish swimming within neck’s reach of the surface. Plunge diving opens up a much larger portion of the water column. The momentum from a high-altitude dive carries the pelican well below the surface, giving it access to fish that surface feeders simply can’t reach. The impact itself stuns nearby fish, making them easier to capture in the fraction of a second before they scatter.
This feeding strategy also lets Brown Pelicans hunt in open ocean waters where surface-feeding techniques would be far less effective. Schools of sardines, anchovies, and other small fish often swim several feet below the surface, well out of range for a floating pelican but perfectly reachable for one diving from 20 or 30 feet in the air. The trade-off is physical wear on the body and a low success rate per dive, but the ability to access deeper, denser schools of fish more than compensates.