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Come on… you have to admit you’ve wondered this, right? First, let’s figure out how venomous snakes can even live at all, considering a deadly venom is inside their body. It’s important to understand the difference between venom and poison. Generally, poison is something that has ill effects when you ingest it, or when it gets on your skin. For example, some toads are poisonous because they secrete a substance that is harmful if swallowed. Venom, on the other hand, is harmful when it gets injected into your bloodstream. Snake venom is only toxic when it gets into your blood. You can think of a rattlesnake’s fangs as syringes for injecting their venom. Well, snakes store their venom inside special glands, which keep the venom from entering their blood system, thus protecting them. When a rattlesnake bites its prey, the prey animal dies, and the snake can swallow it whole. So, the venom ends up in the snake’s digestive system, but venom cannot get into the snake's blood from inside the stomach or intestines. But what if a snake bites itself? Usually, nothing dramatic happens, but sometimes it can be deadly. In other words, there's not a simple answer. Venomous snakes show a variety of different ways to protect themselves from their own bites. Some work better than others, and they work differently in different parts of their bodies. You know how curious scientists are, right? Well, many scientists have studied this by, well… injecting snakes with their own venom. Ethical issues aside, scientists have learned a great deal about this. It turns out different snakes have many different types of venoms, with many different damaging effects (nerve damage, circulatory system damage, and local tissue damage… nasty stuff). Animal bodies, including humans, have all kinds of defenses to help prevent damage. Let’s think of these defenses as locks. They lock out the bad venom. Venoms contain substances that we can think of as keys to these locks. The keys unlock the defenses and cause harm. There are many types of locks, and many different keys. Each key works in some locks but not in others. It’s complex. Here’s an example: Neurotoxins are positively charged, so they’re attracted to negatively charged parts of receptor proteins on nerves. This way, they “unlock” the defenses of the nerves and cause damage. Well, some snakes protect themselves from their own neurotoxin by reversing the polarity of their own nerve receptors. So, their positively charged neuroreceptors repel their own positively charged toxins, thus protecting them from their own venom. Cool, huh? But this is only one example of a gazillion different locks and keys. So, sometimes, a snake can seriously harm or even kill itself by biting its own body. Also, different individual snakes of the same species can have variations in their locks and keys, which is why, in one 1932 study, scientists made a couple of black-tailed rattlesnakes bite each other, and both snakes died as a result. Usually, though, if a venomous snake accidentally bites itself, it can relax and casually slither away, saying, “I meant to do that.” Below is a venomous eyelash viper Trish and I found in Costa Rica. 
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Trish and I recently enjoyed a week of hiking and exploring Arizona, particularly the Sonoran Desert. When I was on a solo hike in the 23,000-acre swath of public land at Lake Pleasant north of Phoenix, I kept hearing a loud braying sound coming from the far side of a cactus-covered hill. I had heard that wild burros lived in the area, so I kept an eye on the ridge at the top of the hill, and one of the creatures soon appeared. As it stared back at me from high above, I took some photos. The "wild" burros are awesome, and I was thrilled to see them. These burros are rather famous creatures in Arizona. But I think it's important that we understand exactly what they are and where they came from (the same can be said for "wild" horses). First of all, the word "wild" usually refers to native animals. Wild burros (and horses) are not native to North America. Yeah, I know horses evolved here millions of years ago, But—after some of them migrated to Eurasia over the Bering Land Bridge—they went extinct here along with much of the other megafauna 10,000 to 12,000 years ago. Burros, on the other hand, evolved originally in Africa. So, these "wild" burros are actually "feral" burros (and the same could be said for "wild" horses, which are descended from escaped domesticated horses brought here by Spanish explorers in the 1500s). The word "feral" refers to domesticated animals that have returned to the wild (after escaping or being released). The word "invasive" refers to non-native wild animals (not domesticated) that are now living where they don't belong and are doing environmental damage to the place they currently live. So are wild burros (and horses) invasive? They do actually damage the environments where they live, particularly when they get overpopulated (trampling, soil erosion, fouling the water, and competition with native wildlife). But this is where things get tricky. You see, people happen to LIKE burros (and horses). We think they're cute, beautiful, or whatever. This makes a big difference because activists form organizations to protect these particular feral species, even though the creatures are actually damaging to the environment. Near Lake Pleasant, there is a 103,000-acre area called the Lake Pleasant Herd Management Area. Yes, biologists regularly cull the herd to keep the burros from getting too overpopulated, but they still allow them to live there. Why? Because people like the burros. I doubt you'll find a lot of people campaigning to save the feral Burmese pythons in Florida. Oh... the amazing power of cuteness! Where did the wild burros come from in the first place? This species originated in Africa. As with horses, domesticated burros were introduced to the Desert Southwest of the US by Spanish explorers in the 1500s. Many of the burros in Arizona are descendants of a group of burros brought by Jesuit priest Padre Eusebion Kino to a Spanish mission near Tucson. Burros were heavily used by prospectors as pack animals during the gold rush all the way through the 1800s. Obviously, some burros escaped or were released. And because they are well adapted to desert conditions, they formed breeding populations that still thrive today. Unlike horses, wild burros do not display band or herd behavior. Instead, individual males (jacks) establish territories around a water source, and the only stable groups are females (jennies) and their foals. This is because of the scarcity of water, both in their native African habitat and in the desert southwest US. In areas where there is a lot of water, burros form larger harem groups, as horses do. There you go... more burro facts than you ever wanted to know!  Life's Great Mysteries - Wild carrots are not orange, so why are domestic carrots orange?12/17/2025 Wild carrots grow in abundance around here (in Missouri). The plant is also called Queen Anne’s lace, so perhaps you’ve heard of it or seen it along roadsides or in fields. When you pull up a wild carrot, the root (or carrot) is white or pale yellow. Let’s go back in time to examine this. Almost 5,000 years ago, people of the Persian Plateau area (today this area is Iran, Afghanistan, and parts of Pakistan west of the Indus River) first started domesticating the wild carrot, and the roots changed from white and pale yellow to purple and brighter yellow. Domesticated carrots then gradually spread to other areas. It wasn’t until the 1500s when, in the Netherlands, orange carrots appeared and became popular. The first carrots with an orange hue were, of course, a result of one or more random mutations. People decided they liked the orange color, and they bred carrots selectively for even brighter orange colors. During the 1500s, the Dutch were leaders in agriculture in the area, and the orange carrots happened to grow well in the Dutch soil and climates, better than the purple and yellow varieties. Dutch merchants then sold these robust orange carrots across Europe, and orange carrots became the favorite and the norm. Okay, this is where folklore begins. Sometime later, the Netherlands selected orange as their official national color, which was derived from the House of Orange-Nassau (also known as the House of Orange), which played a central role in the government of the Netherlands. The name comes from the principality of Orange, a Dutch territory that used to be situated in the south of France. Well, the Dutch began using orange carrots to promote the nation’s national color. And at some point, a folktale arose, which stated that Dutch farmers intentionally began selectively breeding carrots to be orange in honor of William, Prince of Orange. William was a leader during the Dutch Revolt, which began in 1566 and eventually led to the Dutch Republic. Is the story true? Nope, probably not. Here’s a quote from John Stolarczyk, curator of the World Carrot Museum (seriously). “There is no documentary evidence that the Dutch invented orange carrots to honor their royal family.” Now you know the story of orange carrots. Below are wild carrots (Queen Anne's lace) and domesticated orange carrots.  About two years ago, a strong wind toppled this massive oak tree near our garden. The tree fell in the forest (no, I wasn't there to hear it, so I don't know if it actually made a noise). The tree did not fall across a trail or on the garden, so we left it alone for the forest to reclaim. Until recently, there was little obvious evidence of decomposition. In October, I walked by it and saw that the tree was covered by the fruiting bodies of this fungus, which I'm pretty sure is called false turkey tail (Stereum ostrea). Of course, this fungus was growing inside the dead tree, digesting the wood, long before these fruiting bodies appeared. Typically, the main body of a fungus consists of a network of long, hair-like filaments called the mycelium. These thin cells secrete chemicals that break down the tree, and then the mycelium absorbs the nutrients. Obviously, this fungus has had time to grow throughout the entire tree. This process is what rots (or decomposes) the wood. When it is time for the fungus to reproduce, some of the threads grow toward the outside of the wood, and they form these "fruiting bodies" on the surface. Spores form on the lower sides of these fruiting bodies and are dispersed by the wind. Spores are usually one cell, capable of growing into a new fungus (new mycelia) if it lands in a spot that is hospitable for growth. Fungi are not the only things that decompose dead trees. Bacteria also do their part, as well as insects, worms, and other small invertebrates. In fact, a dead tree becomes an entire mini ecosystem, not only providing food for these things, but also providing shelter for countless insects, snakes, lizards, rodents, and even birds and bats. A healthy, diverse forest must have numerous rotting trees to provide habitat for all this wildlife. Removing dead trees from a forest breaks this cycle of life. The third photo is a rotting log we found in the Quinault Rainforest in Washington state.    Photos - Stan C. Smith Trish and I recently enjoyed a week exploring and hiking in the Sonoran Desert of southern Arizona. Here are a few photos of some really cool animals that are well adapted to desert life. First photo, the greater roadrunner. We only saw one of these, and this was the best photo I could get... because these birds apparently do not like to stand still! They are always darting this way and that, looking for prey animals (scorpions, lizards, insects, frogs, and even snakes). Roadrunners (in the cuckoo family) tend to not fly. And why should they? They hunt on the ground, and they can run at 15 to 20 miles per hour (24-32 km/h). The long tail helps balance them when they run. Sometimes, roadrunners will team up to kill and eat fairly large rattlesnakes. Two or more of the birds will relentlessly peck at the snake's head until it dies, then the birds consume the snake by tearing off bite-sized chunks. Well adapted to desert environments, Roadrunners do not have to drink water. They get all the water they need from the bodies of the animals they eat. Meep-meep. Actually, the roadrunner's real call is more of a woot-woot-woot instead of the meep-meep sound we all know from the cartoon. The second photo is another iconic desert bird, the Gambel's quail. These chunky birds are fairly common, and they run around in groups (called coveys), constantly making a loud and very distinctive call that sounds like "ka-KAA-ka-ka." I got to where I recognized the call and then I would try to spot the covey somewhere on the ground. Gambel's quail chicks eat mostly insects, and they transition to eating seeds and leaves as they mature. Like with the roadrunner, these birds get their water from the food they eat. When it is almost time for the eggs to hatch, the young actively call to each other from inside the eggs. At the right time, the mother calls to the unhatched chicks, triggering them all to hatch simultaneously. Cool, huh? Third photo, a curve-billed thrasher (on a buckhorn cholla cactus). These birds often nest and feed in cactus plants. The long, curved bill helps them pluck insects from the cactus without harming themselves on the spines. The long beak also protects them as they subdue potentially harmful prey like scorpions. Fourth photo, a ladder-backed woodpecker (also on a buckhorn cholla). Another bird that likes to live and feed in cactus plants. In fact, they used to be called the cactus woodpecker. Fifth photo, a side-blotched lizard. These lizards are unique because the males have a weird form of polymorphism—there are three different distinct throat colors in the males, and all three have different methods of getting mates. The orange-throated males are the largest and most dominant, and they keep a harem of females in a large territory. The blue-throated males are smaller, and they defend a much smaller territory with only one female. The yellow-throated males are "sneakers." They don't have a territory at all. Instead, they have coloration that mimics a sexually mature female, and they sneak around and use their disguise to approach and mate with unguarded females in the territories of orange throated males. Pretty amazing, right? Sixth photo, possibly a southwestern fence lizard. Arizona has a variety of similar lizards, so this is my best guess.       Photos - by Stan C. Smith Hey, you know how my mind works... every mystery, no matter how odd, is worth contemplating. This is an important question! Occasionally, I run out of underwear. Especially if I have just packed a bunch of them for a trip. It happens. So, what’s the ideal number? When considering this, I thought maybe the number should be different for men and women, then I decided there was no reason to assume such a thing. I searched far and wide for a definitive answer. Almost universally, the sources I found recommended that people have about twenty-five to thirty pairs of underwear. For the average person, this is enough to make sure you never run out. However, every person is different. So, I found a formula for calculating the best number of underwear specifically for you. As a service to humankind, I offer my optimized version of this formula (you're welcome): Step 1: How often do you wash your underwear? I actually found a survey of 2,790 men and women about how often they wash their underwear. 64% of men and 68% of women wear their underwear once before washing. Okay, cool. They also found that 22% of men and 18% of women wear their underwear twice before washing them. And… (drum roll) 5% of men and 7% of women wear their underwear at least FIVE times before washing. Most of those (about 75%) turn them inside out each time they put them back on. Anyway, let’s assume you wear yours once, and you do laundry once per week. This means you need at least seven pairs. Step 2: Add underwear for exercise. Let’s assume you wear a fresh pair of underwear whenever you exercise. If you exercise five days a week, add five more pairs. That puts you at twelve pairs. Step 3: Calculate in extra underwear that are your favorites for different outfits and activities. Different undies for different situations, right? This might apply more to women than men, due to the fact that women have more types of outfits to choose from. But maybe not… I have my special lucky underwear for when I go fishing. Let’s say you have three different types of underwear suitable for specific types of situations. Depending on how often those situations occur, add to your number. For this example, let’s add five pairs. This puts you at seventeen pairs. Step 4: Do you go on long trips? If you sometimes go on trips that last three weeks or longer, where you cannot do laundry, add another five pairs, putting you at twenty-two pairs. Step 5: Add another five pairs just for good measure. Your washing machine could break down. You might get really motivated to do two workouts per day. Whatever. This puts you at twenty-seven pairs. See? Those original estimates of twenty-five to thirty pairs were spot on. If you have fewer, you may want to grab some more next time you’re shopping. If you have fifty or sixty pairs already, well, you may have an obsession.  Trish and I recently returned from a week of exploring and hiking the desert areas of Arizona, particularly the Sonoran Desert in the area north of Phoenix. One of my goals was to find a rattlesnake. Well, while on a four-mile solo hike, I was walking beside a vertical rocky bluff, and there was this beautiful snake sunning itself in this nook in the rocks at about the height of my chin. Which gave me a perfect opportunity to photograph it (which I did for at least ten minutes). This is a western diamondback rattlesnake, the largest of the western rattlesnakes. These snakes are often nocturnal, so I feel lucky to have found one. I suppose it helped that this was November when it is much cooler in the Sonoran Desert than during the summer months. Although you cannot see it in these photos, western diamondback rattlesnakes have a distinctive series of black and white bands around the last few inches of their tail, leading to the rattles at the tip. Because of this, diamondbacks are sometimes called coon-tail rattlesnakes. Western diamondbacks have a reputation for being aggressive and rather dangerous. However, unless you try to handle them, accidentally step on them, or threaten them, they will leave you alone. After I photographed this snake for about ten minutes, it got a bit nervous and crawled into the dark hole at the back of this nook and out of sight. About an hour later, when I passed by the same spot again on my way back, it had come back out, giving me another opportunity for photos in a different pose. 95% of a diamondback's prey are small mammals, including prairie dogs, kangaroo rats, pocket gophers, voles, woodrats, and others. The other 5% includes such critters as birds, lizards, and sometimes even fish. Astoundingly, these snakes can go up to two years between meals in the wild. I kid you not... two years. Normally, though, when food is abundant, they eat once every two to three weeks. Although some people hate and fear these snakes, western diamondbacks are important to the desert ecosystem, serving as an important predator of small mammals and as an important prey species for larger predators such as coyotes, foxes, hawks, and owls. In other words, these snakes are part of nature and should be respected and admired (from a safe distance, of course).    Photos - by Stan C. Smith |
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