February 27, 2009
This may look like a flying saucer of movie fame, but it’s really an atmospheric phenomenon called a “sprite.” Sprites appear 35 to 80 miles above the earth’s surface; they can be set off when the lightning from a thunderstorm (only 7 to 10 miles high) excites the electric field farther up in the atmosphere. Though they appear above most thunderstorms, they appear so briefly—less then a second—and so high up that it’s not so shocking that they weren’t discovered until 1989. Like other similar phenomena called “elves,” “trolls” and “goblins,” sprites dance in the sky and are thought to be the source of some UFO sightings.
February 26, 2009
Six-o-clock in the morning is when the action begins at the National Zoo. Think you’re grumpy without breakfast? Just imagine how Mei Xiang and Tian Tian, two of the Zoo’s giant pandas, would feel without their bamboo.
Yesterday morning, I joined a zoo employee in a truck marked, “The Bamboo Never Stops,” as he delivered approximately 250 stalks of the treasured plant to the pandas, apes, elephants and several other species that enjoy the low protein, high fiber content of the leaves and stalks.
When we returned, it was off to the kitchen. With the radio softly playing in the background, we watched as nutritionists mixed bananas, lettuce, apples, carrots and corn with dozens of animal-specific biscuits. They weren’t the warm and toasty buttermilk biscuits you may enjoy for breakfast, but chicken-nugget sized combinations of oats and grains lightly flavored with citrus.
Every animal has a personalized diet, designed by a team of zoo nutritionists. The diets account for personal tastes, whether the animal runs around a lot or remains stationary, as well as age and health. For example, one gorilla received a biscuit and greens along with a beet, onion, cucumber, melon and banana.
If you ever host a dinner party for the following zoo animals, here’s what you need to know:
For penguins: These flightless birds have a taste for seafood. They’d be happy with a variety of fish, krill or squid. And no need for silverware! It’s recommended that penguins be hand-fed.
For fruit bats: Don’t let their name deceive you. These guys are picky eaters. Depending on the crowd, you may be forced to serve fruit, nectar, pollen, insects, blood, small mammals, birds, lizards, frogs or fish. It’s best to make this one a pot luck.
For Asian small-clawed otters: You may be better off going to a steak house if you have these furry guys over. Minced beef, fish, hard-boiled eggs, and locally available shellfish and crabs should be provided. Though they may not mind a bit of dog or cat food.
Wondering what your local lion or zebra is eating? You can find more nutrition advice at the American Zoo Association Web site.
– Joseph Caputo
February 25, 2009
What’s your take on this? Dorky? Effective?
(Hat tip to the Knight Science Journalism Tracker)
February 24, 2009
Science can turn you into a full-time skeptic (as my friends discover at some of the oddest times), but that’s not a bad thing. I’m sure that Smithsonian’s favorite skeptic, James Randi, has had plenty of cocktail conversations in which people try to convince him that they found the magic cure to all his ills, or some other form of woo. But then, he solicits this sort of thing—the James Randi Educational Foundation offers $1 million “to anyone who can show, under proper observing conditions, evidence of any paranormal, supernatural, or occult power or event.”
As the foundation notes: “To date, no one has passed the preliminary tests.”
In this video from the Amazing Randi, we can get a hint of the kind of person who applies for the $1-million-prize. This time it’s a dowser. Watch the video to learn how dowsing really “works.”
Maybe the guy should have watched the next video before submitting his claim. In it, a group of dowsers in the United Kingdom are subjected to a double-blind test of their dowsing ability. Will anyone pass the test?
(Hat tip to Bad Astronomy)
February 23, 2009
Those adorable little meerkats aren’t just good TV fodder—they’re great research fodder as well.
A couple of University of Zurich scientists, publishing in the March issue of the American Naturalist, studied alarm calls produced by meerkats and Cape ground squirrels that lived sympatrically on the Kalahari Desert.
Alarm calls produced by animals come in two flavors: One type denotes only a level of urgency, while the other includes information about predator type and how individuals should respond (“functionally referential” signals). Theories of how these alarm calls evolve have suggested that the type of alarm call used by a species is influenced most by how it responds to threats. Species that use different strategies for escaping different predators, logically enough, would be best served by functionally referential signals. But creatures that use a single strategy would need only the urgency level in their alarms.
The meerkats and Cape ground squirrels, though, respond in a similar fashion to threats—they run for cover, escaping down bolt holes into burrows that the two species often share. The Cape ground squirrels use the urgency-dependent alarm calls, as would be expected by the theory, but the meerkats use functionally referential signals. Why the difference?
The Cape ground squirrels eat vegetable matter that they can find close to home, while the meerkats have to venture farther for their meals of insects and other small animals. The Cape ground squirrels don’t lose much by retreating to their burrows, because they aren’t that far away. The meerkats, though, can’t run home every time they’re threatened, because the cost would be too high (lost yummies). They respond differently to different threats (such as by moving away from an ambush predator like a jackal instead of returning all the way to the burrow and trying to wait the jackal out). In addition, the meerkats have to be able to respond in the same way to a threat, because if one runs in the opposite direction of the group, he could be toast (single meerkats and small groups have a higher likelihood of being eaten by a predator).
This video (meerkats responding to the “threat” of an ultralight plane flying above) comes from YouTube user nyatnagarl who has made many videos of the meerkats at the Hanover Zoo in Germany and has noticed:
The meerkat group react[s] quite differently to the aerial encounters made in this location:
* Passenger jet planes high in the sky – usually ignored, but at sunset, when they are caught and illuminated in the sky by the last rays of the sun, they are watched closely, but an alarm is never raised.
* Small propeller planes (Cessna, etc.), low flying – sometimes completely ignored (i.e., not even the head is raised), sometimes watched. Since there is a small airport nearby, they know these planes very well, and understand they pose no danger. In general the sound of the classic piston engine aircraft is associated with “not dangerous”, you can often hear an engine drone in parts of the videos I have posted.
* Anything that has a triangular shape like hang gliders, ultralights – will usually cause an intense warning. It is worse when the flying object is silent (like hang gliders) – this will usually cause an at least partial retreat of the family into the burrow. A silent slowly moving object with swept wings probably reminds them most of a predatory bird.
* Hot air balloons – they do not like these at all. Although they are usually distant, the silent, looming presence on the horizon seems to disturb the meerkats deeply. They will usually watch these intently and most activity will cease until they disappear.
* Zeppelins – we don’t get these very frequently but when the “Zeppelin NT” flew over the enclosure at low altitude one afternoon it was considered the ultimate enemy. The meerkats raised alarm, disappeared into the burrow and did not reappear for the rest of the day!