Monday, December 9, 2013

Converting Ophidiophobes to Ophidiophiles, One Kid at a Time

"You study snakes? On purpose?? Why???"

I am a scientist. I lead a team of developing scientists (graduate students). One of the most important lessons to teach your graduate students is how to justify your research to the people who ask questions like this.

So we often find ourselves asking of the snakes: What's in it for us?



We can scream, "Biodiversity is important!" We can pontificate about the moral responsibility to respect all life. But the public wants to hear practical reasons why snakes are important.

Enter ecosystem services.

Ecosystem services is the idea that humans benefit from ecosystems and their myriad components. Obvious examples of ecosystem services of wildlife include honeybees that pollinate 100% of California's almond crop. Everybody loves almonds, so everybody (whether they know it or not) loves honeybees!

Honeybees pollinate many crops, including almonds. From http://ucanr.edu/blogs/bugsquad.

With snakes it is sometimes be a little harder. The classic go-to is this: Snakes eat mice, and keep their numbers under control. Without snakes, we could be overrun with mice.

A world without snakes might look something like this image from the 1979 film Nosferatu.

But there are a lot more ecosystem services provided by snakes. All you have to do is think outside the box a bit.

My hypothesis involves snakes and kids. When kids learn to love and appreciate snakes, it can have a dramatic and long-lasting positive impact on their attitudes toward nature and wildlife in general, promoting environmental stewardship.

I hypothesize that snake lovers grow up to be nature lovers, and all of nature benefits.

First, most people don't like snakes. Maybe even hate them. Definitely fear them.

Indiana Jones is a classic ophidiophobe. From Raiders of the Lost Ark (1981)

In fact, ophidiophobia (fear of snakes) is one of the most common animal phobias.

So how does this repulsion and fear develop? Is it innate, or is it learned? I have had lots of healthy arguments with people on this one.

From http://transformyourlifetoday.webs.com

Some argue that our sensitivity to snakes is innate. Lynne Isbell, an anthropologist at UC Davis, has proposed that certain neural and visual abilities of primates are the results of coevolution with venomous snakes. Basically, the idea is that the strong selective pressure to recognize a potentially deadly snake helped mold the neural connections between areas of the brain responsible for vision and for fear, learning, and memory.

From npr.org

Fascinatingly, some cognitive psychology research appears to support this idea. When presented with a collage of images and asked to find a target image (either snake, frog, caterpillar, or flower), people honed in on the snake way faster than any of the other three "non-threatening" stimuli. Even very young children located the snake more quickly. This suggests that visual and neural sensitivity to snakes may be innate.

Lobue and DeLouche. 2008. Psychological Science 19:284-89. doi: 10.1111/j.1467-9280.2008.02081.x

Side-note: A very enterprising advertising technique has emerged based on this study. One day last summer while checking the forecast on weather.com, my eyes were rapidly drawn to an advertisement at the bottom of the screen for lowermybills.com. The culprit for distracting me from my daydream of sunshine and a cool breeze? Snakes! The ad featured two sinewy serpents undulating across the banner.



Kudos to this ad agency for using cognitive psychology research to inform what is most likely to immediately draw people's eye. Now, as for whether most people would appreciate snakes crawling across their computer screen? That's another debate.

So maybe we have an innate ability to pick snakes out of a crowd. But is fear of snakes innate, or is it learned?

From http://fortressat.com

This is a question that has not been tested well. One study on ophidiophobes suggested that their fear was learned, but this was survey-based and can hardly distinguish between innate and learned.

In the absence of much scientific data, then, let's look at some qualitative evidence.

Samantha Brown, host of Cash Attack, meets a large python at Reptile Gardens in South Dakota. Photo retrieved from Samantha Brown's Facebook page.

The expression on her face reveals some of the emotions she is likely experiencing: fear and disgust chief among them.

But what about the kids? Look at those smiles!

I can tell you that the kid+snake=smile is practically universal. One of the pleasures of being a herpetologist is taking snakes and other reptiles to schools or hosting field trips where children get to meet snakes. With few exceptions, children are not afraid of snakes. Rather, they love snakes.

They are ophidiophiles.



So let's just assume for a while that fear of snakes is a learned phenomenon. Then love of snakes can be learned instead, if kids are exposed to snakes in the right setting. Where they learn about snakes in a positive light, rather than the sensationalist fear-mongering that goes on in so many Animal Planet shows and Hollywood movies.

Me showing off a rosy boa at a local school

I propose that kids who have positive, educational, hands-on experience with snakes become ophidiophiles, and that these ophidiophiles are more likely to make future life choices that benefit nature.

Snakes are a gateway drug for naturalists.

Ohio State graduate student Matt Holding introduces a young girl to a rattlesnake. This positive, safe experience with a snake could stimulate an appreciation of nature and wildlife in this child.

Holding a snake is not something easy to forget. I remember all the details of the first snake I held. That smooth black and white banded body, that tickly tongue. Birds? Mostly glimpses of tail feathers escaping into a bush. Mammals? The closest I could get was coyote poop on the trail in the morning.

But snakes? I got to hold them. That sunk deep.

Show a kid a picture of a beautiful animal, they'll say "Neat." Let them watch one through binoculars, they'll say "Wow." But let them hold one, and they might not say anything at all. They will be spellbound, smiles cracking their faces open. It changes their lives.

An ophidiophile in the making

They might go home and ask their parents for a pet snake. They might start catching garter snakes in the creek. They might pay lots of attention in high school biology so they can learn more about snakes.

They might become biologists and inspire countless future kids to love nature.

They might not. They might become accountants. But those accountants will be nature lovers. Because they took the snake-drug as a kid. Snakes made them fall in love with nature.

They'll be more likely to make environmentally friendly choices. They'll keep the environment in mind when they vote. Their kids will be snake lovers, too, having grown up in a family that does not sensationalize snakes and contribute to learned phobias.

Maybe coevolving with venomous snakes made our vision more keen. Maybe communing with a snake as a child makes our mind more keen.

From http://www.p0ach.com

Now that is an ecosystem service.


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This post is part of a blog carnival in honor of the 2013 Year of the Snake. A blog carnival is the concept of a whole bunch of bloggers blogging on the same prompt on the same day. Our prompt is #SnakesatYourService, and focuses on the ecosystem services of snakes. Here are links to the other blogs:

Good Neighbors Make a Greater Impact by Melissa Amarello (Social Snakes, @SocialSnakes)

Brown Tree Snakes of Guam by Brian Barczyk (@SnakeBytesTV)

Ecology of Snake Sheds by Andrew Durso (Life is Short but Snakes are Long, @am_durso)

Pythons as Model Organisms by Heidi Smith Parker (www.natureafield.com; @heidikaydeidi )

Snakes and the Ecology of Fear by Bree Putman (Strike, Rattle, & Roll, @breeput)

When the Frogs Go, the Snakes Follow by Jodi Rowley (Australian Museum blogs, @jodirowley)

Madagascar Snake Ecology by Mark Scherz (The Travelling Taxonomist - @MarkScherz & markscherz.tumblr.com)

Kingsnakes Keep Copperheads in Check by David Steen (www.LivingAlongsideWildlife.com; @Alongsidewild)

Wednesday, July 3, 2013

Legendary Reptiles

(Guest post by Ashley Ventimiglia, a student in my spring 2013 herpetology class)

There has always been something magical and mysterious about reptiles. They occur throughout cultures in ancient stories and tales about creationism. The dueling images of good and evil always have some sort of connection to reptiles, especially when it comes to scary or evil depictions. However, in the lore of Asian and Middle Eastern cultures, reptiles are symbols of prosperity, wealth and power. Some are even considered good luck and even seen as gods of the elements. Through research of mythology, history and folklore I was able to compile anecdotes that reveal how various reptiles enlightened different cultures throughout the world. Their presence in legends inspires ceremony and indulges the engrained perspective in many of these cultures; and you can see why.

Egypt: Apep the Serpent-Devil

Sir Ernest Alfred Wallis Budge’s 1969 book surrounding gods and mythological theories in Egypt ca. 3000BC describes accounts of the spiritual role of reptiles: “The spirits which were always hostile or unfriendly towards man and were regarded by the Egyptians as evil spirits were identified with certain animals and reptiles…” He goes on to describe a great serpent-devil who was the arch nemesis of the sun god RA, whose name was Apep. This record of the enormous serpent was preserved and recently found to be more than just a theory. Found in Fayyum, the remains of such a serpent were discovered: “The vertebrae are said to indicate that the creature to which they belonged was longer than the largest python known." In the footnote, the longest known at the time the book was written was 30 feet. 


It seems that the serpents and reptiles of evil only held positions of evil power. Apep was said to be the conjurer of darkness, storm, and mist of the night, leading to the fear of all reptiles (but especially snakes) in early and modern day Egypt (Budge, 1969). There is also reference to “serpents of the underworld,” where heroes’ souls were ripped out by angels and carried down to hell on the backs of black horses. After this, the souls were thrown into 200 foot pits of snakes – “in this place were several other terrible serpents, and to one of these, which had teeth like iron stakes, the poor soul was given to be devoured; this monster crushed the soul for five days of each week, but on Saturday and Sunday it had respite." This to many historians hinted that the evil respected the Sabbath of the Jews and the Christian Sunday. These allusions to the great serpent of the Egyptian underworld are seen many times throughout historical documentation of the time, and are known by many names; always being the terror of those worshippers of the sun-god. And, being the well-known demons of hell and associated with evil spirits and bad omens, snakes were feared, killed, even repelled from the dead by Egyptians then and today.

Native American Lore and the Origins of Reptiles and Amphibians


The Egyptians may have seen reptiles as a source of fear and evil, but in Native American culture legends of the origins of reptiles gave a sense of inquiry and fascination about them. In 1852 a Christian chief named David Cusick of the North American tribe Tuscarora recorded a legend; he called it the legend of his people (Tylor, 1871). In this legend, there were two worlds – the lower world that was shroud in darkness and occupied by monsters and the upper world that resembled Earth and was occupied by mankind. The legend begins with a woman, later called the celestial mother, descending from the upper world to the lower world on the back of a tortoise who took with him some earth on his back. 


Once in the lower world, the tortoise becomes an island on which the woman gives birth to twin boys before dying. The boys were called Enigorio meaning “Good Mind,” and Enigonhahetgea meaning “Bad Mind,” and are the depiction of good and evil among Tuscarora religion. As the boys grew along with the tortoise island, Enigorio also grew wary of being in darkness and used his mother’s head to create the sun, her body to create the moon, and with her also created small balls of light, which became the stars. Enigonhahetgea, wishing to keep the dark world as it were, saw that the monsters of the dark disliked the light and hid in crevices so that the mankind of the upper world would not find them. Being spiteful of his brother’s creation of light, and later his creation of “real people” and mammal like creatures, Enigonhahetgea created obstacles for the beings of high mountains and waterfalls. Then Enigonhahetgae also created reptiles, which were injurious to mankind. Of course these legends were before the time it was actually written down, and were in fact the belief of the Tuscarora before the coming of Christian Europeans in the colonial era of North America.

In the Journal of American Folklore, Speck (1923) wrote an article entitled "Reptile Lore of the Northern Indians" where he speaks often of the Wabanaki and Penobscot Indian tribes and their herpetological myths. Speck describes numerous legends involving the origin of rattlesnakes, frogs, toads and turtles. The legends are short, but filled with lessons and characteristics akin to our reptilian counterparts. In one such Penobscot legend, a transformer by the name of Gluskabe came across a 
village full of Indians who danced so vigorously and so often that he turned them all to snakes. In a similar Wabanaki legend, the leader of such dance carried a rattle, which he used to accompany the songs of the dance. Because of the rattles’ presence, the dancers were transformed to rattlesnakes and thus were the origin of the species.


Another transformative legend of the Penobscot and Gluskabe is the “conquest of the monster frog,” in which Gluskabe becomes a hero and replenishes the world of its water supply after defeating a giant monster frog who held the water of all the world in its stomach (Speck, 1923). After returning the water to the thirsty human inhabitants of earth, some humans were so eager to get the water that they plunged in and turned to fish. Modern day frogs are said to be descendants of this monster frog and thus are treated with respect by the North American natives, and are also said to cause floods and drought when upset with their human servants.


Gluskabe returns in the legend of the origin of toads (Speck, 1923). Two beautiful girls apparently ridiculed Gluskabe while dancing at a ritual; this turned out to be a big mistake! The transformer turned the two girls to the most repulsive creates he could imagine, and thus emerged the toad. It seems as though we owe Gluskabe a lot when it comes to all of our herp species in North America, but man does the guy have issues! 

Speck describes his last and final folk tail in reference to the origin of turtles and tortoises, when Penobscot legend tells of a handsome suitor of the Auk (meaning bird) Chief’s daughter. The handsome suitor who lacked speed and sense of humor tried to win the daughter's hand by jumping over and clearing the top of the chief’s wigwam pole. The suitor fell short and impaled himself on the wigwam, where beneath was a roaring fire. The chief allowed the suitor to be scorched until he was encysted and cracked because of the heat – which is how the tortoise got his shell. Because the suitor was slow and lacked a humorous demeanor, the tortoise who is said to have the same characteristics according to the Penobscot tribe, originated from that suitor specifically.

The Ambivalent Bible 


Of course, there is the classic evil represented by the serpents in the Bible; however, surprising as it seems, not all serpents in the Bible represent evil. In the Book of Numbers, Moses is inculcated by God to erect a statue in the shape of a snake and put it on a pole (Murison, 1905; Stanley, 2008). According to the book, anyone who was bitten by a venomous snake and then traveled to look upon the pole would be saved. It was realized by and the comparison made by Jesus himself, that this was an allusion and an instance of foreshadowing - representing how Jesus was crucified on a pole for the sake of saving people (Murison, 1905; Stanley, 2008; Tenney, 1997). Several other references to the snake can be found in the Bible, with the snake representing wisdom, evil, and an agent of the vengeance for God (Stanley, 2008; Murison, 1905; Jeffrey, 1955). 


But the most well known is that of the serpent who tempted Eve in the Garden of Eden to eat of the forbidden fruit she was told by God never to consume. The serpent, who represented the devil and was under his influence, convinced Eve to eat the fruit, and she and Adam gained the knowledge of God. He then punished them by bestowing the pain of childbirth to Eve and the burden of working the land for resources no longer handed to him, to Adam. Although the serpent in most lore around the world is a representation of evil and death, it is refreshing to see also the representation of snakes as good omens as in the Book of Numbers.

Hinduism: In Celebration of Snakes 

In Hindu culture, snakes are revered and celebrated as being divine, representing gods, and are central symbols of Hindu holidays and ceremonies. In B.A. Gupte’s (1994) book Hindu Holidays and Ceremonials: With Dissertations on Origin, Folklore and Symbols, he explains the origin of the holidays and ceremonies through legends and anecdotes. From what I could gather, Nagas are cobra rattlesnakes, and in the Hindu religion they represent 9 powerful gods, one of which is the chief the Nagas (hooded cobras) named Ananat. Another is the deity of Bengal and presides over all the Nagas. There are several stories that Gupte describes surrounding how Nagas came to be celebrated and worshiped. The first tells the story of a daughter in law ordered to cook veal for her father in law - in order to make sure it was cooked and palatable, she asked a servant to taste it. The servant, being lowly, ate all of the veil; the girl then asked for the servant to replace it, who replaced it with flesh of a dead calf. The girl, unable to cook the flesh in time for dinner, asked to the servant to pour water on the floor, making the girl slip and drop the curry so that it could not be served. This fiasco caused the snake brooding under the house to give birth, and the reptilian litter emerged and undulated all about the house. Being frightened, the girl who had been holding a brass lamp dropped it and caused several of the baby snakes to lose their tales. Time passed until there came the month of Shravan, which is July-August. On the 5th of the month the girl drew snakes in a stool and began worshipping them, having felt bad for harming the snakes of the house. She prayed to the god of Nagas to protect her reptilian brothers, as she called them. On the same day, the young snakes asked their mother how they came to be deformed; their mother explained to them that the girl of the house had accidently dropped a lamp on them, causing them to lose their tales. Angry, the infant snakes found the girl and went inside of a body (I assume this means they embodied the form of a single snake collectively) in order to avenge their shame through biting her. Coming upon the girl, the snakes realized that she was praying to a stool of serpents and asking for protection over them. Now feeling guilty, the snakes waited until she had left before returning to their individual snake forms, and eating of the parched grain and milk set under the stool as offering. After receiving the offering, they left a jeweled necklace as a token of thanks and made the girl prosperous and happy. 


A second Hindu story specifically surrounding the deity Manasa from Gupte’s book on Hindu holidays and ceremonies explains another reason why snakes are revered. In this story, a rich man or Bania had seven married sons whose wives all brought gifts to his wife- all except the youngest of the daughters-in-law; the young girl was therefore disliked by the mother-in-law. One night while collecting water, the girl thought she saw fish in the pond and stowed some away in her pot. In the morning she was surprised to find her pot full of snakes that had escaped into her pot as a safe retreat from a forest fire the night before. The girl fed the snakes plantain meal and milk, after which the cobras felt much indebted to her. They asked the Goddess Manasa if the girl could be transcended to Manasa’s celestial palace and treated like a princess who would care for them. Manasa agreed and, after taking the form of a mortal and acting as the girls' maternal aunt, delivered the girl to the celestial palace where she was adorned in jewels and riches as long as she boiled milk for the cobras each morning and as long as she never looked South. Tempted one day, the mortal girl looked to the south and witnessed Manasa dancing, an uncommon practice for women of the time. Entranced by the movements, the girl forgot about the milk on the stove. When it was given to the hungry snakes for breakfast, they were scalded. Angry, the snakes threatened to swallow the girl whole until Manasa appeased them, promising to deliver her back to Earth since she always knew having a mortal in the celestial palace would be cause for error. However, since the Naga were known to be a vindictive species, she told the girl to praise the Naga to her people in order to appease them from harming mankind. The girl, still doused in the gifts of the Naga and their deity, was retuned to the Bania and told her mother-in-law of the generosity of the Naga. The Naga, who had secretly followed her, heard her praise them - the cobras adorned the mother-in-law and fellow daughters-in-laws with riches and jewels and they were happy. Manasa then told the family that rice, soaked overnight and made into Khichadi (which happened to be the youngest daughter-in-law’s favorite dish) would protect them from snakebites. After the goddess had gone, and the daughter relayed her stories of the Naga further, she became a favorite of the household. The neighbors adopted this worship of the Naga, and there is still a ceremony celebrated today in India with hopes of gaining good luck and avoiding harm from the Naga.


Because of legends like these, snakes are both feared and loved in India; “…thousands die every year of a snake bite, and there are millions in India who have sometime or other just escaped from being bitten. [But] A chat about snakes is as absorbing and as interesting and thrillgiving, as a tale about spirits, ghosts and thieves" (Lall, 2004). Many farmers avoid plowing their fields to keep from harming snakes, and during festivals people pay professional snake catchers, who have (allegedly) become immune to the venom, to catch cobras for rituals and worship. The festival of the Nagas called Nag Panchami is celebrated on the fifth day of July each summer, at the time of Shravan. At these festivals, cobras are offered milk and crystalized sugar in worship and hope not to get bitten in the year to come, as the legends convey (Sanford, 1988). Many stories surround these festivals, and the mystique of snakes collected for the ceremonies is embellished.

An eighty-year-old Hindu man told Lall (2004), the author of Among Hindus – A Study of Hindi 
Festivals, that the older snakes who remain undisturbed in the thick jungles of India have a manka, which is a precious stone stored in their heads. Late at night, the snake will eject the stone from the head via its mouth onto a clear patch of ground. The snake will dance around the stone, adoring its beauty in the night as it glows in the dark. Lall then goes on to describe how, after the snake is satisfied, it will pull the stone back into its head through its mouth where it is then encrusted like a jewel. The Hindu people often conjure up stories on how to capture these jewels.

Here There Be Dragons


Of course, no compilation of reptile lore can go without mention of dragons. Dragons have been the objects of fantasy and center of curiosity for many people throughout history and culture. According to Ingersol (1999), the avid writer of Dragons and Dragon Lore, dragon myth is mainly concentrated in China and probably originated there. Many who were interviewed by Ingersol believe that old bones and teeth of reptilian descent hold strong medicinal powers, as if they came from dragons. Much of the dragon lore surrounding Asian culture and other cultures embody a sense of evil and malice: large, flying reptiles breathing fire and terrorizing villages, stealing virgins and fighting brave knights with swords. 


However, one of the more prominent images and famous dragons in Chinese culture is a shen or god, and in this instance a rain-god. The Chinese people pray and worship an image of a long, serpent like dragon that covers himself with the water of five different colors (rainbow) and sprinkles the earth with water and fertility. According to an interviewed philosopher Kwang Chung who quotes the classic Kwan Tse, the five colors the dragon covers himself with means he is embellished with “cardinal virtues,” meaning that the dragon has the ability to shift his shape to go anywhere below, within, and above Earth (Ingersoll, 1999). 


The dragon then, is not limited by the space of time, and therefore can only be a shen (meaning god) by every definition of the Chinese word. The same dragon, in other ancient descriptions, is considered of the highest rank and therefore “imperial.” Being the embodiment of fertilization and controller of the waters of the earth, the dragon has the power to invoke and revoke the rain. Because of his powers, the Chinese in ancient times and today worship the reptilian rain-god, hoping for fertile land and no drought. Other depictions of dragons can be seen as controlling different forces of nature and the elements in Chinese art, conveying them to be different deities of those elements. 

Across the globe reptiles are among some of the most feared creatures in cultural lore. Many represent evil and malice. They are feared and avoided and sometimes killed because of these ancient legends. But, in many cultures reptiles (especially snakes) are celebrated and worshipped. Legends have a unique way of telling tales that reveal truth and give moral insight to how people should treat animals. In this case, legends are the stuff that drives respect for reptiles in every culture, be it through fear or superstition. But, I think we can all agree that there is something fantastical about reptiles that can only be conveyed through finding where they came from in stories, and that is what makes them legendary.


Sources:
Budge, E. A. W. 1969. The Gods of the Egyptians: Studies in Egyptian Mythology. Vol. 1. Courier Dover Publications.
Gupte, B. A. 1994. Hindu Holidays and Ceremonials: With Dissertations on Origin, Folklore
and Symbols. Asian Educational Services.
Ingersoll, E. 1999. Dragons and Dragon Lore. Book Tree.
Lall, R. 2004. Among the Hindus: A Study of Hindu Festivals. Asian Educational Services.
Sanford, A. W. 1988. Hinduism and Development. In: Handbook of Research on Development and Religion. Edward Elgar Publishing.
Murison, R. G. 1905. The serpent in the Old Testament. The American Journal of Semitic Languages and Literatures 21:115-130.
Speck, F. G. 1923. Reptile lore of the Northern Indians. The Journal Of American Folklore 36: 273-80.
Stanley, J. W. 2008. Snakes: Objects of Religion, Fear, and Myth. Self-published here
Tenney, M. C. 1997. John: the Gospel of Belief: an Analytic Study of the Text. Wm B. Eerdmans Publishing.
Tylor, E. B. 1871. Anamism. In: Primitive Culture: Researches into the Development of Mythology, Philosophy, Religion, Art, and Custom. Vol. 2. John Murray.

Sunday, December 2, 2012

The 250 lb. Hamburger


“…so when a snake eats its prey, it’s like if you were to eat a 250 lb. hamburger, all in one bite, without using your arms!”


It’s 1997, I’m an English major at UC Berkeley, and I’m sitting in a classroom in the palatial Valley Life Sciences Building. This is a building that English majors do not frequent. The shiny white pillars hurt our bookish eyes. Yet I keep coming back, week after week, to a classroom filled with big cat skulls, stuffed egrets, and pickled frogs. By some fluke I have enrolled in a class called Natural History of the Vertebrates, which has nothing to do with my major. It is here that I first witness the hamburger magic trick.

Fifteen years later, the magic trick is still fresh in my mind. And magic it is. Not the rabbit-in-the-top-hat, saw-your-assistant-in-half kind of magic, but real-life magic. Teaching magic.

Making an analogy that allows students to see something from their point of view.
Magic, like most things in life, works best when greasy food is involved.

In that classroom at UC Berkeley, and in countless classrooms before and since, Dr. Harry Greene used the hamburger trick to help students understand one of the most mind-boggling processes in nature: how a snake with a mouth the diameter of a walnut can ingest a rabbit the size of a football… all with no hands.


A Western Diamond-backed Rattlesnake eats a large rabbit. 
J. Schofer

The hamburger trick, friends, is the subject of this post.



So how in the heck does a snake pull off this feat? Let’s start with the meat of it all—or rather, the bones and ligaments.


First things first: it is important to come to terms with the fact that our human skulls are boring.

In contrast, a snake’s skull is a thing of beauty and complexity—by all accounts, an exemplary marriage of structure and function, a marvel of evolution.
The skull of a Gaboon viper boasts impressive two inch-long fangs.
m.inmagine.com


This post is an appetizer version of how-the-snake-skull-works. Keep in mind that I am greatly simplifying the following descriptions—another magicky thing us teachers try to do.

Here's how it works. Your jawbone (or mandible) is functionally a single bone. It articulates with your cranium in joints on either side, in front of your ears, that allow limited rotational movement of the jaw, allowing you to bite, chew, talk, etc.
"The last thing I remember, I was looking at a human skull in anatomy class. I must have died of boredom."

The setup is far more interesting in snakes. The jaw does not attach directly to the rest of the skull, but rather suspends from the skull via the quadrate bone. (You kinda have a quadrate bone, too, but it has migrated, over millions of generations, into your ear—a "hear bone.") 
The large quadrate bone in a reptile skull is shown at left. 
Wikipedia

So, think of it as snakes having their jaws suspended from the rest of the skull via a mobile quadrate bone. The snake's quadrate bones can basically whirl around on each side. This funky attachment makes the snake’s mouth far more flexible than yours, and also makes the opening larger.


An egg-eating snake routinely eats eggs several time the diameter of its own head. Notice how the skin stretches between the scale rows. Read this blog for more on egg-eating snakes.
B. Bouton

Still not a big enough hole for Peter Rabbit, though. The trick is in the joint at the front of the jaw bone. Your jaw actually consists of two bones (dentary bones) that fuse together at this joint when you’re a fetus. In a snake chin, the dentary bones are connected with a stretchy ligament that allows the two sides of the jaw to stretch away from each other, allowing the mouth to open even larger.



This image from Digimorph shows nicely how the two dentary bones of the lower jaw are not connected with bone.
You can see the two sides of the jaw stretched far apart in this image of a python gorging on a sheep.


The articulation of the quadrate bone plus the elastic ligament at the chin allow the python's mouth to open large enough to eat huge prey— like deer, crocs... even humans
lifeslittlemysteries.com


There’s much more to it than that—other moveable skull bones, super-stretchy skin, even a snorkel to help breathe while the maw is stuffed (yes, really!)—but I am hungry for a hamburger. 

(Note that snakes' jaws do not "unhinge" or "dislocate." Those are entrenched myths that arose from people trying to compare their jaws with our jaws. Let's keep it real, people.)
The upshot of the structural adaptations I have described above is that snakes can stretch open their mouths really wide—wide enough to ingest prey many times the diameter of their own head. Now we are ready for the main course:


“…so when a snake eats its prey, it’s like if you were to eat a 250 lb. hamburger, all in one bite, without using your arms!”


Sadie helps show us what a Macrostomatan Harry would look like sucking down a beast-sized burger. 
J. Furman

That’s a big burger. (A mere fraction of the world record burger, weighing in at a ton, but a big burger nonetheless.)


The record largest burger was made at a Minnesota casino in 2012. It had to be flipped with a crane. But I digress...
nydailynews.com



Now you can put it all together and watch Harry doing his magic here:


Abracadabra! That is how the magic is done.


Getting hungry? Eat like a snake.



Note: Harry Greene's book Tracks and Shadows: Natural History as Art came out in 2013. If you're still hungry, pick up this book (or his 1997 classic Snakes: The Evolution of Mystery in Nature) to read about some more amazing things snakes do!

Tuesday, November 27, 2012

Man-Eating Snakes

Snake architecture is superfically quite simple. Snakes are basically a long tube of muscle and gut, with a toothy mouth on one end and a pooper on the other.



This image can get pretty creepy when the snake is longer than a grown man and as big around as Mike Tyson's thighs. It turns out that the prospect of being eaten by something can drive a pretty strong evolutionary phobia. Some scientists even say that the reason our binocular vision is so acute is because of growing up with—evolutionarily speaking—big snakes that could eat you.


John Voight’s binocular vision couldn't save him from being eaten—then regurgitated and re-eaten—by a mammoth snakein the 1997 movie Anaconda.


Of course, anacondas don’t actually get that big. But they get plenty big. The anaconda—a denizen of swamps and rivers of Central and South America—is the world’s most massive snake, meaning it’s the heaviest but not the longest.





 

What can I say? Men in groups like to carry huge anacondas around.


Scientists debate the particulars, but the anaconda that takes the record was about 28 feet long, with a 44-inch circumference. What weight does that translate to? Probably about 500 pounds. Sheesh, that’d gobble up some serious human.

Of course, the majority of anacondas—even the biggest—content themselves on a diet of fish and wetland mammals, because these snacks are much more abundant than humans, and maybe also because anacondas prefer eau d’poisson over body odor. But could an anaconda occasionally eat a human?

Who better to ask this question to than Dr. Jesus Rivas, who has been studying anacondas in the wild for 20 years? 

Jesus Rivas examines a large female anaconda.
 
Rivas says that there are no documented cases of anacondas eating humans, but that might be partly because anacondas, especially the big ones, tend to live in remote areas with few humans. However, he describes two cases in which his field assistants have been stalkedunsuccessfully, phew!by their study animals. It was even caught on camera:

An anaconda stalks a scientist in the Venezuelan Llanos. www.anacondas.org



One thing is for certain: anacondas eat big stuff. Rivas has witnessed them eating white-tailed deer and crocodilians.  

An anaconda swallows a caiman.

If your interest in anacondas is piqued, Rivas has written a book on them, coming out in 2013. In this book, he shares an account in which he himself was stalked by a 15-foot anaconda affectionately named Lina. 

Rivas, J. A. 2013. Natural history of the green anaconda:  Two decades disentangling the secrets of the world’s largest snake. Oxford University Press.

In the meantime, check out this video of a large female anaconda puking up a cow!




If anacondas are the heaviest snakes, what are the longest? Reticulated pythons from Southeast Asia take that trophy, uncontested. The longest recorded “retic” is about 33 feet—yes, that’s five or six people laid end to end. Burmese pythons and African rock pythons can exceed lengths of 20 feet and are also quite formidable predators. These python species along with a few others star in the smorgasbord of online images of snakes eating large prey items.

A python has eaten a sheep.
A non-native Burmese python in the Florida Everglades ate an American alligator. The likely story is that the meal was too large and killed the snake, then scavengers noshed open the snake's belly.

A python kills a cow.



An olive python fixes to eat a wallaby.

But, do pythons eat humans? Let’s start with rock pythons, which—despite their penchant for eating lots of birds and non-human mammals—definitely have been known to occasionally include a human in the picnic basket.

Wikipedia cites a number of fatal attacks, in which a rock python killed a person but didn’t end up eating them. In at least two cases, the pre-teen prey was too large to get down the hatch; in another case a farmer was dragged up a tree by a python and rescued when he managed to call for help on his cell phone. In a few cases, however, the python managed to gulp down the prize: a 10 year-old was swallowed in 2002 in South Africa, and in the 1970’s a Portugese soldier was found inside the stomach of a snake.

A rock python has eaten a very large meal (not a human, however) and become stuck in a fence.

A close-up of the fenced snake, just for the awesomeness of it.

I asked Dr. Graham Alexander of The University of the Witwatersrand in South Africa to tell me about any close encounters he’s had with rock pythons during about eight years of studying them in the wild. Dr. Alexander said that the largest thing he ever witnessed a python eat was an impala, but that spending time in the wild with these huge snakes could be unnerving: 

“After tracking pythons for many years and not experiencing anything like a predatory attack, I felt pretty confident that they just didn’t do it (and I told many people that pythons don’t attack people). However, that all changed towards the end of 2010 when I was tracking both pythons and Puff Adders. I had about 30 telemetered snakes going at one time and tracking took all the day light hours – and I was often pretty rushed trying to get to all the snakes in a day. On three separate occasions in that season I was bitten on the leg by large female pythons that were lying in ambush. In these cases I had been pretty sloppy – moving in on the signal way too fast under time stress and probably with less caution than I should have – and accidently walked past the snake. My interpretation was that the pythons had struck and bitten me because they thought I was a meal. In only one of these cases did the python start trying to constrict, but even this one released me as soon as it realized that I was not an impala – or that’s how it seemed. In the other two cases, the python bit and released immediately without initiating constriction. In all three instances I was on my own and got the fright of my life. The bite comes out of nowhere and really does take you by surprise. I can really imagine what it is like for a real prey item. And that probably gives the snake a very large advantage.

I am afraid that those are the only experiences that could possibly be predatory attacks. I still think that we are not really on the menu of Southern African Pythons, though they do get pretty large and do consume meals of up to about 50 kg.”



A rock python has swallowed a prey item much larger than the width of its head.
Last but not least—let’s look into the maw of the star of the show, the retic.

Reticulated pythons, the longest species of snake alive, have munched on theirshare of people. Wikipedia lists a few instances of people being eaten by retics, some confirmed, some not: several people walking through the Malaysian bush got nabbed by 20+ foot pythons, including a Burmese jeweler in the early 1900’s who was eaten feet-first; plus a number of captive retics along with Burmese pythons have decided to eat their owners or their owners’ children.

The fact that it is the longest species alive today isn’t the only reason the reticulated python has notoriety among man-eating snakes. It holds the distinction of having had its man-eating tendencies studied thoroughly by an interdisciplinary team of scientists. A herpetologist (Harry Greene) got together with an anthropologist (Thomas Headland) and they found stuff out about man-eating snakes, stuff that neither would have been able to totally figure out on their own.  Awesome. 

Thomas N. Headland and Harry W. Greene. 2011. Hunter–gatherers and other primates as prey, predators, and competitors of snakes. Proceedings of the National Academy of Sciences of the USA 108:E1470-E1474. 

They studied the Agta Negritas, a tribe that was still pre-literate in the Philippines as of the 1970’s. The Agta hunted reticulated pythons for their meat, netting 25kg+ of meat per snake.





Agta Negrita hunters in the Philippines pose with a 20+ foot-long reticulated python in 1970.
But the hunter often became the hunted. From in-depth interviews with the Agta, the scientists discovered that large pythons had indeed tried (and sometimes succeeded) to eat tribe members. Over a period of time extending from the 1920’s through the 1970’s, the Agta reported 18 men that were unsuccessfully attacked by pythons, and six people that were killed by pythons.



So there you have it. Those are the records that we have of man-eating snakes in modern and ancient times. The numbers are small and the photos are few. 

This is the point where I should hear some of you calling bullshit. What’s that you say? You’ve seen photos online of giant snakes eating people?  


Take this photo of a large retic with a human-sized bulge captured in southeast Asia. Is this real?
Drumroll… Yes it is! But… that’s no human in the belly. This photo is often accompanied by the image below, allegedly showing the unlucky teenage boy cut from the snake’s guts.


A reticulated python has noshed a teenage boy… or has it really?


Except that the two snakes are clearly different animals. Whoops. I mean, who’s gonna notice a paltry detail like that when faced with a human body being cut from a snake’s stomach? 

Anyway, the question comes down to this: is this photo real? 

Killer photo opp. You can tell the photo is faked because the boy's body is not covered in digestive goo, but also because of the presence of the large bag or piece of fabric between the boy's head and the snake's guts. 
I'm not sure which is more awesome, thougha freshly ingested human body being cut from the belly of a retic, or a kid with enough cajones to stick his head and torso inside a dead snake's belly. 



I’ve saved the best for last. Here is a photo of one of the few allegedly real instances documented by photo in which a snake killed a human.


This unfortunate soul was killed by a reticulated python, but then the story goes that the meal was too big for the snake to take down—gobs of goo covered the man’s head but the snake couldn’t make it past his broad shoulders.

So, could it happen to you? I've always thought it would be an interesting way to die. But our chances of being eaten by a giant snake, even when wading through a flooded plain in Venezuela or spelunking in the Philippines, are lower than the chances of being struck by lightning at the exact same time as winning Mega Millions. 

Your chances might be a little higher if you encountered one of the beasts below coiled in the crook of an ancient swamp tree. At over 40 feet in length and weighing in at over a ton, Titanoboa—recreated by the awesome people at the Smithsonian—would definitely have noshed a few humans.

Smithsonian visitors view a scale model of Titanoboa.

Good thing for us that we didn’t evolve for another 55 million years.




Author's note: If you can identify the photographer of any of these photos, have information about them, or have a good story or photos of a man-eating snake, please let me know (snakeymama@hotmail.com). I will update the blog post with new information.