Herpetology

What is it?

Herpetology is the study of reptiles and amphibians

Why study herpetology?

Important implications for conservation,research and education

o Amphibians are excellent bio-indicators for environmental quality and change.

o Snake venom is proving to be very useful to the medical field (dissolving blood clots in heart attack and stroke victims).

Types of Amphibians

• Frogs• Toads• Salamanders• Caecilians

Amphibians as Bio-indicators•Because amphibians absorb water through their skin, they are often the first to suffer the effects of water or environmental pollution.•Nearly 1/3 (32%) of amphibians worldwide are threatened•Nearly 168 species are believed to have gone extinct•43% of species are in decline

Major reasons for decline:•Habitat destruction•Chytridiomycosis (a fungal disease)

Other factors: •Introduction of non-native species•Over-exploitation (pet trade)•Climate change; amphibians are very sensitive to small temperature changes, which can affect their breeding habits, reproduction and immune response•UV-B radiation (due to decreases in stratospheric ozone layer)•Chemical contaminants (pesticides, heavy metals, acidification and nitrogen based fertilizers)

Amphibians: Means “double life”

• Have gills and lungs• Are cold-blooded• Most lay soft, gel-covered eggs (exceptions include

the Fire Salamander, some African Toads and most species of Caecilians)

• Are vertebrates• Many have toxic secretions as defense

Common Salamanders of Shenandoah River State Park

Spotted Salamander

Jefferson Salamander

Dusky Salamander

Red-backed Salamander

Marbled Salamander

Valley and Ridge Salamander

Slimy Salamander

Four-toed Salamander

Newts:

• All newts are salamanders, but not all salamanders are newts.

• Newts have three distinct life stages– Aquatic larvae (tadpole)– Terrestrial adult (eft): 1 to 3 years– Aquatic adult (newt)

Red-spotted Newt(adult)

Eft(juvenile Red-Spotted Newt)

Salamander Life CycleEgg

Larvae

Juvenile

Adult

Salamander Biodiversity: • Salamanders can be aquatic, terrestrial, or a mixture

of both. Living in diverse habitats cause different species to use different types of respiration.

Types of Respiration: • External gills • Lungs • Skin/cutaneous respiration (all salamanders can do this)

Aquatic Habitat: • Larvae are born in water using

external gills • Juveniles and adults breathe through

external gills if retained, skin if not • Breathing through skin requires

constant moisture, easy if aquatic (example: Mudpuppy)

Terrestrial Habitat: • Most terrestrial salamanders lay eggs in the

water that hatch into aquatic larvae that later crawl out on land.

• A few species lay eggs on land that hatch into juveniles.

• Juveniles and Adults breathe through skin and lungs if present

• If lungs are lacking the salamander must live in a moist area to breathe through its skin

(ex.: Spotted Salamander)

Semi-Aquatic:

•Larvae are born in water and breath through external gills

• Juveniles crawl out on land and breathe using lungs. •Adults return to the water using skin to breathe, and occasionally venture on land using lungs. (example: Eastern Red Spotted Newt)

What they Eat:

Mostly insects, however, any animal they can fit in their mouth is fair game (including smaller salamanders!)

Aquatic salamanders use chemical signals to track prey

Terrestrial salamanders use vision to detect movement

What Eats Them:

Birds and snakes on land

Fish and turtles in the water

Salamander eggs have a firm, outer jelly coating that encases the eggs.

These are Spotted salamander eggs.

Common Frogs and Toads of Shenandoah River State Park

American Bullfrog

Green Frog

How to tell the difference…

Pickerel Frog

Southern Leopard Frog

Differences between the twoPickerels have a double row

of spots on their backsSouthern Leopards have irregular spots and a

white spot on the eardrum

American Toad

Fowler’s Toad

Easy way to tell the difference…

Wood Frog

Spring Peeper

Northern Cricket Frog

Gray Treefrog

Upland Chorus Frog

Life cycle of Frogs and Toads

On frog eggs, you can easily see the contour of each individual egg on the outside of the mass. This is a Pickerel Frog egg mass.

Toad eggs

Reptiles

• Reptiles are vertebrates. • Reptiles are covered in scales or have scutes. • Reptiles breathe with lungs. • Most reptiles lay hard-shelled eggs. Some

reptiles, like pit vipers, give birth to live young. • Almost all reptiles are cold-blooded. (One

exception is the leatherback sea turtle, which can regulate its body temperature to some degree.)

Snake Characteristics• Snakes have clear scales over their eyes so they do not have eyelids for blinking or closing their eyes.•Snakes do not have ears so they do not hear as we do. They feel vibrations.•Snakes use their tongues for smelling using the Jacobson’s organ•The pits on venomous snakes detect thermal infrared radiation. The pits respond to subtle thermal fluctuations in the environment and allows for an accurate measurement of the distance of a heat source.•Non-venomous snakes do not have fangs, but have rows of pointed backward-curved teeth •A snake’s jaws can come apart so that they can eat large prey. •Snakes will shed their skin several times a year as they grow.

Venomous Snakes in Virginia

Northern Copperhead

Timber Rattlesnake

Water Snakes

Northern Water Snake Queen Snake

Black Racer Eastern Ratsnake

Eastern Hognose Snake

Northern Ring-necked Snake

Rough Green Snake

Eastern Worm Snake

Milk Snake

Eastern Garter Snake

Common Ribbon Snake

Northern Red-bellied Snake

Eastern Smooth Earth Snake

Northern Brown Snake

Red Corn Snake

Turtle Characteristics

• Do not have teeth• Usually omnivores• Lay eggs and leave them. Many eggs are

eaten by predators, such as raccoons, skunks, coyotes, dogs, crows and snakes.

• Box turtle populations are in decline due to habitat loss, road mortality and collection by humans.

Aquatic Turtles

Eastern Snapping Turtle

Eastern Painted Turtle

Eastern Musk Turtle

Wood Turtle (endangered)

Red-bellied Cooter

Spotted Turtle (High conservation need)

Box Turtle (terrestrial)

Lizards of the Park

Common Five-lined Skink

Broad-headed Skink

Skinks differ from other lizards in that they have shorter limbs and do not have a defined neck.

Eastern Fence Lizard