Wednesday, October 29, 2014

An Alien Visits a Freshman English Classroom - Juvenile Mediterranean House Gecko

Recently in the second floor classroom at Campbell University where my wife teaches freshman English classes, a college student noticed a small wild non-student tumbling about in a back corner of the room behind an audiovisual equipment cart. Together they shepherded the dust covered creature into an empty fast food drink cup.   They sent me these two pictures via text prior to my wife bringing the alien home.

Below is the little alien walking on the side of a Sonic drink cup.

Looking at its unique toes, it did not take long to identify this cute little reptile as a gecko.  Besides its toes, I noted its banded tail, the dark mottled spots on its tan skin, and in particular, the presence of many tubercles (wart-like bumps) covering its body.  I had not known that there were geckos living in North Carolina, but a little searching on Google led me to the following links that show that the Mediterranean House Gecko has established scattered residences across many of the southern states of the United States.  

Mediterranean House Geckos can grow to about 6 inches in length.  Like other geckos, their eyes have no lids and their pupils are elliptical like a cat's.  Without eyelids, a gecko must keep its eyes clean and moist by licking them periodically with its tongue.  I read that "their eyes are 350 times more sensitive to light than humans".

Geckos are insectivores with exceptionally keen night vision. At times they can be found around outside lights where insects often gather.   

Geckos have unique feet and toes that are adapted for climbing to reach their prey. The underside of each toe is covered with a few dozen pad-like lamella which in turn are covered with thousands of tiny hair-like structures, called setae, that allow many species of geckos to climb vertical walls, and even scurry across ceilings in their search for food.  Some geckos can even climb on glass surfaces.

Once the young gecko was home, I went to buy small meal-worms and a tube of flightless fruit flies.  Right away I could tell the small meal-worms were way too large, almost half the length of the gecko's torso.  We sprinkled several fruit flies into the gecko's enclosure.  Eventually we observed the little reptile eat four or five fruit flies that ventured too close to the gecko's quick tongue.

To get a sense of size I took this picture with three coins, an American penny, a Thai 50 satang (one-half baht), and a Thai 10 baht.

This species of gecko is originally a native to southern Europe, but has successfully established itself in many places along the Mediterranean Sea, the Red Sea, and the Persian Gulf, as well as across Central America and the southern United States.

I learned from Jeff Beane at the NC Museum of Natural Sciences that there were several known populations of Mediterranean House Geckos in North Carolina.  He listed an area in downtown Raleigh, an apartment complex in Chapel Hill, somewhere in Wilmington, and a large population at East Cary Middle School that may have gotten its start 30 years ago when a few individuals escaped from a collection in a science room.

My wife also learned from a biology professor at Campbell University, that a few of these geckos have been seen around campus over the past five years.  We read that these geckos tend to associate with human dwellings, particularly large collections of dwellings, like schools and apartments, where there are plenty of places to hide during the day and plenty of insects to dine on at night.

The NC Museum of Natural Science will keep this little gecko in hopes of learning more about where the Campbell University population of Mediterranean House Geckos originated.

Friday, October 3, 2014

An Eastern Garter Snake

Last summer while working in the yard I came across a snake under some plastic plant containers that I had stashed under the deck.  I started this post soon after, but set it aside until I could develop it more fully.  I've tried to include information about a variety of characteristics of snakes in general as well as this particular snake.  I've also added some references from the web to supplement these photos to highlight the features that differentiate non-venomous from venomous snakes.  

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It had been many years since I'd seen an Eastern Garter Snake around the house.  This one was a bit aggressive at first until I got hold of her and held her for a few minutes. Then she calmed down and was fairly passive. Right away I noticed that this snake was about ready to shed her skin. Her eyes have clouded over and she cannot see very well.  As soon as she sheds her old skin, her eyes will be bright and shiny again and her vision will get back to normal.


As snakes grow they shed their old, worn, and damaged skins to make room for their increased body size, but also to rid themselves of parasites, like ticks and mites.  Young snakes may shed several times a year because they are growing more rapidly than mature snakes.  Adult snakes may shed as many as four times a year depending on how successful they have been at finding food.  The snake's tough skin protects its body against injury from things like briers and sharp rocks. Another important function of the skin is giving the snake the ability to grip the ground as it moves, and for some snake species, to climb trees.  The skin also keeps the snake from dehydrating by limiting the loss of water.  Just before a snake is ready to shed its skin it secretes a milky fluid under the old skin to help separate it from the new skin that has formed. This is what gives the snake's eye its bluish white appearance.  A snake's skin is made of a material called keratin, just like the hair and fingernails of humans.  I read on the web that while snakes shed their skin in one piece every month or so, we humans shed around one and a half million skin cells every hour. This means that about every 28 days we grow a completely new skin surface.  Wow!


In this view you can see the pattern of scales on of the top of the Garter snake's head.  Snakes are born, or hatched, with an exact number of scales.  As the snake grows, each scale gets larger.  It does not add more scales.  Below this picture is a diagram that lists the names of some of the scales that cover a snake's head.


This photo shows the pattern of scales along the snake's body.  Notice the light colored ridge along the center of the darker scales and the slightly darker ridge along the ones that make up the three rows of tan scales that form the stripe along the back of this Garter Snake.  This ridge is called a keel.  A snake with keeled scales feels rougher or more textured when held than a snake without keeled scales which feels smooth and is often glossy in appearance. Having keeled scales is an adaptation that helps a snake swim in water. Garter snakes are closely related to many species of water snakes which have strongly keeled scales.  An example of a snake with smooth scales is the Black Rat Snake.

Keeled scales

Black and White picture Keeled Scales

Smooth scales

Black and White picture Smooth Scales



This snake is well over two feet long, I'd guess closer to 30 inches in length.  According to more information that I gleaned from the internet, males are usually under two feet in length with a much slimmer body.  This lady is pretty thick, perhaps with young.  More evidence that this is a female snake is the distinctive tapering of its tail base shown in the picture below.  Notice how the tail narrows abruptly just past the cloaca or vent (a few inches from my left hand) which is typical of female snakes.  See reference material below photo.

  • "By visual appearances - male snakes have a thicker tail base where the two hemipenes lie. This can be seen, even in juvenile garter snakes, with practice.

Female Garter Snake belly scale pattern - Top three (A, B, and C)

Male Garter Snake belly pattern - Bottom two (D and E)


  • A, B & C - Female tail; ventral and lateral views.  The tail base enlargement noticeable in some females (see B) appear to male glands, but note that the tail tapers rapidly.

  • D & E - Male tail; ventral and lateral views.  Tail base is thick, and this thickness extends for some distance beyond the vent."

  • Illustration and description by kind permission of Mr Robert J. Riches, author of 'Breeding Snakes in Captivity', 1976
from: snakes


With the snake stretched out it is easy to see the definite stripe that runs the length of her back.  Eastern Garter Snake's overall color can vary from this brownish one to greenish to even reddish or bluish.  

In this side view you can see a tan stripe that is more vague running along each side. Between these stripes and the stripe along her back is a checker-board pattern of darker scales.  The overall effect gives an impression of the garters that were once worn to hold up one's socks.

The dark markings along the edges of the supra-labial scales (upper lip) helps separate this garter snake from the ribbon snakes which look similar but do not have these marks.

The Eastern Garter Snake is ovoviviparous which means that the female snake gives birth to live babies instead of laying eggs.  About half of our North Carolina snake species are live bearers while the other half are egg layers.  Garter snakes can give birth to just a few babies, but as many as 80 at one time.  Garter snakes eat a wide variety of prey including mice, worms, minnows, toads, insects, and lizards.  Garter snakes are sometimes mistakenly referred to as Garden snakes.



In this photo you can barely make out the round pupil behind the cloudy eye scale, called a spectacle or an eye cap, that will soon shed along with the rest of her skin.  All of our North Carolina non-venomous snakes have round pupils.  Our venomous snakes, except for the Eastern Coral Snake, have elliptical pupils (shaped like a cat's pupil).  See the diagram below this photo.

venomous versus nonvenomous snake head


Below is the Eastern Garter Snake's cloaca or vent.  Notice the number of scales across the belly of the snake (ventral scales).  In front of the vent (to the right) there is a series of single scales that spans the belly.  But behind the vent (to the left) there are two scales in a sort of braided arrangement (sorry, the focus isn't the greatest).  In the United States this indicates that this is a non-venomous snake.  The exception to this rule is the colorful (red, yellow, and black) Eastern Coral Snake which is limited to southern coastal areas and a very secretive reptile.  The other venomous snakes of the US have single scales across the belly almost all the way to the tip of the tail.  See the reference material below the photo.

"This is a test for identifying dead snakes or shed snake skins.  This test actually acts as an accurate marker of the snake being venomous or otherwise.  If the tail plates (plates after the anal plate) on the underside of a snake are single, the snake is most probably venomous.  Likewise, if the tail plates are in double plates, the snake is nonvenomous."

Non-venomous belly scale pattern - Top

Venomous belly scale pattern - Bottom

from :

Below is a great website showing comparisons between several non-venomous snake species and the venomous Copperhead.

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This was a satisfying encounter for me.  It brought back memories of bringing a garter snake home from junior high school in a zipper type notebook.  Of course, it escaped into my bedroom.  My engineer father cornered it in the room and caught it by the neck using a pair of Craftsman lineman's pliers!  I was actually proud of him for that, because he pretty much feared snakes.  I kept the snake for a few days before releasing it along the banks of the Kanawha River.

Being able to go over these pictures that my wife and I took of this garter snake last summer gave me the opportunity to add to what I already knew about these often misunderstood creatures. She's a beauty, isn't she?