If Nature had intended us to fly, she would have given us fingers

You cannot learn to fly by flying. First you must learn to walk, then to run, then to climb, then dance.
- Friedrich Nietzsche

Nietzsche should perhaps have added swimming to that list - but then again, there are more things on earth than are dreamt of by philosophers, so on to this week's list.

Here is a lecture on the evolution of flight by John Maynard Smith. Maynard Smith started off as an aeronautical engineer designing planes during World War II, but is much more famous for his work in using game theory to understand animal behaviour. This lecture is especially fun because Maynard Smith applies basic aerodynamics to make a pretty deep observation about the evolution of flight in animals. Flying, as far as we know, independently evolved four times: among insects, pterosaurs, birds and bats. Maynard Smith shows how a tail is necessary for flight stability, and how as the ability to fly develops, all four groups seem to have moved to shorter tails and more complicated flight controls for better maneouvrability. I was delighted to look at the fossil of the bat Icaronycteris this week, and see how bats had long tails too when they evolved during the Eocene !

In comparison, animals seem to have independently evolved aquatic lifestyles many more times. My list so far has ichthyosaurs, plesiosaurs, mosasaurs, whales & dolphins, seals (?), elephants ... and I'm surely missing some (Can you think of any more ? Write in and let me know !) I wonder if aerodynamics also constrains the evolution of swimming animals. Anyway, what we do know from this past week are more details of the path that whales took, about all the walking and running and giving-birth-head-first that they did before taking to the water like a .. err ... like a fish: here's the tale of the good mother whale. Or an awful limerick - take your pick.

Whale was once a land-lubber
Who would wallow in pools and slumber.
Slowly, his hands became fins
So his legs he traded in
For some flukes and a coat of blubber.

Bears don't fly, but they surely know how to walk, and run, and swim very well. I was brought up to believe that the Jungle Book song couldn't be true, but bears can dance too ! And get themselves some bare necessities while they're at it: a sort of fish slapping dance.

If all this makes you feel bad for the poor salmon though, you might just be looking out for family -- so cheer up and have a whale of a week.