Transcript Amphibians and Reptiles: An Introduction to Herpetofauna

Amphibians and Reptiles:
An Introduction to
Herpetofauna
Compiled by the Davidson College
Herpetology Laboratory
Edited for Virginia by Mike Clifford, Virginia Herpetological Society
Eastern Hognose Snake
Green Tree Frog
Amphibians and Reptiles

Ectothermic

Regulate temperature from outside sources
Water temperature
 Basking

Yellow-bellied Slider
Northern Watersnake
Amphibians and Reptiles

Cryptic

Very abundant but their presence is largely unknown
Timber Rattlesnake
Timber Rattlesnake
Northern Copperhead
Amphibians and Reptiles

Important to the ecosystem

An important prey item for:


Raccoons, opossums, birds
An important predator of:

Mice, rats, insects
Spring Peeper
Ringneck Snake
Spring Salamander
Green Salamander
Amphibians

78 Species in Virginia
(51 salamanders & 27 frogs & toads)


SE U.S. - greatest salamander
diversity in the world!
Huge Biomass
Biomass: Total weight of all
amphibians in an area
 One isolated wetland
produced 3 tons of
amphibians
Spotted Salamander

Three-lined Salamander
Southern Leopard Frog
Amphibian Characteristics

Permeable skin



Good olfaction


Permeable: allows the transfer of
oxygen and carbon dioxide to allow
respiration
Can allow the uptake of chemicals
in the environment
Green Frog
Olfaction: Sense of smell
Prey upon:

Insects, other amphibians, anything
small enough to fit into their
mouths, even mice
Spring Salamander
Frogs



Tadpoles when they are born
Lose their tails as adults
Two main types:

Spring Peeper Metamorph
True Frogs
Bronze Frog
Upland Chrous Frog

Pickerel Frog
Tree Frogs

Toe-pads
Green Tree Frog
Grey Tree Frog
Toads



Similar to frogs
Tail-less as adults
Warty skin

Have large glands behind
each eye that secretes
toxin
American Toad
Fowler’s Toad
Salamanders

Plethodontids: Don’t have lungs
and must breathe entirely through
their skin

Ambystomatids: Have lungs, but
can also breathe through their skin

Salamanders can lay eggs in:
 Streams
 Wetlands
 Soil
Spring
Salamander
Marbled Salamander
Two-lined Salamander
Caecilians



Live in the tropics
Leg-less and blind
Look very similar to a worm
Caecilian
Caecilian
Amphibian Life Cycle
Upland Chrous Frog
Frog Eggs
Pine Woods Tree Frog Tadpole
Spring Peeper
Cricket Frog
Spring Peeper Metamorph
Amphibian Defense Mechanisms

Poison in skin

American Toad
Toads and Newts

Producing large numbers of
offspring

Producing noisy squawks
when attacked
Red-Spotted Newt
Green Frog Tadpole
Reptiles
Copperhead

62 species in Virginia from 3 groups
(30 snakes, 10 lizards including one introduced, 22
turtles)


Antarctica the only continent without
reptiles
Snakes have no legs, but still tetrapods
 Evolutionary loss of legs
 Boas still maintain a pelvic girdle
Five-lined Skink
Eastern
Painted
Turtle
Reptile Characteristics

Ectothermic behavior

Maintain a narrow temperature range


Maintained through behavioral activities such as basking
or burrowing
Brummation

Hibernation in ectotherms
River Cooters
Fence Lizard
Crocodilians

American Alligator – not native to Virginia but is
found just to the south in North Carolina
American Alligators
Turtles





Vertebrae incorporated into shell
Have a beak instead of teeth
Omnivorous
Temperature sex determination
Found in a variety of habitats:
Marine
 Freshwater
 Terrestrial

Olive Ridley Sea Turtle
Snapping Turtle
Box Turtle
Eastern
Painted
Turtle
Lizards

Extremely diverse and variable

Many islands have endemic species


Endemic: Species found in one
location but no where else
Do they all have legs?


Broadhead Skink
Glass Lizards/Leg-less
lizards/Jointed Snakes
How do you tell Glass Lizards
from Snakes?

Fence Lizard
Slender Glass Lizard
Ear openings, eyelids, tail length
Slender Glass Lizard
Snakes


30 species in Virginia
3 venomous species


Copperhead, Cottonmouth,
Timber Rattlesnake.
Scarlet Kingsnake –
non-venomous
Most species are nonvenomous
Ringneck Snake – non-venomous
Copperhead - venomous
Black Rat Snake – non-venomous
Snakes


All lack legs
Lack ear openings


Hear vibrations through the
ground
Shed their skin to grow
Black Racer
Redbelly Watersnake
Eastern
Hognose
Snake
Ringneck Snake
Timber Rattlesnake
Snake Feeding


Entirely carnivorous
Swallow prey whole





Can eat prey much larger than
themselves
Some use venom to immobilize prey
Some constrict their prey
Some actively forage for prey
Some sit and wait for prey to
approach them
Eastern Cottonmouth eating a mouse
Northern Watersnake eating a fish
Snake Defense Mechanisms


Crypsis: Staying camouflaged
When detected:
Flee, musk, gape, rattle
 When these do not work, snakes may
strike


This occurs only when a snake feels
threatened and has no other option to
protect itself
Cottonmouth
Eastern Diamondback Rattlesnake
Eastern Hognose Snake
Brown Watersnake
Conservation
Grey Tree Frog




Many amphibians are in
decline
32% of amphibians
endangered versus 12% of
birds or 23% of mammals
43% of amphibian
populations are declining
Few populations are known
to be increasing
Red
Salamander
Eastern Kingsnake
Causes of Decline







Habitat destruction
Disease
Pollution
Over-exploitation
Climate change
Invasive species
How many are human caused?
Photos by Steve Price
What can you do?





Enjoy finding and observing
amphibians and reptiles
Don’t keep wild amphibians and
reptiles as pets
Don’t kill snakes
Make sure you know a venomous
species looks like before handling
snakes, and NEVER touch or
threaten a venomous snake
Don’t release any amphibian or
reptile pet into the wild
Questions?
Corn Snake