Webbed foot

A foot whose toes are joined by a membrane of skin. The membrane increases the surface area that pushes against water during swimming.

Propulsion: The production of force that moves an organism or object through a medium. A webbed foot generates forward thrust by pushing water backward.
Duck: A waterbird with a broad bill and, in most species, webbed feet. Ducks use their webbed feet to paddle through water.
Foot: A limb structure used for support and movement in many land vertebrates. A webbed foot is a specialized form of the broader foot structure.
Lobed foot: A foot with separate lobes along its toes rather than a continuous membrane joining them. Lobes spread during swimming but do not form the continuous web seen here.
Drag: A force that opposes motion through a fluid or gas. Spreading the toes increases resistance against water during the power stroke.
Platypus: A semiaquatic egg-laying mammal native to eastern Australia. Its forefeet are broadly webbed and help propel it underwater.
Digit: A finger or toe at the end of a limb in vertebrates. Webbing connects the digits that would otherwise move more independently.
Pectinate foot: A foot whose toes bear comb-like fringes that increase their area in water. Fringed toes provide a different paddle structure from a connecting membrane.
Stroke (swimming): A coordinated movement of the limbs or body that propels a swimmer through water. The foot's effectiveness depends on how it sweeps through water and recovers.
Frog: A tailless amphibian with powerful hind limbs, often adapted for jumping or swimming. Many aquatic frogs have webbed hind feet that aid swimming.

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