The Daily Bucket is a regular series from the Backyard Science group. Here we talk about Mother Nature in all her glory, especially the parts that live nearby. So let us know (as close as you are comfortable) where you are and what's going on around you. What's the weather like? Seen any interesting plants, bugs or critters? Are there birds at your feeders? Deer, foxes or peahens in your yard? Seen any cool rocks or geological features? Post your observations and notes here. And photos. We like lots of photos. :)OK, so Indiana Jones isn't alone--most people don't like snakes . . . though nobody is born with a fear of snakes--people are TAUGHT to be afraid of them. I used to make my living doing educational reptile shows for school classes (I've kept about 100 different species of herps and invertebrates, including venomous), and I can attest that little kids are universally fascinated by them. The bright colors, the fluid legless motion, the unblinking eyes--kids are drawn irresistably to them.
Some factoids about snakes:
There are about 2700 species of snakes living today.
Snakes are evolutionary descendants of lizards. More specifically, they are closely related to the giant marine mososaurs that lived during the time of the dinosaurs. Their closest living relatives today are the monitor lizards. There is some controversy over whether snakes lost their legs because they took up a burrowing lifestyle, or because they took up a marine swimming lifestyle--most scientists accept the "burrowing" hypothesis.
Snakes are not slimy. Their skin is smooth and dry, and is made from a protein called "keratin", which is the same thing human fingernails are made from. So a snake's skin looks wet and shiny, just like your fingernails. The "scales" are not separate structures like fish scales, but are made from thickened segments of skin--so the skin is all one piece.
Snake skin is dead and can't grow. Every few months, the snake rubs its face on rocks to split its old skin open, and crawls out of it like a sock. Because of this, many ancient religions worshiped the snake as a symbol of rebirth.
Only about one-fifth of all snakes are venomous and have fangs, and only 40 or so species are dangerous to humans. In the US, nearly all snake bites are the result of humans doing something dumb (like trying to tease, capture or kill the snake)--and over half of all snakebites involve alcohol.
The snake has muscular control over how much venom it injects, and about half the time when a snake bites defensively it doesn't inject any venom at all--a phenomenon known as a "dry bite". The primary purpose of venom is to kill and pre-digest prey, so snakes don't like to waste it on a defensive bite unless they have to.
Even if venom is injected, most untreated snakebites have less than a 30% death rate in humans. With antivenom treatment, the death rate is less than 1%. Most deaths from snakebite happen in undeveloped areas where there is no nearby medical treatment.
The longest modern snake is the Reticulated Python, which can reach 33 feet. The heaviest modern snake is the Green Anaconda, which can weigh over 400 pounds. The largest snake ever is the extinct Titanoboa, which measured 50 feet long and weighed about 2,000 pounds.
Snakes have only one functional lung. Male snakes have only one testis, but have two penises, one on each side.
A snake's digestive tract, urinary tract, and reproductive tract all empty out into a common chamber called the "cloaca". Snakes do not excrete liquid urine, but produce a white semi-solid glop similar to a bird dropping.
Snakes smell with their tongue. Their flicking tongue picks up scent molecules in the air, which it then inserts into a sensory pit in the roof of its mouth called a Jacobson's Organ.
The bones in a snake's skull and jaws are connected to each other by stretchy ligaments, like rubber bands. This allows snakes to swallow prey whole that is up to three times their own diameter. All of a snake's teeth, including fangs, are constantly being shed and regrown.
Snakes do not "walk with their ribs"--they use special muscles attached to their ribs to move the large rectangular scales on their bellies, which catch on irregularities in the ground to move the snake forward. Snakes cannot crawl backwards. To move quickly, they throw their body into waves which catch the ground and push them forward--it's the same motion they use when swimming.
Most snakes lay eggs, but many give birth to live young. The common Garter Snake even has a primitive placenta, which provides nourishment to the young from the mother's bloodstream before they are born.
Whenever I travel anywhere, I always head straight for the local zoo and the reptile house. So here are some photos of snakes that I've taken:
My current pet snake, Callisto. She is a Red Rat Snake, also known as a Corn Snake. She is about 4.5 feet long and is about 15 years old. She was captive-bred and has been around humans all her life, and she is puppy-dog tame.
Black Racer in the wild. St Petersburg, Florida. Since racers are active during the day, they are the most commonly-seen snake in Florida.
Green Tree Python. St Louis Zoo. They make their living by catching birds in mid-air, so although they are nonvenomous, they have extraordinary long teeth to pierce feathers and get a good grip.
Eastern Diamondback Rattlesnake. St Louis Zoo. At a length of eight feet, Eastern Diamondbacks are one of the largest snakes in the US.
Smooth-Scaled Green Snake, Lincoln Park Zoo, Chicago. One of the very few snakes that eats invertebrates like grasshoppers, crickets and spiders.
Aruba Island Rattlesnake, Lincoln Park Zoo, Chicago. Found only on the island of Aruba, in the Caribbean, it is one of the most critically endangered snakes in the world.
Boomslang. Pretoria Zoo, South Africa. A rear-fang snake, which has short fixed fangs at the back of its mouth. Its venom can be lethal.
African Rock Python. Pretoria Zoo, South Africa. The largest snake in Africa.
Mangrove Snake. Smithsonian National Zoo, DC. A rear-fanged snake. The venom is weak, so it is not particularly dangerous to humans.
Tentacled Snake. Smithsonian National Zoo, DC. This Southeast Asian snake is entirely aquatic and never leaves the water. It is rear-fanged and has a mild venom that paralyzes fish.
False Water Cobra. Smithsonian National Zoo, DC. Native to South America, it is not a member of the cobra family, though it can flatten its neck into a hood like a cobra. It is rear-fanged but has very weak venom.
Leaf-Nosed Rat Snake. Lowry Park Zoo, Tampa. This Vietnamese snake is also called the Rhinoceros Snake. It's not known what the horn on the nose is for.
Mangrove Salt Marsh Snake. Lowry Park Zoo, Tampa. One of the very few snakes that has adapted to salt water.
Eyelash Viper. Busch Gardens, Tampa. These small South American snakes come in two color phases, either mottled green and brown, or bright yellow.
Gaboon Viper. Busch Gardens, Tampa. The bright color pattern is cryptic, and camouflages the snake while it is lying on the forest floor. Although they are lethally venomous, the Gaboon viper is being captive-bred by private keepers.
And now it's your turn. Let us know what's going on in your neck of the woods. :)