Seagulls, part of the family Laridae, are common across coastal regions and inland, having successfully adapted to varied environments. They are frequently associated with marine and aquatic life, spending significant time near or on water. Their success is linked to specialized physical traits that allow them to exploit both land and water resources.
The Structure of a Seagull’s Foot
Seagulls do have webbed feet. Their foot structure is classified as palmate, where a thin membrane of skin connects the three forward-facing toes. This tissue joins the second, third, and fourth digits, creating a broad, paddle-like surface. The first digit, a small rear toe known as the hallux, is typically vestigial and remains free from the webbing. This anatomical feature is characteristic of many water-associated birds. The webbing forms during embryonic development when the tissue between the toes does not undergo programmed cell death.
How Webbed Feet Aid Movement
This specialized foot structure provides a mechanical advantage, particularly for locomotion in water. The webbing dramatically increases the foot’s surface area, allowing it to act like an efficient oar for propulsion when swimming. As the gull pushes back against the water, the expanded web creates maximum resistance, driving the bird forward. When the foot is recovered for the next stroke, the toes come together, minimizing drag. The large, flat surface also helps distribute the seagull’s weight across soft substrates like mud or wet sand. This distribution prevents the bird from sinking deeply, enabling easier movement and foraging in tidal flats.
Other Notable Avian Adaptations
Beyond webbed feet, gulls possess physiological adaptations that allow them to thrive in saline environments. A pair of supraorbital glands, often called salt glands, are situated above the bird’s eyes. These glands function as an auxiliary excretory system, filtering excess salt ions from the bloodstream. This filtering is necessary when consuming saltwater or highly saline prey. The concentrated salty solution is then expelled through the nostrils, allowing the gull to maintain its internal electrolyte balance. Gulls also maintain plumage integrity using the uropygial gland, or preen gland, located at the base of the tail. This gland secretes an oil that the bird spreads over its feathers during preening, conditioning the plumage and providing a waterproof barrier.