Sea Turtles Sea Snakes Marine Iguanas Saltwater Crocodiles Marine Reptiles Sea Turtles Sea Snakes Marine Iguanas Saltwater Crocodiles

The Basics Over 7,000 species Skin covered with scales Prevents water loss Eggs have a leathery shell Prevents drying out Can lay eggs on land Evolutionary advancement Ectothermic Typically found in warm waters

The Appearance of Reptiles First appeared over 300 million years ago Several different groups invaded the seas Most have become extinct Only a few still roam the seas Some are rare and endangered, others are common and abundant

Ichthyosaur

Sea Turtles 8 species – all endangered Bodies are enclosed by an armor-like shell (carapace) that is fused to the backbone Can not retract head into shell Legs are modified into flippers (swimming) Live primarily in warm water Can be herbivores or carnivores Sea grasses and seaweeds Sponges, sea squirts, barnacles, jellyfish Lack teeth, but have a strong powerful jaw

Green Turtle

Hawksbill Turtle

Leatherback Turtle

Leatherback Facts Largest sea turtle Can reach up to 7 ft, 1,200 lbs Found in a wide range of open waters, but are rarely seen except on nesting beaches Deep divers – can dive up to 2100 ft Favorite food = jellyfish

Loggerhead Turtle

Black Sea Turtle

Flatback Sea Turtle

Kemp’s Ridley Sea Turtle

Olive Ridley Sea Turtles

Sea Turtle Breeding Grounds Females must return to land to reproduce Usually a remote sandy beach Migrate up to 1300 miles to nesting grounds Can take up to 2 months May find their way by sensing the Earth’s magnetic field

Sea Turtle Reproduction Return to nesting sites every 2-4 yrs Most females return to the same beach where they were hatched Discovered by analyzing DNA of breeding populations throughout the world Copulation takes place in water near shore Female then ventures on land to lay eggs Usually occurs at night Males never leave the water

Sea Turtles – Laying Eggs Female digs hole in the sand using both pairs of flippers Lays eggs in hole Clutch size = 100 – 160 eggs Covers eggs with sand and then returns to sea One female can make several trips to the beach during one season Creates a new nest each time

Sea Turtle Hatchlings Eggs hatch after about 45-70 days of incubation depending on species Sex is determined by temperature 83-85˚ F = equal # of males and females Lower = males, higher = females Once hatched, babies dig themselves out of the sand and crawl to the water Hopefully this happens at night – less predators Enemies on land – dogs, ghost crabs, wild pigs, birds, racoons, etc Enemies in water – fish, seabirds Use cues such as slope of beach, waves, sky light to determine which way to go Approximately 0.1% of hatchlings survive to adulthood

Sea Turtles are Endangered Humans are destroying their habitat Pollution – trash, chemicals Nesting areas are becoming populated More dogs and scavenging birds People dig up nests or collect baby sea turtles Hatchlings use lights to direct them toward water, but city lights can cause them to move toward the city Get caught in fishing nets and drown Nets now have TEDs (turtle excluder device) to prevent turtle deaths A TED is an escape hatch in the net

TEDs

Sea Snakes 55 species Found in tropical Indian and Pacific Oceans 3-4 ft long Mate in the ocean Most are ovoviviparous – eggs retained within female, give birth to live young Some lay eggs Carnivorous – feed on bottom fish, fish eggs Highly venomous – can be fatal to humans Hunted for skin

Napoleon Wrasse Olive Sea Snake

Banded Sea Snake

Marine Iguana Found only in the Galapagos Islands Spend most of the time basking in large groups on rocks along coastline to warm up after swimming in cold water Dive up to 33 ft to graze on seaweed

Saltwater Crocodile Inhabit brackish water of mangrove swamps and estuaries Eastern Indian Ocean, Australia, Western Pacific Islands Worldwide population = 200,000 – 300,000 Life span = 70 yrs Feed on anything they can catch Buffalo, monkeys, wild boar, sharks, etc Can reach speeds of 15-18 mph in water (short bursts) Most aggressive of all marine animals Hunted illegally for skin

Saltwater Croc – Reproduction Males average 17 ft, 1000 lbs Mature at 16 yrs Females average 10 ft Mature at 12-14 yrs Nesting area is guarded by male and female Clutch size = 40-60 eggs Sex of hatchlings is determined by temp Cooler temps = females Female cares for young for several months Only 1% of hatchlings survive to adulthood