[MarkL]

I'm not sure why this is such a big suprise, and I've wondered about it in the past...

It's long been known that long, smooth surfaces cause additional drag in laminar fluid flow.

That's why golfballs have the dimples. The balls fly farther than smooth ones.

Mark

[yatros from flatwater]

Given the relative viscosity of the two fluids, a whale compares to a fairly fast moving aircraft. Penguins "fly" on pretty stubby wings, as do supersonic aircraft.

FYI, 1,519 10E-6 (m2/s) is the kinematic viscosity of water at 5 degC, compared to 17.2 10E-6 (m2/s) for air at 1 bar and 40 degC, courtesy of www.engineeringtoolbox.com.

I'm not an aeronautical engineer, so I can't tell you quickly what T/P conditions prevail at various Mach levels and altitudes at a leading edge. Apply a 25 fold velocity difference, though, and whales begin to look like jets, operating in similar viscosities.