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Reptiles : Alligators & Crocodiles Snakes & Iguanas Sea Turtles. Pgs 5-77 thru 5-80. Reptile Characteristics. Ecothermic vertebrates Breathe with lungs Skin made of scales (no hair; no feathers) 3 chambered heart Internal fertilization; lay eggs with soft shells
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Reptiles: Alligators & Crocodiles Snakes & Iguanas Sea Turtles Pgs 5-77 thru 5-80
Reptile Characteristics • Ecothermic vertebrates • Breathe with lungs • Skin made of scales (no hair; no feathers) • 3 chambered heart • Internal fertilization; lay eggs with soft shells • 1st to see Amniotic Egg • A thin, membranous, fluid-filled sac surrounding an embryo which keeps the embryo from drying out. • Reptiles, birds, & Mammals • Offspring look like its parents • Examples: alligators, crocodiles, turtles, lizards, & snakes
Order Crocodilia • Salt Water Crocodile • Grow to 20 feet • Can live in the ocean, but primarily estuaries • American Alligator • largest reptile in N. America. • grow to be 6’-19’. • found in Coastal N. Carolina to Florida, along the southern coast of Texas, and North to SE Oklahoma and Arkansas. Crocodile Alligator
How can you tell the difference? Similar… Difference… • Alligators-rounded snout • Crocodile’s mouth is more pointed (triangular shape) & its teeth are visible. • both very large reptiles. • Live near fresh water • When there is a drought an alligator is known to dig a deep hole or “den”, • provides water for the wildlife around them.
Order Squamata • Sea Snakes • Have flattened tail to swim • breathe air • Can remain underwater for hours • Venomous • Hunt small fish • Not a major threat to humans b/c fangs are small & back of mouth; less territorial than terrestrial • Can be fatal unless given antivenin
Order Squamata • Marine Iguana • Live in the Galapagos island • Herbivore • Live & forage under water • Salt glands on nose to eliminate excess salt
Marine Iguana Podcast • http://education.eol.org/podcast/marine-iguana • (~5 min) • 1. What eats a marine iguana? • 2. How do they know when the predator is coming? • 3. What were the observations made by scientists between iguanas and mockingbirds?
Order Chelonia • 7 species of marine turtles • 5 common to Florida • Leatherback • Green • Loggerhead • Hawksbill • Kemps Ridley • Olive Ridley • Flatback. • Note * Olive ridley & Flatback turtles not seen in Florida. • All live in warm waters
Sea Turtle Nesting • Females return to same the same beach biannually for nesting • only during the summer months • Dig a hole in the sand using front flippers • ~100 ping-pong sized eggs laid/ nest • Nest temperature determines sex of hatchlings • Warmer- females • Cooler- males • Incubation is approximately 2 months • Hatching & emergence can take a couple of days (2 to 3 days) • 1 in 1,000 eggs will survive to adults
Marine Turtle Adaptations • Legs • Modified flippers • Move in water & on land • Beaks- no teeth • Can hold breath for up to 3 days by slowing heart rate • Papillae in esophagus • White teeth like structures • Help keep the food down in the stomach.
Adaptations continued… • Shell • Carapace (top ) • made up of bony plates • covered by a layer of scales called scutes • Plastron (bottom) • Provides Protection • Excrete excess salt through tear ducts (Lacrimal Gland)
Named for it’s abnormally large head. Avg. adult weight is 275 lbs Heart shaped carapace reddish brown on top & creamy yellow underneath 5 lateral scutes Has two claws on each front flipper Diet: clams, crabs and other armored animals. A slower swimmer, it can fall prey to sharks but can travel great distances quickly 1. Loggerhead Turtles
Where in FL Can You Find a Loggerhead Sea turtle? • Only species of sea turtle not to be listed as endangered • List as threatened • Most common species found in FL • Approximately 15,000 females nesting here annually Other Florida Counties South Florida Counties
2. Green Turtle • Named for their green body fat • Were valued for their meat, hide, eggs and “calipee” • used for green turtle soup. • Diet: vegetarian species • Habitat: shallow flats & sea grass meadows • Approx 100-1000 Green turtles nest on FL beaches annually
Green Turtle • 4 lateral scutes • 1 claw on each front flipper • Avg adult weight is 350 lbs • Oval shaped carapace • olive-brown with darker streaks • plastron is yellow
3. Leatherback marine giants • Avg 6 feet in length • weigh btwn 500- 1500 lbs • Carapace is made up of leathery skin (not bony scutes) • 5 ridges • Black with white, pink and blue highlights in color • No claw on front flippers
Nomads of the Sea • Diet: soft-bodied animals (jellyfish) • Use teeth-like Papillae to hold onto food • Rare to FL • Only 30-60 females nest in Fl a year • Able to dive 3,000 feet below • Can travel 3000 miles away from their nesting beaches • They regulate their own body temperature to live in varying global conditions
Named after their raptor-like jaw Diet: sponges. Adults weigh bwtn 100-200lbs & are 30 inches long Habitat: lagoons, reefs, bays, & estuaries Atlantic, Pacific, & Indian Oceans Common in Fl. Keys 4. Hawksbill Turtles
Hawksbill • Carapace is shaded with black & brown markings on an amber background • Overlapping scutes • 4 lateral scutes • Curved beak with distinct overbite • 2 claws on front flippers
Hawksbill Hazard’s • The shell is used to make jewelry, hair decorations and other ornaments
Named for Richard M. Kemp a fisherman who submitted the type specimen from Florida The rarest and most endangered sea turtle in the world Avg size is 85-100 lbs 2 to 2.5 feet in carapace length Diet: crabs & other crustaceans Captive breeding attempts for this species not a viable option 5. Kemp’s Ridley
Arribadas • Synchronized nesting habits of Ridley turtles • Turtles mate offshore • Females nest 3x per season on the beaches • Mating/nesting continues for a week or so • Triggered by the moon? Pheromones?
Human impacts to Sea turtles… • All are endangered or threatened • 1. Habitat degradation • Sea walls & development of houses/hotels • Affects nests • 2. Pollution – oil spills; plastic bags
Human impact continued… • 3. Bycatch & entanglement
4. Hunting • Eggs harvested/poached • Shells used in jewerly & decor • 5. Light Pollution • Turtle look for the moon light over water • Hatch and move toward higher ground due to lights on houses
What can we do? • Turtle Exclusion Devices (TEDs) • Trapdoors allow larger animals to push themselves out of the net • Only marginally effects the success of the net • ~ 11,000 turtles estimated to have been killed annually in nets prior to TEDs • Kemp’s Ridleys were hardest hit • Nesting activities have increased since TEDs use