The Wild File
Q:Does an animal feel more pain if it has a large brain?
Joe Farago, Denver, Colorado
A: In other words, can you crush bugs without a guilt trip? Maybe. In order to feel the fatal thwap of a flyswatter, a critter needs special equipment like pain receptors, sensitive nerve fibers that send nerve impulses to the spinal cord and brain. While all fish, reptiles, amphibians, and mammals have pain receptors near their skin, some have more than others: Anglers can sleep a little easier knowing that a rainbow trout's mouth has fewer pain receptors than a dog's. But scientists are pretty clueless as to whether crustaceans, mollusks, and insects with their small brains and unsophisticated nervous systems feel true hurt. Take the common American lobster. Like all hard-shell invertebrates, it has no spinal cord, no pain receptors near the outside of its body, and no cerebral cortex (the area of the brain that translates pain impulses into the sensation of pain). Yet watch a lobster try to claw its way out of a pot of boiling water, and it's pretty obvious that the little guy is experiencing something. Exactly what, though, is hard to say. "We don't know if lobsters feel pain," says Edward Kravitz, a professor of neurobiology at Harvard Medical School, adding yet another disclaimer. "Since pain is a perception, we often don't know whether people feel it either."
Q:Could you please explain to me how a propane lantern makes light. I studied those mantles in many an ice hut for years. How's it done?
Matt Peterson, Washington, D.C.
A: First, a little Thermodynamics 101. Back in 1901, an aging German physicist named Max Planck made a brilliant discovery. He found that any atom, when sufficiently heated, ejects electrons and to remain balanced subsequently releases photons, which are energy in the form of heat and light. Planck recognized that different elements give off light at different temperatures and that certain substances give off more light than others which is where the lantern comes in. The lantern's mantle, a small woven bag that acts as a wick, is a blend of magnesium, cerium, and the rare-earth metal yttrium. Pump propane vapor into the chamber surrounding the mantle, put a match to the mantle, and the magnesium and cerium ignite like kindling. But to get that familiar yellow light, you've got to increase the flow of gas and oxygen so the propane and mantle burn hotter. At temperatures between 1,000 and 2,000 degrees Fahrenheit, yttrium burns brighter than any other metal, shedding photons like a dog shaking off water and burning only minimal gas. It's an elegantly simple design often taken for granted, it seems, unless you're a man sitting in an ice hut for a really long time.
Q:Why do small birds sometimes relentlessly attack larger birds?
D. Murray, Morris, Manitoba
A: Because birds, like all creatures, instinctively realize the power of "mobbing," as it's officially called. "Mobbing looks and sounds aggressive," says Sally Conyne, a research director with the National Audubon Society, "but it rarely leads to injury or death on either side of the brawl. Its main purpose, beyond saving the babies, is to teach the young to recognize the enemy for when they're grown-up birds entrusted with protecting the nest." Say a hungry crow casts an evil eye toward some grackle fledglings. It won't be long before the adult grackles shake their branches, calling attention to the interloper, and gather a posse to run it out of their territory. As soon as they flush the crow from the tree, the grackles launch a valiant aerial dogfight, swooping at it from behind and sometimes diving at its tail feathers and feet until it flees. The crow gets sweet revenge, in a way, should a hawk, eagle, owl, or, yes, human, trespass on its territory: As many as 50 of its crow brethren will dive-bomb the invader until it leaves. Don't think that you're safe from harassment just because you've got a big brain and opposable thumbs, Conyne warns. Hitchcock's The Birds got it right.
Q:Taking into consideration the movement of the heavens and earth, how fast am I going if I'm standing still on the equator?
Mark Benallack, Muskegon, Michigan
A: It's a matter of perspective. To someone standing next to you at zero degrees latitude, you'd appear stationary. To a martian hovering over the earth, you'd appear to be spinning at 1,041 miles per hour. Icarus, looking back at you from the sun, would see that in addition to riding the terrestrial Tilt-A-Whirl, you are orbiting the home star at approximately 60,641 mph. From an outpost on the edge of Andromeda Galaxy, the earth would be seen spinning, orbiting, and finally spiraling through the Milky Way, at an average speed of 584,601 mph. Add this all up and you are travelling at a top speed of 646,283 miles per hour. But not so fast the universe itself is expanding, at an immeasurable rate, so it is ultimately impossible to quantify how fast we're really going. "You'd need a reference point outside the universe," notes Mike Kobrick, a researcher at NASA's Jet Propulsion Laboratory in Pasadena, California. "I'm talking about higher dimensional space. I know I don't have that kind of perspective." Think you do? Please don't write us.