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 Treefrog

Amphibians and Reptiles

  Ectothermic  Use outside energy sources to maintain body temperature for metabolism and regulatory functions Cryptic  Very difficult to detect even though they can be highly abundant River Cooters Timber Rattlesnake Northern Watersnake Timber Rattlesnake Fence Lizard Queen Snake

Tetrapods

  Snakes have evolutionarily lost their legs Humans evolved from one of the same ancestors of extant reptiles Rainbow Snake Non-Tetrapod Vertebrates Frogs Salamanders Caecilians Reptiles Birds Mammals Adapted from the WhoZoo

Amphibians and Reptiles

   Very important to the ecosystem Prey and Predator   Prey item for animals including raccoons, opossums, and birds Prey upon insects, mice, and rats Bio-indicator  An animal that can indicate the health of an environment by its population structure and abundance Green Salamander Spring Salamander Ringneck Snake Eastern Spadefood Toad Eastern Spiny Softshell Turtle

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

amphibians of Southern Leopard Frog Three-Lined Salamander Spotted Salamander

Amphibian Characteristics

   Permeable skin   Permeable: Allows the transfer of oxygen and carbon dioxide to allow respiration Can allow the uptake of chemicals in the environment Good olfaction  Olfaction: Sense of smell Prey upon:  Insects, other amphibians, anything small enough to fit into their mouths, even mice Green Frog Spring Salamander

Frogs

 Tadpoles lose tails and grow legs as they metamorphose  True Frogs 

Rana

 Tree Frogs 

Hyla

 Toe pads Southern Leopard Frog Bull Frog Spring Peeper Upland Chorus Frog Green Tree Frog Grey Tree Frog

Toads

     Similar to frogs Tadpoles lose tail and grow legs as they metamorphose into adults Less dependent upon water than frogs Have warty skin Paratoid Glands:  Glands behind the eye that secrete toxin American Toad Fowler ’ s Toad

Salamanders

   Plethodontids: No lungs  Obligate, aerobic respiration through the skin Ambystomatids: Lungs  Facultative, aerobic respiration through the skin Hellbenders   Grow to 2 feet in the USA, but up to 5 feet in Japan Hidden gills Spring Salamander Marbled Salamander Photo by Kristen Cecala Hellbender

Amphibian Breeding Locations

   Streams  Adults utilize upland habitat for feeding  Use stream for breeding, larval period, and occasional foraging Wetlands  Adults live and feed in upland habitat  Return to wetlands to breed and undergo larval periods Terrestrial  Adults never require water for reproduction   No larval stage Utilize moisture under logs and leaf litter Spring Salamander Larva Redback Salamander

Caecilians

 Live in the tropics  Leg-less and blind  Look very similar to a worm Caecilians

Spring Peeper calling

Amphibian Life Cycle

Upland Chorus Frog Frog eggs Pine Woods Tree Frog Tadpole Cricket Frog Spring Peeper Tadpole/Metamorph

Amphibian Defense Mechanisms

American Toad  Toxin in skin  Toads and Newts  Producing large numbers of offspring Red-Spotted Newt  Producing noisy squawks when attacked Green Frog Tadpole

Reptiles

  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 Broadhead Skink Eastern Painted Turtle Copperhead

Reptiles

 First vertebrates to become independent of water for reproduction  Some reptiles have reverted to aquatic lifestyles, but still reproduce without water  Sea Snakes  Snapping Turtle  Sea Turtles Snapping Turtle

Reptiles

 Ectothermic  Maintain a constant temperature range  Maintained by basking, movement, and shivering  Brummation = hibernation Yellow-bellied Slider

Crocodilians

 American Alligator – not native to Virginia but is found just to the south in North Carolina American Alligators

Turtles

 Temperature sex determination  Vertebrae integrated into shell  No teeth: Beak similar to a bird  Omnivorous  3 habitats  Marine  Freshwater  Terrestrial Box Turtle Eastern Painted Turtle Loggerhead Sea Turtle Snapping Turtle

Squamata

 Snakes and lizards  Jacobson ’ s organ  Olfactory organ  Tongue flicks out of the mouth and moves chemicals in the air to the organ  Extremely movable jaw Northern Copperhead Six-line Racerunner Rough Green Snake Scarlet Kingsnake

Lizards

 Extremely variable and diverse  Many endemic species  Leg-less Lizards  Glass Lizards or Jointed Snakes  Lizards have eyelids and ear holes that snakes do not Five-lined Skink Fence Lizard Slender Glass Lizard Ground Skink

Snakes

   30 species in Virginia 3 venomous species  Copperhead, Cottonmouth, Timber Rattlesnake. Most species are non venomous Scarlet Kingsnake – non-venomous 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 Either lay eggs or give birth to live young Black Racer Redbelly Watersnake Rainbow Snake Eastern Hognose Snake Ringneck Snake

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 Northern Copperhead Eastern Hognose Snake Brown Watersnake

Conservation

    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 Bog Turtle Eastern Kingsnake Grey Tree Frog Red Salamander

Causes of Decline

 Habitat destruction  Disease  Pollution  Over-exploitation  Climate change  Invasive species  How many are human caused?

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

Corn Snake

Questions?