Transcript Class Reptilia (marine reptiles)

Marine Reptiles
• Reptiles are cold-blooded, air-breathing
animals with tough, scaly skin
• Marine reptiles include:
– Sea turtles (7 species)
– Sea snakes (55 species)
– Marine crocodiles (1)
– Marine lizards (iguanas; 1)
Marine Reptiles
• Like most fish, marine reptiles are ectothermic
and poikilothermic; “cold-blooded”
• Marine reptiles breath air; they have internal
lungs, not gills
• Marine reptiles are equipped with special salt
glands to concentrate and excrete salts
• Leathery shells prevent eggs
from drying out
Marine Reptiles: Sea Turtles
• Sea turtles belong to an ancient group of
reptiles
• Their body is enclosed by an armor-like shell,
or carapace that is fused to their backbone
• All are streamlined and adapted for life in the
water
– Forelimbs are modified into flippers
– Hindlimbs act as rudders
– Cannot retract head or limbs
Marine Reptiles: Sea Turtles
Our Local Sea Turtles
scienceblogs.com
Leatherback
Hawksbill
http://www.costaricaturtles.com/costa_new_seaturtles.html
http://fwie.fw.vt.edu
Green
www.underwater.com.au
Loggerhead
www.dnr.state.md.us/
fisheriesoxford/
research/fwh/
seaturtles.html
Kemp’s Ridley
Marine Reptiles: Sea Turtles
• Sea turtles spend their entire lives at sea; only
females come ashore to lay eggs
– Homing (return to same beach where they were
born to lay eggs)
http://www.youtube.com/watch?v=UKkScAel52w
http://www.conservation.org/great_turtle_race/Pages/main.aspx
Temperature-dependent Sex
Determination
• When female sea turtles come ashore to lay
their eggs, the depth of the burrow she digs
affects the temperature of the eggs that are
laid
• Temperature (not genetics)
determines the sex of the
offspring
– Warmer nests  females
© Aqua Image/age fotostock
Got Arribada?
• Female sea turtles aggregate on the beach in
mass nestings called arribadas
http://www.youtube.com/watch?v=W4u3GL9SyyM
Save the Sea Turtles!
• Most of the world’s sea turtles are threatened or
endangered with extinction
• Dangers include:
– Shrimp trawling; Long-line fishing
– Beach destruction, hardening of shorelines, vehicles
and dogs on beaches
– Bright beach lights
– Marine debris; Ghost
netting
– Global warming
Credit: © James Watt/Visuals Unlimited
…and closer to home
• Every fall and winter, the local sea turtles off Long
Island need to return south to the warmer waters
of the Caribbean and the Gulf of Mexico
• Sea turtles that remain
can
become “cold
stunned”
– <50°F
– Call the Riverhead
Foundation: 369-9840
Marine Reptiles: Sea Snakes
• Approximately 55 species of sea snakes are
found in the tropical Indian and Pacific oceans
• The tail end of sea snakes is flattened into a
paddle-shape for swimming
• A few species return to
land to lay eggs, but
most give birth to live
young underwater
– ovovivipous
Marine Reptiles: Sea Snakes
• Sea snakes are closely related to cobras; the
most venomous of all snakes
• Sea snake bites can be fatal to humans;
extremely venomous
– Why?
Marine Reptiles: the Marine Iguana
• The marine iguana is found on the Galapagos
Islands, off the coast of South America
• Marine iguanas survive in the cold, upwelled
waters off the Galapagos by frequently
basking on the rocks to raise their body
temperature
• Feed on algae
• Efficient swimmers
Marine Reptiles: Saltwater Crocodile
• The saltwater crocodile inhabits mangrove
swamps and estuaries in the eastern Indian
Ocean, Australia, and some of the western
Pacific islands
• Very aggressive; fatal
attacks on humans
• Commonly 20ft long
• Inhabits coast,
rivers and open sea
© Susan Flashman/ShutterStock, Inc.