Amphibians and Reptiles An Introduction to Herpetofauna Edited
Amphibians and Reptiles: An Introduction to Herpetofauna Edited for Virginia by Mike Clifford, Virginia Herpetological Society Eastern Hognose Snake Green Treefrog
Amphibians and Reptiles n Ectothermic n n Use outside energy sources to maintain body temperature for metabolism and regulatory functions Fence Lizard River Cooters Northern Watersnake Timber Rattlesnake Cryptic n Very difficult to detect even though they can be highly abundant Timber Rattlesnake Queen Snake
Tetrapods Snakes have evolutionarily lost their legs n Humans evolved from one of the same ancestors of extant reptiles n Non-Tetrapod Vertebrates Frogs Salamanders Caecilians Reptiles Birds Mammals Rainbow Snake Adapted from the
Amphibians and Reptiles n n Very important to the ecosystem Prey and Predator n n n Prey item for animals including raccoons, opossums, and birds Prey upon insects, mice, and rats Green Salamander Ringneck Snake Spring Salamander Bio-indicator n An animal that can indicate the health of an environment by its population structure and abundance Eastern Spadefood Toad Eastern Spiny Softshell Turtle
Amphibians n 78 Species in Virginia (51 salamanders & 27 frogs & toads) SE U. S. - greatest salamander diversity in the world! n Huge Biomass n Spotted Salamande Biomass: Total weight of all amphibians in an area n One isolated wetland produced 3 tons of amphibians n Southern Leopard Frog Three-Lined Salamander
Amphibian Characteristics n Permeable skin n Good olfaction n n 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: n Insects, other amphibians, anything small enough to fit into their mouths, even mice Spring Salamander
Frogs Tadpoles lose tails and grow legs as they metamorphose n True Frogs n n n Rana Tree Frogs Hyla n Toe pads Southern Leopard Frog Bull Frog n Spring Peeper Upland Chorus Frog Green Tree Frog Grey Tree Frog
Toads n n n 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: n American Toad Glands behind the eye that secrete toxin Fowler’s Toad
Salamanders n Plethodontids: No lungs n n Spring Salamander Ambystomatids: Lungs n n Obligate, aerobic respiration through the skin Facultative, aerobic respiration through the skin Hellbenders n n Grow to 2 feet in the USA, but up to 5 feet in Japan Hidden gills Marbled Salamander Photo by Kristen Cecala Hellbender
Amphibian Breeding Locations n Streams n n n Wetlands n n n Adults utilize upland habitat for feeding Use stream for breeding, larval period, and occasional foraging Spring Salamander Larva Adults live and feed in upland habitat Return to wetlands to breed and undergo larval periods Terrestrial n n n Adults never require water for reproduction No larval stage Utilize moisture under logs and leaf litter Redback Salamander
Caecilians Live in the tropics n Leg-less and blind n Look very similar to a worm n Caecilians
Amphibian Life Cycle Upland Chorus Frog eggs Pine Woods Tree Frog Tadpole Spring Peeper calling Cricket Frog Spring Peeper Tadpole/Metamorph
Amphibian Defense Mechanisms n American Toad Toxin in skin n Toads and Newts n Producing large numbers of offspring n Producing noisy squawks when attacked Red-Spotted Newt Green Frog Tadpole
Reptiles n 62 species in Virginia from 3 groups (30 snakes, 10 lizards including one introduced, 22 turtles) Antarctica the only continent without reptiles n Snakes have no legs, but still tetrapods n Evolutionary loss of legs n Boas still maintain a pelvic girdle n Broadhead Skink Eastern Painted Turtle Copperhead
Reptiles First vertebrates to become independent of water for reproduction n Some reptiles have reverted to aquatic lifestyles, but still reproduce without water n Sea Snakes n Snapping Turtle n Sea Turtles n Snapping Turtle
Reptiles n Ectothermic n Maintain a constant temperature range n Maintained by basking, movement, and shivering n Brummation = hibernation Yellow-bellied Slider
Crocodilians n American Alligator – not native to Virginia but is found just to the south in North Carolina American Alligators
Turtles Temperature sex determination n Vertebrae integrated into shell n No teeth: Beak similar to a bird n Omnivorous n 3 habitats n Marine n Freshwater n Terrestrial n Eastern Painted Turtle Loggerhead Sea Turtle Box Turtle Snapping Turtle
Squamata Snakes and lizards n Jacobson’s organ n Olfactory organ n Tongue flicks out of the mouth and moves chemicals in the air to the organ n n Northern Copperhead Extremely movable jaw Rough Green Snake Scarlet Kingsnake Six-line Racerunner
Lizards n Extremely variable and diverse n n Many endemic species Leg-less Lizards n n Five-lined Skink Glass Lizards or Jointed Snakes Lizards have eyelids and ear holes that snakes do not Slender Glass Fence Lizard Ground Skink
Snakes 30 species in Virginia n 3 venomous species n n n Copperhead, Cottonmouth, Timber Rattlesnake. Scarlet Kingsnake – non-venomous Most species are nonvenomous Ringneck Snake – nonvenomous Copperhead - venomous Black Rat Snake – non-venomous
Snakes n n All lack legs Lack ear openings n n n Hear vibrations through the ground Eastern Hognose Snake Shed their skin to grow Either lay eggs or give birth to live young Black Racer Redbelly Watersnake Ringneck Snake Rainbow Snake
Snake Feeding n n Entirely carnivorous Swallow prey whole n n n 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 n When detected: n Flee, musk, gape, rattle n When these do not work, snakes may strike n occurs only when a snake feels threatened and has no other option to protect itself Cottonmouth n This Brown Watersnake Northern Copperhead Eastern Hognose Snake
Conservation Many amphibians are in decline n 32% of amphibians endangered versus 12% of birds or 23% of mammals n 43% of amphibian populations are declining n Few populations are known to be increasing n Grey Tree Frog Red Salamander Eastern Kingsnake
Causes of Decline Habitat destruction n Disease n Pollution n Over-exploitation n Climate change n Invasive species n How many are human caused? n
What can you do? n n n 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
- Slides: 28