Know your roe: Why flying fish really don't


Q. From a Michigan reader: "I wonder if you might take up the argument about whether "flying fish" can really fly. I personally think they can. I have seen them airborne the full length of a cruise ship, about 900 feet (270 meters). That's a long way to glide!"– T. Anastasio

A. A clue: If the name says it flies, it probably doesn't– cf. the flying lizard (on winglike membranes at its sides, it too glides through the air), flying lemur (fur-covered membranes permit gliding leaps), flying frog (web-connected toes do the same), and flying squirrel (tree to tree on winglike membranes).

Or if it does fly, other trickery awaits: The flying fox is not a fox but does have a foxlike muzzle and small pointy ears, and can fly with the best of them (it's a bat).

So now to flying fish: They're marine species of the family Exocoetidae, not with wings to beat for "powered flight" but capable of high speeds in the water, then going airborne for a glide on their long, wide, stationary pectoral fins, says University of Idaho zoologist James Nagler. One species, the characin, notes Columbia Encyclopedia, does actually "fly" short distances by buzzing its fins. In any event, says, favorable winds could carry some flying fish as much as 600 feet (180 meters) in a single glide, farther for multiple or skim glides.

This behavior is usually a means of escaping predators and/or entertaining cruise ship passengers!

Q. This famous map puzzle has kicked around since the mid-1800s: What is the least possible number of colors needed to fill in any map so that adjacent countries or provinces are always colored differently? –G. Mercator

A. Four colors suffice, says American Scientist magazine (reviewing Robin Wilson's book of that title), which has been known– or suspected– for a long time. But how to prove this? Many have tried, many have failed. Then in 1976, Kenneth Appel and Wolfgang Haken seemed to crack the four-color map puzzle, by reducing it to 1,936 special cases, a feat requiring some 1,200 hours of computer time. "The proof depended on electricity and experimentation," Wilson writes.

The new type of cyber-proof raised eyebrows and skepticism. A proof should come from understanding, not a mechanized bludgeon, objected many in the math community.

The debate continues today. "It doesn't seem likely, but the hope is that a new, more satisfying reformulation of the problem is possible." Any bright ideas out there?

Q. Here's one for the books: How was it determined that the normal body temperature is 98.6 degrees Fahrenheit? –Keith

A. Erroneously! Though this precise-sounding number has been known to generations of parents and doctors, it's wrong, says Temple University's John Allen Paulos in A Mathematician Reads the Newspapers. Recent tests involving millions of measurements found a figure of 98.2 F.

But don't blame German physician Dr. Carl Wunderlich (1815-1877), who did the original statistical study of normal body temperature of thousands of people in Europe. The Dr. actually found a range of temperatures, says Paulos, then averaged them and sensibly rounded to the nearest degree: 37 Celsius! When this was converted to Fahrenheit, however, the rounding of the two-digit figure was forgotten, and 98.6 was taken to be accurate to the nearest tenth of a degree.

"Had the original interval from 36.5-37.5 Celsius been translated, the equivalent Fahrenheit temperatures would have ranged from 97.7 to 99.5."

As one "Fever Phobia" website puts it, "A curse on the person who invented the arrow pointing to 98.6 on many old thermometers!" In truth, temps can vary from morning to evening, person to person, kids to adults, how the temp is taken (oral vs. rectal) or phase of the menstrual cycle.

Send Strange questions to brothers Bill and Rich at