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Deviant Snake Skin Patterns

Hi friends, 

For many years I’ve been pondering and puzzling about the interesting deviations in the patterns on these snake skins. It has stimulated lots of creative thoughts and speculation about ecology, embryology, and evolution, as well as insights into the will of the creator. Your comments, insights, and suggestions are welcome. This is herpetologically geeky I admit, but fun to think about.

The venomous copperhead snake (Agkistrodon contortrix) is a master at camouflage.

Closeup of a copperhead snake's head

Below is a photocopy of the skins of six unfortunate copperheads. They are arranged in a progression — from the most orderly pattern on the left to the most “free-form” on the right.

Here are some of my attempts to articulate my thoughts and questions about what I see:

#1

 #1 is an example of the “standard edition” basic, unmodified  design.  Consistent “hourglass-shaped crossbands with dark margins and pale lateral centers”. (As herpetology text, Reptiles of N.C., states.)  Because of these pale centers on the sides of the snake (where the crossband pattern meets the belly pattern) they appear like dark x’s when the snake’s hide is stretched out flat.

#2

#2 shows the same basic pattern repeated down the snake except for what seems like an irregularity on the right side (after the fourth “X from the top).  Doesn’t it appear that these crossbands are created as separate halves that are “supposed” to meet in the center over the vertebrae but sometimes the “design production teams” in charge of producing and spacing their half of the crossband patterns get out of sync with each other.  In this one the right side has an extra crossband pattern half which “caused” a misalignment of the one above and two below.


On #3 it is the right side again with an extra pattern half in two places.

#3

#4 The two halves on #4 don’t meet at all in the upper mid-section. Is that “caused by” the extra pattern half on the left side down further?

#5 Some of the crossbands on #5 become abstracted to where they are barely recognizable as hour glass- or X-shaped

#6 More so on #6

#4

A copperhead snake skin

#5

Copperhead snake skin laid out flat with significant deviations in the pattern

#6

A copperhead snake skin with coloration pattern severely disrupted.

It looks like there’s a basic plan, theme, program, or “intelligent design” that allows a certain amount of variation. One of the purposes of these patterns is camouflage, to break up the outline of the snake. So, too big an unvariegated space = heightened visibility = death (and those genes are out of the pool).

I am told that the word that deals with these issues is “stochastic”—“denoting the process of selecting from among a group of theoretically possible alternatives those elements or factors whose combination will most closely approximate a desired result.” (Funk and Wagnall’s Dictionary)

But why the pattern sometimes seems to split along the spine might come down to embryology. As an embryo begins to develop the skin is formed during a process called neurulation where the neural plate folds to form the neural tube and the two parts with the epidermis meet at the dorsal ridge. This link shows it:

https://en.wikipedia.org/wiki/Neural_tube#/media/File:Neural_crest.svg

In reptiles and amphibians, there are three types of colored cells–melanophores (black/brown), xanthophores (yellowish), and iridophores (reflective). Together these are called the “dermal chromatophore unit”. As the neural tube curls, these cells migrate. There must be some kind of genetic instructions about where they should end up.

I’m thinking that as the two sides come together, the two halves of the crossbands reach across to join over the dorsal ridge and then somehow adjust to “fudge” when they don’t meet up. That’s as far as I’ve gotten with this so far. I’m open to any comments, clarifications, corrections, or suggestions.

Meanwhile check out this John Muir quote:

“When a page is written over but once it may be easily read; but if it be written over and over with characters of every size and style, it soon becomes unreadable, although not a single confused meaningless mark or thought may occur among all the written characters to mar its perfection. Our limited powers are similarly perplexed and over taxed in reading the inexhaustible pages of nature, for they are written in characters of every size and color, sentences composed of sentences, every part of a character a sentence. There is not a fragment in all nature, for every relative fragment of one thing is a full harmonious unit in itself. All together form one grand palimpsest of the world.”

– 1867 John Muir (Thousand Mile Walk to the Gulf)

 (Palimpsest–A parchment, manuscript, etc. written upon two or three times, the earlier writing having been wholly or partially erased to make room for the next. [Greek, palimpsestos, lit., scraped again]) Early paper recycling!

Thanks to Emily Lutkin for coloring the photo-copy of the snake skins.

Epilogue:

Check out the pattern on this copperhead!

Contemplating the will (and the methods) of the creator…
Bilaterally symmetrically (sorta) yours, Doug

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Three Snakes in One – Blacksnake-ology 101

… (including one astounding, but visceral, photo)
There are two kinds of common black snakes found in most of the eastern half of North America: the black rat snake and the black racer. Neither is venomous. The black rat snake is glossy black on top with a blotchy white pattern on the underside.
These are the ones that you find lounging around in trees, barns, and chicken houses where they ambush mice, rats, and other warm-blooded creatures. (Yes, they also like eggs and young chicks.)
Black rat snakes, especially the large ones, tend to be mellow and will often accept gentle handling by humans.
The black racer, or blacksnake, is a duller almost grayish black with a brownish nose and only a small patch of white under the chin.
It has a different personality entirely.  It is high strung and crawls amazingly fast. If you do actually catch one, they are usually very defensive. They tend to bite repeatedly and if you persist in holding on you may get a bit scratched and bloody. They are often seen on warm days racing through the thickets and creeks in pursuit of lizards, frogs, and other snakes–which brings me to the reason I’m writing this.  Our son Todd called us out to the road during this last warm spell, saying, “You gotta see this!”  It was a sad, but amazing road-kill: a freshly squashed black racer revealing three species of snakes that it had just eaten—a worm snake, a garter snake, and a northern water snake.
It reminds me of the time my friend John Connors came upon a black racer that had swallowed something so large it could hardly move. After a bit of gentle prodding the snake disgorged a good-sized copperhead.
I guess a black snake is good to have around!

Pick up my DVD with my story of the snake and the egg at a SALE PRICE!

While we are talking snakes, I might mention my one and only DVD  An Evening with Doug Elliott has almost an hour and a half of my favorite “Stories, Songs and Lore Celebrating The Natural World” includes my somewhat famous true story of the snake and the egg. This DVD just won a national Storytelling World award and we are celebrating with a half price sale—only $10 til the end of April 2012.  Check out the rest of the selection of books and recordings while you are on my website.
Enjoy the spring season. ~ Doug

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Australian Adventure

We spent the holidays in the land of bouncing kangaroos, screaming cockatoos, crimson parrots and eucalyptus trees (600+ species of eucs)! Our son Todd and his wife Kelsey were wonderful tour guides, treating us like royalty. Todd’s in grad school studying dispersal of fungi by vertebrates. We met various friends and mentors and checked out various national parks in temperate areas of New South Wales (called the New England high country)—even some rainforests.

Folks in Australia drive on the left side of the road, and many are hesitant about driving after dark because of the risk of a kangaroo bouncing through your windshield. Many cars have rugged metal bumpers called “roo guards.” Towns have very few stop signs—at crossroads they generally have a triangular yield sign that says “give way,” meaning you don’t have the right of way but you don’t have to come to a full stop. (I think about all the traffic tickets I wouldn’t have had to pay.)

It does seem strange to have Christmas around the summer solstice. Todd was pointing out a June bug to one of his friends and they replied, “That’s not a June bug; that’s a Christmas beetle!” They speak English, but there are a lot of terms that are different. Elevators are called “lifts”. Chickens are called “chooks.” In the city, ibises are called “bin-chooks” because they’re often seen rummaging around in trash bins. (Maybe they would be a good totem animal for dumpster divers!) Hiking is called “bush- walking.” Trails are “tracks.” Crawfish are called “yabbies.” Pickup trucks are called “utes.” Pastures are “paddocks.” Our favorite expression so far: Someone was talking about a rare animal; she said, “They are rarer than rocking horse shit.”

My favorite critter so far has been the foot long, half pound+ lizard called the blue tongue skink. It’s thick- bodied and rather sluggish and defends itself by opening its large mouth and sticking out its blue tongue and waving it at you.

I’m dreaming of a surreal Christmas…
We became aware of another interesting critter when Yanna noticed a big, oozing bloodstain on her pants leg. She had just had a visitation by a terrestrial leech. When a leech bites, it injects an anti-coagulant so the tiny wound keeps bleeding. The leeches are almost 2 inches long when stretched out. In one forest we explored, if you stopped for a little while you could see the leeches humping along toward you like a horde of thin, slimy inchworms. One of our friends saw one on my arm. She just rolled it up and flicked it away, “like a ball of snot,” she said. Any way you look at it, leeches really suck!

I’m dreaming of a surreal Christmas…

At least the parrots are red
and green!

The carpet python is the most dramatic snake we’ve seen. There were several of them hanging around one of the places we visited for a New Year’s gathering. One of them was 7 feet long, and it created quite a scene when it was discovered hanging out in the outhouse. It’s non-venomous and was delightfully easy to handle. Australia has a lot of snakes and many of them are venomous. We’ve seen a red- bellied black snake and a tiger snake—both venomous. We didn’t mess with them!

We’ve seen a couple of bowers made by bowerbirds. When mating season approaches, the male bird builds a “bower” (a runway/platform with two sides made of vertical grasses and thin twigs). Then he collects various objects to decorate his bower. When he gets his decorations in order and attracts the attention of the female, he does a little dance and shows off his treasures.

In the case of the satin bowerbird, he really prefers blue objects—one of the bowers we saw had blue flowers, blue parrot feathers, bottle caps, and lots of blue plastic clothespins. Todd had been watching this particular bower for several years. When he first saw it in 2010, the bower was just beginning to be constructed and all that was there was a blue sheep ear tag and a few blue-colored blewit mushrooms. That was when he realized that even birds collecting ornamentation for their bowers can in fact affect the distribution of mushrooms. He wrote a scientific paper about this and it got published in the journal, Australasian Zoologist. ( Look for it at your favorite news stand 🙂

Shortly after midnight on New Years Eve, a brushtail possum came to visit. What a nice way to start the new year!

Bound for Carolina: A Musical Journey Celebrating the Plants, Animals and People of the Southeast

Album cover for Doug Elliott's Bound for Carolina

This recording is also available for sale as a digital download at Bandcamp.

From Oh Susanna to Old Joe Clark, from the crawdad hole to the railroad yard, harmonica wizard, naturalist and storyteller Doug Elliott wails on his harp and sings a collection of blues, contemporary, traditional, and old-time songs celebrating country life, the natural world, and especially the people, the plants, the critters, and the rich environment and culture of southeastern North America. Elliott is accompanied by fiddles, guitars, banjos, mandolins, bass, drums, buckets, bottles, rattlesnake rattles, frog croaks and even a few blue yodels. This all-music recording features seven newly recorded songs as well as 14 favorites from previous albums. Special guests on this project include, Phil and Gay Johnson, Billy Jonas, Wayne Erbsen, and Todd Elliott.

Featured tunes:
Oh Susanna • Froggie Went a’ Courting • Big Black Snake • Rattlesnaking Papa • Old Joe Clark • Strawberry Picking • Dandelions • Creasy Greens • Root Blues • Crawdad Hole • Mole in the Ground • Bullfrogs on Your Mind • Bulldog on the Bank • Cluck O’ Hen • Who Broke the Lock • Ain’t No Bugs on Me • Sail On Honeybee • Bile them Cabbage • Left Hind Leg of a Rabbit • West Virginia • All Around the Water Tank