Q) How far out to sea do I need to get to be safe from mosquitoes?
Bernadette Pampuch Rivero, Ragged River, Bahamas
A) BE PREPARED to row your boat a long way if you want to escape the blood-sucking proboscis of the skeeter. Jack Petersen, an entomologist at Florida A&M University who researches mosquito control, says the black salt-marsh mosquitoa critter he calls "Florida's public enemy number one"is often found 20 miles offshore. Of course, none of the world's 3,000 species can actually smell you from that far away. The maximum distance from which a downwind mosquito can sniff blood, so to speakby detecting the CO2 and lactic acid that humans give offis about 60 yards. Long-distance mosquito travel is more a function of riding wind currents than flying with intent. Ultimately, the question to ask is not where but when: If you go out on the water at midday, when heavier breezes blow toward shore and send the bugs back to their nests, you might need more sunscreen, but you'll greatly reduce the need for deet.
Q) Is there really such a thing as a runner's high? I've been a long-distance runner for years, and I've never experienced it.
Eric Keszler, Cordova, Tennessee
A) THE TERM "runner's high" has been around since the jogging craze took off in the mid-1970s and is used to describe anything from a mildly elevated mood to a narcotic-like euphoria that might come over you during or after any hard workout. While the sheer number of people who claim to have experienced this buzz points to something more than a placebo effect, science has yet to verify or explain it. Conventional wisdom attributes the high to the brain's release of morphine-like chemicals called endorphins. But Virginia Grant, a psychology professor at Memorial University of Newfoundland, thinks a more complex cocktail of brain chemicals is at work. Her studies found that rats seem to experience pleasure when running on a wheelwhich indicates a probable endorphin rushand she points to earlier tests showing that, if given the chance, a rat will run itself to death, as if literally addicted. This suggests to Grant that dopamine, a major chemical behind addictive behavior, may be present as well. If this is true for humans, then it may be that those folks with more addictive personalities are likely to experience a runner's high, while others might only feel somewhat better. Check back in a few years.
Q) Is it true that raptors can't release their prey in flight? I've heard stories of ospreys drowning and eagles crashing because they latched on to something too big.
Hannah Shepard, Bralorne, British Columbia
A) SOMETIMES A RAPTOR whose eyes are bigger than its wings will attach itself to prey that's so weighty it's unable to get off the ground. Pat Redig, director of the University of Minnesota's Raptor Center, says this is because the birds have special ratcheting tendons that allow them to grip tightly even when their muscles aren't flexed. The tendons consist of two notched tubes, one inside the other; when the raptor makes a grab, the notches catchthe same action that allows perching birds to hold on to a branch while asleep. Unhitching the tendons requires a quick flex of the musclesbut quick is a relative term when you're an osprey frantically trying to detach from a deceptively big carp. If the raptor can't let go in time to pick up wing speed, a heavy fish or animal can drag it down. Still, when a bird does crash, it's usually not a result of mechanics so much as stubbornness. Once, Redig took his pet red-tailed hawk out to hunt, and the hawk "captured" a very large rabbit and was clearly determined not to let go. "The rabbit," he recalls, "scurried down a hole, leaving the hawk desperately trying to keep its head above ground." Call it the earth inheriting the not so meek.