From Penguin Life and Being In Sync
Everybody, it seems, has a question about something, no matter how offbeat or trivial it may be. Here are a few of the more entertaining ones posed to New Scientist recently, along with the just-as-entertaining answers.Cold Feat
Q: Why don’t Antarctic penguins’ feet freeze in the winter?
To avoid losing too much heat, penguins have adapted to their environment, preserving a central body temperature of 104 degrees Fahrenheit. Their feet present particular problems, since they have a big surface area (as much as one-third of the animal’s total body length) and can’t be insulated by feathers or blubber.
Two mechanisms help address the problems. First, the penguin’s body can actually control the rate of blood flow to the feet by varying the diameter of vessels supplying the blood. In cold conditions, that flow is reduced; when it’s warm, the flow increases. Humans do this too: Our hands and feet become white when we’re cold, pink when we’re warm.
Second, penguins have “countercurrent heat exchangers” at the top of their legs. Arteries supplying warm blood to the feet break up into many small vessels, as do the veins, bringing cold blood back from the feet. Because these capillary beds are so close to each other, they modulate the temperature of the blood in both directions.
In winter, penguins’ feet are held a degree or two above freezing—to minimize the heat loss while avoiding frostbite.
Going My Way?
Q: When two people walk together, why do they walk in sync much of the time?
It’s an unconscious tendency to show that they agree with, and fit in with, each other, according to Desmond Morris, a zoologist and specialist in human behavior. It’s also a signal to others that “we’re together, we’re synchronized.” Some studies suggest that we adopt the mannerisms of our companions, especially our superiors, like when we cross our legs in the same direction as the boss does or scratch our noses simultaneously.
Next time you walk alongside somebody, walk out of step. Then try to follow the conversation you’re having. You’ll soon fall back into step; it’s more natural to watch where you’re walking and then turn to look at the other person. Communication is easier when you’re in close proximity and your faces are relatively stable. Also, walkers have a slight side-to-side sway. Two people out of step would simply bump shoulders every second.
Leaping Fish and Nerves On End
Tank HeavenQ: Following a recent bereavement, we’d like to know why our fish keep jumping out of their small aquariums.
Fish jumping out of small tanks is a common problem for enthusiasts, and it’s why some people put a glass cover on their aquariums. There are a few theories. In the wild, the fish may jump to rid themselves of ectoparasites. They may also be trying to avoid predators or unpleasant interactions with other creatures, or even to show off to other fish in some previously unknown courtship or territorial ritual.
To captive fish, the air on the other side of the aquarium glass looks like water. In fish lore, the water is always cleaner on the other side. In the meantime, our sincere condolences for your loss.
Nerve Endings
Q: What bodily changes cause us to have a dry throat when we’re nervous?
When you’re nerve-ridden during public speaking, the body is set into the fight-or-flight state. This is caused by an activation of the autonomic nervous system. It’s seen throughout the animal kingdom and has evolved to help animals deal with danger—when escaping from predators, for example.
The nerves are selectively activated, depending on how important they are for response. Because eating is not considered to be vital at this time—you want to just get the heck out of there—the nerves that control the salivary glands are suppressed, so your mouth dries up. Your pupils dilate, and the blood vessels to your muscles and heart widen to get blood to the most important organs for whatever action is necessary.
In a tense or dangerous situation, your body shuts down all unnecessary functions, including the digestive system. Your salivary glands are part of it. You don’t need to digest your last meal if a lion is trying to make you his next. This is also where butterflies in the stomach come from.
The Truth About Dogs and Cheese
Common ScentsQ: Why are dogs’ noses black?
While most dogs have black noses, not all do. The noses of vizslas and Weimaraners, for example, are closer to their coat colors—golden rust and gray, respectively. And it’s not unusual for puppies of any breed to start out with pink noses that darken as the animal matures. A Shetland sheepdog we know retained pink on the insides of her nostrils for her entire life.
Dogs have most likely developed black noses as a protection against sunburn. While the rest of the animal’s body is protected by fur, light-colored noses are exposed to the full force of the sun’s rays. Pink-nosed dogs and breeds that are hairless or have very thin hair on their ears need to be protected with sunscreen when they go outdoors, or they risk the same sort of cancers and burns that humans do.
In addition, dog breeders have long singled out a black nose as the only acceptable color for many breeds. Though this is based on human preference, it still serves as a selective influence for people breeding pedigreed dogs. This adds a bit of human-directed evolution to what was already a natural tendency toward black noses.
Stringing Us Along
Q: Why does grilled cheese become stringy?
The uncooked cheese contains large protein molecules more or less curled up in a fatty, watery mess. When you heat cheese, the fats and proteins melt, and if you fiddle with the fluid, the molecules can get dragged into strings. Grab a bit of the molten cheese and pull. You’ll get a filament, in the same way that you can draw and twist cotton batting into yarn.
Ace in the Hole
Q: I recently did a parachute jump for charity. The one disconcerting thing about the jump (apart from my fear of heights) was the large hole at the top of the parachute. Why is it there?
In the days before the apex vent (that disconcerting hole at the top of the parachute canopy), the only way that air under the parachute could escape was to spill out from one edge of the canopy, tilting it and throwing the helpless parachutist to one side. As the canopy swung back, more air would spill out from the opposite side, setting up a regular, pendulum-like oscillation.
As you can imagine, hitting the ground during a downswing was hazardous, especially if it was also a windy day. The apex vent, by allowing the air to leak out slowly, prevents this wild oscillation and makes for much safer landings. Another benefit of the apex vent is that it slows down the opening of the parachute. Without the vent, air would inflate the canopy much more abruptly. That could damage the parachute or bring tears to the eyes of (particularly male) jumpers.