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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.
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