Tuesday, February 26, 2013

Expect the Inexpectatus

     Today's field trip took place in historical Charleston, SC at Caw Caw County Park. The adventure began just as the sun was setting overhead. The mellow rays displayed a sun-kissed landscape painted with vibrant greens and lush browns. Moments after entering the forest the scene transitioned to a serene aquatic habitat of bountiful blue water scattered with yellow accents of our state flower Gelsemium sempervirens. This tranquil swamp set the stage for my class's first ever search-for-herps.

      For an amateur herpetologist netting an aquatic squamate is like shooting a target while blindfolded. Accomplishing either proves a tedious task, requiring more patience than luck. I focused my search primarily under shrubs, foliage and fallen trees. As I stabbed my net into the water I slowly slid my feet through the murky shallows and rapidly pulled up to loot my catch. Several repeated attempts produced a smorgasbord of leaves, mainly Liquidambar styraciflua and plants of the Lemnaceae family, but no squamates. My fruitless search continued for awhile until I found a large cypress that had succumbed to gravity some years before. This seemed like a promising location so I stepped onto the rotting wood and shuffled across while balancing cautiously. With the grace of a drunk tightrope walker I hesitantly shimmied across the slippery, waterlogged bark while firmly grasping my net and-SPLASH! The log crumbled beneath me and I fell what seemed like faster than anything gravity was capable of while grasping desperately to my net. There I was, hip-deep in swamp water and staring unexpectedly at the tail of a Southeastern five-lined skink sticking out of the cypress. Overwhelmed with excitement I ignored the water rushing into my waders and quickly pulled the skink out of the log by its fragile tail. I placed the specimen into my net and delivered it to my eager classmates for identification. At this moment I pondered the irony of the situation. I caught a terrestrial skink by hand while submerged in water while holding a net. Go ahead, laugh at the stupidity that sequenced these events. I did, too. My skink was a juvenile which potentially explains where it was found. I surmise that its mother laid her eggs on the island that was the fallen cypress because of the cryptic locale and plentiful food source contained within it. Upon placement into the net the skink put great effort towards escape. I've never witnessed such a climber; its climbing ability paralleled that of Spiderman. The skill I witnessed was representative of its arboreal nature-useful for foraging and basking in the sun, but unfortunately not good enough to escape the rim of a well-woven net. Keep this in mind if you're ever in the presence of any majestic creature that possess super-squamate climbing skills.

      Although heavily populated in the southeast, finding Plestiodon inexpectatus can be a daunting task as they often find refuge in stumps, logs or decomposing piles of wood. These five-lined skinks are active during the day spending most of their time foraging the forest floor. Mating season occurs in the Spring and females typically lay their eggs under rocks or in rotting wood to avoid predation. After 1-2 months the eggs hatch juveniles that resemble adult females in coloration and pattern until directly developing into adults. At adulthood female coloration will fade and their tail will turn grayish while males turn darkish brown and display orange jaws during mating season.

As I finish writing I feel anticipating for our next field trip. This was a memorable experience that provided the opportunity to appreciate the intelligence and warm-hearted-nature of my classmates while applying my brick-and-mortar education to real world herps. 

Thursday, February 21, 2013

Times they are a-changin’: Effects of climate change on endangered amphibians



Global climate change is real. We are living in an age of overwhelming evidence. For example, last December I was wearing shorts and a t-shirt in upstate Ohio – not normal. But while we have been aware of this threat for some time, the effects of climate change on many groups of organisms are poorly understood. One such group is amphibians; those sometimes slimy, hopping, misunderstood (you can’t get warts from a toad) creatures. Amphibians are one of the most sensitive groups of organisms on the planet to environmental change. Approximately 40% of amphibians are threatened or endangered and climate change has been implicated as a major driver of amphibian declines. That is why a group lead by Benjamin Scheele of Australia National University set out to determine how climate change has affected the endangered northern corroboree frog (Pseudacris pengilleyi).
The corroboree is a small frog with a limited distribution, occurring largely within nationally protected areas. So, factors implicated in amphibian declines like habitat loss and environmental contamination should not affect these individuals. However, a decline of 42% was observed over 13 years in southern Australia. Initially, research indicated that the extinctions were the result of Batrachochytrium dendrobatidis (Bd), an emerging infectious amphibian disease that has been linked to declines worldwide. While Bd was an initial driver of the extinctions, Bd now persists in populations without causing further declines. Perplexed, researchers turned to climate change as the primary culprit.
One misconception about climate change is that it just causes warmer temperatures. While largely true, climate change also affects seasonality and subsequent precipitation. Because amphibians like the corroboree breed and lay their eggs in waterbodies, environmental desiccation (dryness due to reduced precipitation) reduces the chance of offspring survival into the next generation. With this in mind, the team set out to analyze 10 years of previous data and conducted their own surveys. They divided their sampling areas between three primary sites: frogs present, extinct (historically present), and historically absent. They also divided each site into pools, with or without frogs, and each pool into nests (present, possibly present, or absent). What they found was striking.
Over the course of 10 years, annual and autumn precipitation declined by 20% and 38%, respectively, with sharp increases in mean annual temperatures. These changes altered the amount of water that entered waterbodies with runoff declining 40%, indicating a period of unprecedented drought. Not surprisingly, the team found positive correlations between sites with frogs and the presence of water. Conversely, in areas of increased dryness, tree invasions occurred, indicating the longevity of the drought conditions. Taken together, the results showed that the climate extreme primarily affected the corroboree through habitat desiccation, lowering future survival.
So what does this mean for us? Well, it’s a question I really hate to answer because it shouldn't matter – we caused the problems and they are our problems to remedy. However, there are many direct benefits that we gain from amphibians. Amphibians, especially frogs, are a crucial part of the food web; they help fight the spread of, and provide remedies for, human diseases. Many insects spread diseases such as dengue fever, West Nile, and malaria, and these insects are also a primary part of frog diets. So, less frogs leads to more disease-carrying insects and higher prevalence of disease. Also, frogs produce skin secretions that have been used in medicines that treat conditions such as high blood pressure and peptic ulcers, and diseases such as diabetes and HIV. Frogs are also important bioindicators. Their skin is extremely permeable and susceptible to aquatic pollutants. Thus, the health of frogs is thought to be an accurate predictor of environmental health – the environment in which we live.
We have been aware that climate change is a real problem. In this study, Scheele and his team have provided evidence that the recent declines in the corroboree can be linked to warming temperatures, reduced rainfall, and increased habitat desiccation that ultimately reduced survival. The researchers propose that in order to mitigate the negative effects of climate change, efforts must be made to provide suitable habitats that will be able to persevere in the changing world. However, no matter the solution, we are the driving force behind many of the factors (including climate change) that are responsible for the current amphibian declines and must take steps to ameliorate our effects on natural systems before species like the corroboree are gone for good. 

Scheele, B. C., D. A. Driscoll, J. Fischer, and D. A. Hunter. 2012. Decline of an endangered amphibian during an extreme climatic event. Ecosphere 3(11):101. http://dx.doi.org/10.1890/ES12-00108.1 



Wednesday, February 20, 2013

The Veiled Chameleon


             I have a couple of friends that have a lot of reptile pets. A couple of them have had chameleons and I have always thought they were really cool. I have a friend now that has a veiled chameleon.
            The veiled chameleon’s scientific name is Chamaeleo calyptratus. They are from Yemen and southern Saudi Arabia and live in a variety of habitats. They are arboreal and are very adapted for life in the trees. Their narrow bodies allow them to blend in with the leaves even when they move they rock their bodies back and forth as a leaf would. They have a prehensile tail that works like a 5th limb and their hands allow for grasping limbs of trees. A very known characteristic of chameleons are their independently moving eyes, allowing them to see what is in front of them as well as what is behind them at the same time. Their life span is about five years for females and 8 years for males.
            Veiled chameleons have a reputation for being somewhat aggressive. They are mostly omnivorous. They mostly eat insects but will sometimes eat leaves, flowers and fruits. They catch their prey by using their long tongue, and contrary to popular belief it is not sticky. Instead, the end of their tongue has a grasping structure on the end of it that will grab the prey like a hand would.  
            Veiled chameleons reach sexual maturity at about 5 to 6 months of age. They can have up to three clutches of eggs a year with each clutch containing about 20-100 eggs. They are mostly solitary animals where they males are very territorial and males and females usually only come into contact with each other during mating.
            Both males and females are primarily green but the males tend to be marked with yellow, brown, and blue stripes and females are usually marked with some white. Chameleons are famous for changing color. Although, most people think that they change colors to bend in with their environment, they actually change colors according to emotional states, health, temperature and mating. In fact, about 18 hours after mating, the female veiled chameleon will change colors.
            Although they are not listed on the endangered list, they are suffering from habitat loss. Veiled chameleons are also one of the most abundant commercially due to the fact that they are very tolerant of habitat extremes and compared to a lot of chameleons they tend to do very well in captivity. Also, a disturbing yet interesting fact, a lot of wild chameleons are sold for rituals. In some cultures it is good luck to throw a live chameleon into a fire.


KENNETH L. KRYSKO(1), KEVIN M. ENGE(2), AND F. WAYNE KING(1),THE VEILED CHAMELEON, CHAMAELEO CALYPTRATUS:A NEW EXOTIC LIZARD SPECIES IN FLORIDA, Florida Museum of Natural History, Division of Herpetology

The Alligator Snapping Turtle

Macrochelys temminckii, The Alligator Snapping Turtle, is a very beautiful and fearsome member of the family Chelydridae. It is characterized by its large size, sharp beak with a worm-like structure in the mouth, a very thick carapace with raised osteoderms, and rough skin with sharp claws on its feet.  It appears green or brown overall which helps camouflage it so it cannot be seen by its prey.  

The Alligator Snapping Turtle occurs from Louisiana north in Mississippi valley to Illinois and from Oklahoma and Texas east to northern Florida.  They typically live anywhere from 20 to 75 years in the wild, and can weigh up to 250 lbs.  Their diet consists almost exclusively of meaty foods either dead or alive, and can consists mainly of fish, crustaceans, small to medium sized mammals, and some amphibians and reptiles including other turtles.  

Macrochelys temminckii reaches maturity around 10 to 12 years of age, and mating occurs in the spring.  Females go on land and build a nest where it lays a clutch of anywhere from 10 to 50 eggs.  Like some other reptiles and crocodilians, Alligator Snapping Turtles' sex is determined by the temperature of the environment while the eggs are incubating.  Higher temperatures lead to a higher ratio of females being born, while lower temperatures lead to a higher ratio of males.

The Alligator Snapping Turtle spends most of the day laying at the bottom of a body of water with its mouth open waiting to catch unsuspecting creatures, and usually only forage for food at night.  They use a curious appendage in their mouth that mimics a worm to attract live prey to their mouth which promptly shuts on the unlucky suspect.  There are no real natural predators to the Alligator Snapping Turtle except for humans who usually kill them for their meat. 

The Alligator Snapping Turtle can be distinguished from the Common Snapping Turtle (Chelydra serpentina) by the 3 rows of large osteoderms on its shell, as well as its extra large head relative to its body.  


                             Common Snapping Turtle (Chelydra serpentina)           

The Common Snapping Turtle also has a much larger natural range extending from southern Texas and Florida north to southern Canada, and all along the eastern U.S. west to eastern Colorado and New Mexico.

The Alligator Snapping Turtle has appeal in the pet trade due to its interesting feeding behavior and relatively easy care requirements, the biggest restriction being their large adult size.  They are also popular mainstays in public zoos for the same reasons.  The Alligator Snapping Turtle has also been featured in popular media, namely the movie Teenage Mutant Ninja Turtles II: The Secret of the Ooze, where a character named Tokka is an alligator snapping turtle that is exposed to the same ooze that gave the Teenage Mutant Ninja Turtles their powers and abilities. 

                             Pictured: Tokka from TMNT II: The Secret of the Ooze

Sources:
http://en.wikipedia.org/wiki/Alligator_snapping_turtle#cite_note-6

Conant, Roger, and Joseph T. Collins. Field Guide To Reptiles And Amphibians. 4th ed. Houghton Mifflin Harcourt, 1998. Print.

Python regius: The ball python


A few years ago one of my little cousins got a ball python as a pet, and as a result I was introduced to this species of snake. I didn't know much about this snake nor did I ever really think about learning about it either, that is until I started taking herpetology. 
     The scientific name of this snake is Python regius and the common names that are associated with this snake are the ball python or the royal python. The common name, the royal python, is believed to come from stories of Cleopatra wearing this species of snake around her wrist as a bracelet. (http://www.worldofballpythons.com/python-regius/). This snake can be found in the wild primarily in western and central Africa. The habitats that these snakes inhabit can range from open forests to savannas and this species is "crepuscular, " meaning that they are most active at dusk and dawn. (http://animal.discovery.com/guides/reptiles/snakes/ballpython.html).  They are constrictors and as such are not venomous. In the wild they primarily feed on small mammals. These snakes have a life span of about ten years in the wild and can range anywhere from twenty to thirty years in captivity. Typically they grow to be three to five feet in length with the females being generally "larger and heavier bodied than [the] males." (http://www.a1pythons.com/ball.html). When threatened or stressed these snakes coil or ball themselves up into a tight ball with its head and neck tucked into its body. Due to this behavior this snake got the common name the ball python. These snakes are also a fairly docile species and as a result do not bite that often. When they reproduce they usually leave on average a clutch size of about six eggs, which would incubate for about 57 days at about 88-90F degrees. (http://www.a1pythons.com/ball.html). 
     Personally if I were to own any type of snake, this would be the snake that I would own. I say this simply because they are fairly simple to take care of, they don't get quite as big as some of the other constrictors, they don't bite that often, and to top it all off they are pretty cool to look at as well. 

Sources:
     http://animal.discovery.com/guides/reptiles/snakes/ballpython.html
     http://www.snakes-uncovered.com/Ball_python.html
     http://www.a1pythons.com/ball.html
     http://www.worldofballpythons.com/python-regius/
     http://www.sandfiredragonranch.com/images/Ball_python02.jpg 



                                  Photo of my cousins ball python.




 [This photo came from: (http://www.sandfiredragonranch.com/images/Ball_python02.jpg)]