Marine Reptiles

Sea turtles, sea snakes, marine iguanas

Characteristics

• Cold Blooded

• Ectothermic
• Body Temperature changes with the environment around them

• Reproduction

• Oviparous
• Lay eggs that hatch after an incubation period

• Incubation: the development of offspring in an egg

Sea Turtles

• Mouth

• Powerful jaws
• No teeth

• Reproduction

• Females breed every 2-4 years
• Lay eggs on land in holes in the sand
• During breeding year, females may lay up to 7 clutches of eggs
• Each clutch has an average of 120 eggs
• Incubation

• Eggs need ~60 days to hatch
• If it’s warmer they will develop more quickly, colder will develop more slowly
• Eggs start out ‘leathery’ but become more brittle before hatchlings escape

• Gender

• Temperature-dependent sex determination
• Gender of hatchling depends on the temperature of the environment egg was in.
• “Pivotal” temperature = 50% male, 50% female
• Higher or lower will produce more males or more females

• Only 7 Species

• Green
• Loggerhead
• Leatherback
• Hawksbill
• Kemp's Ridley
• Olive Ridley
• Flatback

• Species Status

• All species of sea turtles are threatened or endangered
• Endangered means that a species is under direct threat of species survival (extinction is a definite threat)
• Threatened means that the species may become endangered

• Kemp's Ridley Sea Turtle

• Smallest sea turtle

• 3 ft long; 100 lbs

• Most rare sea turtle

• Only known nesting site is in Rancho Nuevo, Mexico
• Site protected by government wildlife agencies

• Green Sea Turtle

• 2 varieties→ Atlantic and pacific
• Only vegetarian sea turtle
• called the green sea turtle because the fat in its body is slightly green as a result of its diet

• Leatherback Sea Turtle

• Largest sea turtle

• 6 ft long; 1000lbs

• Often feed on jellyfish
• Mouth and esophagus are lined with spikes made of cartilage, to prevent prey from escaping

• Threats to Survival

• Statistics

• Each year THOUSANDS of sea turtle hatchlings emerge
• Sadly, only 1 in 1,000 hatchlings survive to adulthood

• Natural threats

• Predators such as racoons, crabs, birds, and cats feed on eggs and hatchlings

• Human-caused threats

• In some cultures, sea turtles are a source of food
• Illegal Sea Turtle Shell Trade

• Bycatch

• Sea turtles are often caught in nets and fishing lines meant to catch other species

• Pollution

• Oil spills
• Debris

• Climate change

• As temperature rises and the polar ice caps melt, sea levels rise
• When sea levels rise that means less beach area for turtles to lay their eggs
• Also, as temperature rises the % of male and female hatchlings being born becomes unbalanced

Sea Snakes

• Statistics

• There are 55 species of sea snakes
• They are ONLY found in the Indian and Pacific Oceans

• Structure

• Long thin body
• Paddle-like tail for propelling through water
• Most species reach 3-4 feet in length as adults

• Reproduction

• Breed at sea
• Unlike sea turtles, most species of sea snakes are ovoviviparous

• Ovoviviparous

• Eggs hatch within body of parent
• Parent gives birth to live young

• Diet

• Sea Snakes are carnivores (eat meat only)
• Diet includes: fish, fish eggs, and eels

• Venom

• BITES from Sea snakes are VENOMOUS
• So venomous, a small drop can be FATAL to humans. (10x stronger than the cobra!)
• Fortunately, they are not known to be aggressive

Marine Reptiles

• Statistics

• ONE species
• Live EXCLUSIVELY on the Galapagos Islands

• Structure

• 2-4 feet in length
• Flattened tail for swimming
• Triangular dorsal spines

• Diet

• Marine Iguanas are herbivores and feed on ALGAE
• Like Polar Bears, marine iguanas do not spend all their time in the water
• They can spend up to an hour underwater

• Sexual dimorphism

• Males and females look different
• Males can be 70% LARGER than females
• Males display BRIGHT COLORS during mating season

• Sneezing

• Often seen with dried salt on body which has been excreted by their nasal glands