|
Predators eat rotten meat, lightning strikes fish, Everest scrapes the stratosphere
Q: Why are predators and, of course, scavengers unaffected
by rotted meat? Scott, Tucson, Arizona
A: Predators and scavengers can eat rotted meat thanks to a
germ-hostile digestive system. All vertebrate predators have remarkably similar
systems: a short pipe — six times the body length
— with a bulge (the stomach)
in the middle.
Wolf and scavenging ravens feeding on elk that the wolf
killed. [Douglas Smith, National Park Service]
Because it’s short, food doesn’t stay long in the gut.
Bacteria have little time to multiply and cause problems. The stomach, moreover,
brews a vicious batch of hydrochloric acid that not only dissolves gobbled meat
and fat but also kills most bacteria and other microorganisms.
"Practically the whole gastrointestinal tract of a carnivore
is sterile," says Barry Groves, British nutritional scientist.
Rotting meat is rich in protein, amino acids, fat, lipid
components, and minerals. Scavengers usually find dead meat soon after a kill so
it loses little nutritional value. Eating rotted meat helps the species to
survive.
"Hunger will drive most animals to feed on what’s available,"
says Dan Stahler, project biologist with the Yellowstone Gray Wolf Restoration
Program, National Park Service. "These meat eaters can handle a high bacterial
load due to their short digestive system and appropriate digestive enzymes and
acids."
So can we. In Europe, people "regularly hang beef three weeks
in a fridge before eating it," says Groves. Inuits leave fish to rot for months.
By then, according to the anthropologist and Arctic explorer, Vilhjalmur
Stefansson, it has the consistency of ice cream. "At first repelled, he grew to
like it," says Groves.
Further Surfing:
Second
opinions: The design of our digestive organs and digestive enzymes today by
Barry Groves
University of California, Berkeley: Scavengers benefit by dining with wolves by
Dan Stahler
Lightning strikes fish
Q:
If lightning strikes the ocean, do the marine animals get hurt or killed?
Vicki, Sault Ste. Marie, Minnesota
A: A single lightning stroke can deliver a billion electron
volts and 100,000 amps. Air within a lightning stroke can be hotter than the
Sun’s surface.
Lightning hitting the open ocean [Moonraker
Australia Communication Systems]
So, yes, if such a lightning bolt directly hits a marine
animal swimming on the surface, it will undoubtedly hurt or kill her.
But, that’s not quite your question. What if the bolt strikes
the water nearby the animal? Lightning comes in all shapes and sizes. What if
it’s a lesser discharge? Ah, this gets tricky but it would probably harm her, at
least. If she’s down deep, though, she’s safe.
When lightning strikes the ocean or other large water bodies,
it spreads out over the conducting surface. It also penetrates down and can kill
fish in the nearby region, says Don MacGorman, physicist at the National Severe
Storms Laboratory (NSSL).
"Lightning strikes have killed or injured people on the
surface more than 30 yards away," says David Schultz of the NSSL.
In fact, the 45th Weather Squadron lists water as
the second most dangerous place to be during a thunderstorm. (The first is an
open field.)
Lightning, however, rarely strikes most of the open ocean
although some sea regions are lightning "hot spots". The Gulf Stream, for
example, where fish abound, has as many lightning strikes as the southern plains
of the USA.
Lightning-producing storms arrive on the west coast of the
U.S. frequently during the winter, says Schultz. "Winter storms passing off the
east coast often erupt with electrical activity when they cross the warm waters
of the Gulf Stream."
But, as Schultz says: "We really have no idea about the
mortality rate of marine animals due to thunderstorms." Fortunately, only 10 to
20 percent of humans hit by lightning die and probably the same holds true for
the animals.
Further Surfing:
NOAA/National Severe Storms Laboratory: Lightning impacts, avoidance, and
weather-related research
NASA: Where
lightning strikes
Moonraker
Antenna Systems: Lightning at sea
West Virginia
Lightning: Lightning formation illustrated with animated displays
Museum of
Science, Boston: How lightning happens
USA
Today: Lightning science by Jack Williams
Everest scrapes the
stratosphere
Q:
Mount Everest is so tall it actually touches what? Melissa, Kashmir, India
A: The stratosphere. Mount Everest pokes two-thirds of the way
through the air of the Earth’s atmosphere to the ozone-producing stratosphere —
5.5 miles (8.7 km) up. Stratosphere air contains little water vapor or dust;
only wispy cirrostratus clouds streak the distant sky. Storm clouds, however,
can and certainly do form around the landmass of Everest.
The Himalaya Mountain maze from space, yellow arrow points
to Mount Everest. Astronauts, orbiting at 5 mi/sec (8 km/sec), have seconds to
find it. [NASA]
The mountain peak (29,035 feet) scrapes the jet stream. In the
winter, the high-flying jet stream hurtles in from the north and batters Mount
Everest with hurricane-force winds exceeding 177 mph (285 km/h).
Few Earthlings venture this high. Men struggled from 1921 on
to scale the peak.
On the first expedition, A.F.R. Wollaston, the medical
officer, saw a bearded vulture soaring over North Peak at about 25,000 feet. At
22,000 feet, a naturalist on the next expedition discovered Earth’s highest
permanent residents. Some minute black spiders (Attid spiders) lurk in crevices
among rocky debris. What they eat is a mystery. No plants or any visible sign of
organic life lives this high.
Finally, in 1953, Edmund Hillary and Tenzing Norgay succeeded
in climbing Earth’s highest mountain.
Further Surfing:
Panoramas: Turn slowly around and see the 360-degree top-of-the-world view from
Mount Everest’s summit. Photos by Roderick Mackenzie
NASA: Find
Mt. Everest in the maze of mountains
Expeditions: Fauna and flora on the mountain
Peakware World
Mountain Encyclopedia: Mount Everest
(Answered Mar. 5, 2004)
|