Webbed Feet Are an Evolutionary Hit

This audio story is brought to you by BirdNote, a partner of The National Audubon Society. BirdNote episodes air daily on public radio stations nationwide.

Transcript: 

This is BirdNote.

Webbed feet are ideal for birds that swim, on the water’s surface or under. In fact, they’re such a nifty adaptation that they evolved, independently, in several bird groups.
Ducks and geese have them, as do gulls, cormorants, loons, pelicans, penguins, puffins and boobies.

Experiments suggest that a triangular webbed foot is beautifully designed to propel a bird, or other creature, through the water.

The toes and webs spread out as the bird pushes its foot backward. Then as the bird pulls its foot forward, the toes fold together, to minimize resistance. And many birds have mastered a stroke that any human swimmer might envy. A bird may lift its foot away from its body on the forward stroke, actually giving itself a little extra lift and speed.

Four hundred different species of birds have webbed feet. And a parallel adaptation shows up in other creatures that spend time in the water—like otters, frogs and salamanders.

It’s clear that webbed feet have been a big evolutionary hit. Regardless of who’s wearing them.

For BirdNote, I’m Michael Stein.

Today’s show brought to you by the Bobolink Foundation.

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Credits: 

Written by Bob Sundstrom

Producer: John Kessler

Executive Producer: Sallie Bodie

Editor: Ashley Ahearn

Associate Producer: Ellen Blackstone

Assistant Producer: Mark Bramhill

Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Gadwalls, Canada Geese, and Mallard recorded by T. Johnson.

BirdNote’s theme was composed and played by Nancy Rumbel and John Kessler.

© 2020 BirdNote   March 2020   Narrator: Michael Stein
 
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