Changes

==Description==

==Description==

Penguins are bulky birds in relation to their size.  Depending on the species, they are between 16 and 48 inches in length.  When standing, they have a fully-erect posture; when moving about, they either walk in a comically-awkward gait or they "toboggan", i.e. they slide on their bellies when on the ice, using feet and wings to push them along.  While at sea, however, penguins use their wings to move about effortlessly, swimming in excess of twenty knots.

Depending on the species, penguins are between 16 and 46 inches in length.  The largest is the emperor penguin (''Aptenodytes forsteri''), which stands close to four feet tall and weighs in at nearly 90 pounds; the smallest is the little penguin (''Eudyptula minor'') at sixteen inches and two pounds.  When standing, penguins have a fully-erect posture and tend to move about in a comically-awkward gait, or they "toboggan", i.e. they slide on their bellies when on the ice, using feet and wings to push themselves along.   

 

The body is streamlined and tapered at both ends, with the feet acting as rudders.  The wings are nearly-fused at the wrists and elbows, and the bones flattened, giving the wings a paddle-like shape.  Despite being flightless, penguins still have a well-defined keel sternum and powerful wing muscles, enabling the birds to move about in the water effortlessly, cruising at ten knots, yet capable of bursts in excess of twenty knots.

 

 

===Phylogeny===

===Phylogeny===