Ducks are a common sight on many bodies of water, from small ponds to vast lakes and coastal areas. While they often appear to simply float on the surface, their interaction with water involves a surprising range of behaviors, often involving submerging themselves beneath the surface.
Do All Ducks Dive?
Not all ducks engage with water in the same manner, and their diving capabilities vary significantly. Ducks are broadly categorized into two main groups based on their feeding behavior: dabbling ducks and diving ducks. Dabbling ducks, such as Mallards, primarily feed by tipping their heads and upper bodies into shallow water, with their tails often visible above the surface. They typically forage for aquatic plants, seeds, and small invertebrates found near the water’s surface or in shallow mud. While dabbling ducks can occasionally make short, shallow dives, particularly to avoid predators or access slightly deeper food, they are not adapted for prolonged underwater activity.
In contrast, diving ducks are well-suited for full submersion and actively propel themselves underwater. Species like Canvasbacks, Mergansers, and Scaup have evolved distinct physical characteristics that enable them to pursue food in deeper waters, including aquatic vegetation, mollusks, and fish. Their ability to fully submerge allows them to exploit food sources inaccessible to dabblers.
How Ducks Go Underwater
Diving ducks possess specific anatomical and physiological adaptations that facilitate their underwater movements. Their bodies are more compact and streamlined, which helps reduce drag as they move through water. A distinguishing feature is the position of their legs, which are set farther back on their bodies compared to dabbling ducks, providing enhanced propulsion during underwater swimming. Their large, webbed feet function like powerful flippers, pushing against the water to propel them with speed and precision. Some diving ducks, like Common Mergansers, have also been observed using their wings for additional propulsion while pursuing prey underwater.
Ducks also manage buoyancy to aid in diving. Before submerging, they compress their feathers tightly against their bodies, expelling air trapped within their plumage, which reduces their overall buoyancy. While they cannot breathe underwater, ducks hold their breath during dives. Their respiratory system includes lungs and specialized air sacs that store oxygen, and their bodies have a high tolerance for low oxygen levels. A “diving reflex” triggered by water touching their nostrils slows their heart rate and redirects blood flow to essential organs, conserving oxygen for the duration of the dive.
Why Ducks Dive
Ducks dive for several important behavioral reasons, primarily related to obtaining food and avoiding danger. Foraging is a major motivation, as diving ducks access food sources such as aquatic plants, seeds, invertebrates, and fish found at various depths. Diving allows them to exploit a broader range of food items compared to surface feeders.
Diving also serves as an effective defense mechanism against predators, especially aerial threats like hawks and eagles. By quickly submerging, ducks can evade an attack, often resurfacing some distance away from their initial dive point. The ability to stay underwater for extended periods can exhaust a persistent predator. Diving can also be part of courtship displays, where males perform elaborate underwater maneuvers to attract mates, and sometimes for thermoregulation.