Salt Flats

Maybe you've heard of Death Valley in Nevada or the Bonneville Salt Flats in Utah. These are two examples of what are called "salt flats", if the Salt Flats in Bonneville Salt Flats didn't give it away already. Various types of flats are the remnants of short-lived lakes or endorheic basins, basins that collect rainwater and runoff, but don't let anything escape. Usually these flats are partially filled with water during the rainy season, but then dry up in the dry season. As the water evaporates, winds shape the land to nearly perfectly smooth.

Salar de Uyuni, Bolivia becomes a mirror when covered in shallow water

Salt flats are, as their name would suggest, very salty. Minerals run into salt flat basins from the nearby surroundings when it rains, leaving only the hardened minerals behind when the water has evaporated. The result of this is that the top layer of salt flats are entirely composed of hardened salt, primarily common table salt. Because of this, some salt flats are harvested for resources.

Salt crystals form on the surface of salt flats

Salt can be harvested from Salar de Uyuni

Salt flats are almost entirely devoid of plant and animal life. With such high concentrations of salt, plants are entirely incapable of living, let alone the extreme dryness of the dry seasons. With no plant life or water, there's no incentive for animals to live out in the flats, and so they don't. However, salt resistant plants can sometimes live on the near outside of a salt flat.

Humans have found a use for salt flats relatively recently, other than for resources. Because they are so extremely flat and expansive, they turn out to be ideal places to race. Whenever a land speed record is broken, it is broken on a salt flat. Extremely fast cars must be very low to the ground, so flats allow for these vehicles to drive without the interference that they would get elsewhere. And because nothing lives in these salt flats, a racer can have no worry of harming the environment (apart from chemical emissions). The Bonneville flats that I mentioned earlier are used extensively for racing and speed testing.

The fastest cars are the lowest to the ground.

Salt flats can be fragile, however. The crystals that form on the surface are delicate, so people and vehicles can make a huge impression. For this reason, some flats are protected by the U.S. government. Death Valley is one of those places, people are only allowed to walk or drive along specified paths.

The House Centipede

The common house centipede

Most people have seen one of these freaky creatures, and probably has them running around inside their homes. In fact, these bugs are so common that nearly every one is probably living with them, whether they know it or not. Despite their creepy appearance, these centipedes really aren't all that bad.

One of the major fears with any small critter is it's ability to bite or sting. The long legs of the house centipede, or Scutigera Coleoptrata, are eerily reminiscent of the legs of a spider, which leads many to believe that it is capable of biting and inflicting pain like many spiders. This, however, isn't necessarily true. House centipedes use modified legs to inject poison into their prey, but this sting is very weak. Even if a centipede did decide to bite you, it'd be unlikely that the creature could actually puncture your skin. On top of their weak stings, they are very nervous creatures. They are likely to scurry away at the first sign of light or movement, so you usually have nothing to worry about. Even if one did, somehow, manage to bite you, you'd only experience a little pain and some swelling, nothing serious.

Close up of a centipede with it's modified legs shown.

These centipedes are insectivores, meaning that they live off of insects and arachnids. They are good creatures to have in ones home because they will help to keep the population of other insects down, and it's nearly impossible to get rid of them anyway. Usually coming out during the night, these centipedes will take on anything from pesky spiders to dangerous wasps. Centipedes are intelligent creatures, at least when it comes to their hunting strategies. If a centipede were trying to eat something small, say a bedbug or spider, it might try to wrestle it and sting it to death. However, if a centipede wants to take on something more dangerous, say a wasp, it will bite it's foe and then back off, letting the poison kill it's opponent. House centipedes, unlike most other types of centipedes, have very well developed faceted eyes, which provides them a uniquely clear visual perception of their surroundings. But even with these complex eyes, house centipedes still rely mostly on their antennae when hunting.

Centipede killing and eating its prey

This type of centipede is usually between 25 and 50 millimeters long with 15 pairs of long legs. They have three dark dorsal stripes running their length. Centipedes usually give birth during the spring, and their larvae look like miniature versions of themselves, with only 4 sets of legs. Centipedes molt several times throughout their lives, and it is during these molts that a young centipede begins to gain more legs.  Because of the set up of their legs, house centipedes can run extremely fast for their size. You've all seen them scurrying into their holes whenever the light turns on. They can reach speeds of more than 0.4 meters per second (or 1.3 ft/sec). Another interesting feature of the house centipede is that it can detach any of it's legs if it's threatened. This skill comes in very handy if it's being pinned. And to top it all off, they can live for up to 7 years.

All in all, house centipedes are pretty amazing. They may look scary, but they hardly ever hurt humans. They aid in the never ending battle against insect home invasion and usually stay out of the way. Next time you see one of these critters scurrying across your basement floor, try to resist the urge to step on it.