Question: With each new generation seemingly taller than the one before, where might we humans be in 100 years, or 1000? Will we need bigger clothes, bigger beds, bigger cars? Or are there limits to this?
Answer: Limits, you bet, says University of Chicago organismal biologist and anatomist Michael LaBarbera. While it's true average heights have gone up in the last 150 years, probably due to better nutrition (in terms of balanced diets, not caloric intake), folks in North America and Europe at least have probably just about peaked out.
In fact, Nature imposes a fundamental stature-cap: Mammals in general load their bones to about a quarter of their breaking strength during routine activities. If you doubled height, bone cross-sectional area would increase fourfold (radius squared), while weight (volume) increases eightfold (2 x 2 x 2)! Our bones would be overloaded, and breaks would be commonplace.
Bad as this sounds, things would actually be even worse, says LaBarbera: 12-foot-tall humans would be prone to collapsed arches, bad knees and excruciating back problems; 18-foot tall humans would be immobilized.
So, height limits, absolutely. But fat chance we've already peaked in body girth.
Question: How do dollar bill changers know when someone has slipped in a bogus buck?
Answer: One method uses magnetic heads like in a cassette tape recorder to read the magnetic ink signals coming off the bills, says HowStuffWorks.Com. Electrical conductivity is also telltale, as are the fluorescent properties of the ink and paper, or optical properties read by a photocell or camera. A good bill changer will use several of these.
Machine con-artists counter with the half-bill ruse, or the attached-string larceny, or even unplugging the machine in midstream to confuse its read.
A faster con job nowadays is to use color copiers and printers to run off facsimiles passable to a harried checkout cashier, ignoring micro-writing, watermarks, embedded security strips, color-change ink, very closely spaced lines. In defense, a clerk may employ a "counterfeit detector pen" to smear on an iodine solution that turns black against cheap wood-based papers but not against the fine-based papers of "legal tender."
Question: How does a python, half the size of a gazelle, manage to swallow it whole? How long will the meal last? Warning: gross snake gastronomy ahead.
Answer: Needle-like teeth fix the prey in place, helping saliva-prime it for the big swallow, mouth swung open wide by flexible ligaments, elastic muscles and wide-hingeing jaws, says Curator of Herpetology F. Wayne King of the Florida Museum of Natural History.
A python swallowing a gazelle starts at its nose, and as the gazelle is engulfed, its legs fold naturally and lay along its sides, a "bolus bullet." It may take several minutes for the food to pass from mouth to throat to gut, which expands as needed because while there are ribs, there is no rib cage. A special trachea hookup allows the snake to pause, take a breath or two, and return to swallowing without choking.
A meal the size of a gazelle might take a week or more to digest, then the snake sinks into a low-metabolic torpor and doesn't need to eat again for a few months, says King.
But the python's no glutton. "By the time it eats again," says James Kalat in "Biological Psychology," "your own total food intake will be larger than the snake's."
Send STRANGE questions to brothers Bill and Rich at strangetrue@compuserve.com