Here, kitty!

Q: Do big cats such as lions, tigers, and leopards purr

like housecats? ­G. G. Williams

A: There's no doubt that big cats can purr... just ask anyone who's ever worked with them in a zoo or circus, says Mark A. Pokras, director of the wildlife clinic at the Tufts University School of Veterinary Medicine. "Of course, they purr much louder than your typical household cat– tends to vibrate your whole body if you are close by."

Tiger trainer Sara Houcke, of Ringling Brothers Circus, told the New York Times that her tigers purr to her and she purrs back. That way, when the tigers aren't purring, she "knows they are in a bad mood" and stays away from them.

But being there within earshot when a big cat's in the mood is rare enough that University of Minnesota biologist Craig Packer says he's never heard a purr in 25 years of studying lions in the wild. When lions do purr, it's brief, probably issued only on the exhalation phase. So the lion-sound probably has little social significance.

The same hyoid bone structure that lets a housecat purr in and out hooks up in bigger cats with fibroelastic tissue at the vocal cords, limiting purring but acting like a slide trombone to unloose those mighty roars, says

Q: Right at this moment, who are the happiest people on Earth? Where do they live? Are they rich? Working? Married? With kids? In love? Just won the lottery? ­P. Newman

 A: Many factors we might expect to be associated with

Happiness– age, gender, ethnicity, physical disability, intelligence, urban vs. rural residence, parenthood– in fact are not, says Georgia Southern University psychologist Michael Nielsen. What's more, assuming basic needs are met, more money won't bring happiness (see Adjustment and Human Relations, by Tricia Alexander).

Still, differences exist, and Danes and Swedes rate themselves as happier than other nationalities. Working people aren't necessarily happier, but dissatisfied workers are unhappier. The same for marrieds. People with kids aren't happier, except for a blip upward when kids leave.

Being in love will bring the glad bluebird, as will winning the lottery, though neither is longlasting.

"So, I guess you could say the world's happiest people are those living in Denmark or Sweden, who moments ago won a lottery, who enjoy their work and marriage, whose kids recently left the nest, who get regular exercise, who are extroverted, have high self-esteem and a feeling of control over the environment, and are optimistic and religious. I think this means there are two of them!"


Q: Neither heat nor cold can mar it, acid won't attack it, slipperiness is its hallmark, the Manhattan Project (atom bomb) put its uranium-corrosion-resistant powers to use, much later Du Pont spread it on kitchen pans. You'll find it today also stretched into Gore-Tex water-repellent breathable clothing, as well as in dictionaries as "polytetrafluoroethylene." Identify this polymer superstar. ­E. Teller

 A: Teflon, as detailed by Newsweek magazine. As to how something that prevents food sticking during cooking will itself stick to a pan, acid is used to etch tiny pits and grooves in the aluminum, then a Teflon emulsion is poured into the irregularities and baked on, says University of Central Arkansas chemist Conrad Stanitski. The heat locks the Teflon in place, thus providing the slick no-stick surface cooks the world over have gotten stuck on using.

(Send STRANGE questions to brothers Bill and Rich at