Powers Marine Reptiles

Marine Reptiles

Marine Crocs, Snakes, Lizards, and Turtles

Marine Reptiles

• 4 groups include:

– Saltwater crocodile
– Sea snakes
– Marine lizard
– Sea turtles

Marine reptiles

• Adaptations of Marine Reptiles

– Lungs
– Amniotic egg – large yolk to nourish developing embryo
– Leathery egg case – prevent drying out
– Internal fertilization
– Most return to land to lay eggs (turtles and crocs)
– 3 chambered heart (croc has 4 chambered)
– Salt glands to get rid of excess salt
– Ectotherms (cold blooded) so most live in warm waters

Saltwater Crocodiles

• American Saltwater Crocodile
• Crocodylus acutus
• In US – only located in
Florida
• Nonaggressive and shy
• Up to 15 feet long
• Endangered (500 – 1200 left)
• 4 chambered heart
• Lay eggs in nest and

Saltwater Crocodiles

• Australian Saltwater crocodile
• Crocodylus porosus
• Inhabits mangroves and estuaries
• Indian ocean and some western pacific islands
• Most live on the coast but are known to venture out

into the sea

• Up to 30 feet long
• Very aggressive
• Status – of least concern
aussie salt croc.flv

Sea Snakes

• About 50 species (Order Squamata)
• All are venomous (although not aggressive)
• Related to cobras
• Flattened, rudder-like tails
• Flaps on nostrils to keep closed

underwater

• Salt gland in mouth
• One long lung lined with blood

vessels to increase O2 absorption
with simple sac at end to store air

• Can hold breath for 2 hours
• Most venomous of ALL snakes
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• Bradycardia - decrease in

heartbeat in response
to diving
(43/min to 7-9/min)

• Reproduction - internal fert

– Sperm is implanted into oviducts and can be

stored for weeks or years until eggs are ripe

– Most are ovoviviparous (bear live young)
– Some are oviparous (lay eggs)

Sea Snakes

• Olive Sea Snake (Aipysurus laevis)
• Up to 6 feet long
• Fish eater – corners fish in crevices
• Indo-pacific including Australia usually near

coral reefs

Sea Snakes

• Yellow Bellied sea snake
• Pelamis platurus
• Pacific waters – Cali to Ecuador
• Most widely distributed snake
• Float at surface like driftwood

to attract small fish – ambush
predator

Sea Snakes

Marine Lizard

• Only one species – the Marine Iguana
• Amblyrhynchus subcristatus
• Live in large colonies on the Galapagos islands

• Specific adaptations include

– Flattened tail for swimming
– Webbing on all 4 feet
– Salt glands above eyes
– “sneeze” to expel salt
– Powerful claws to

anchor in heavy seas

– Regulate buoyancy

by expelling air

iguana.flv

Marine Lizard

Sea Turtles

• Most widely distributed marine reptile
• Sea turtles have been hunted for meat, eggs,

shells, leather,
and decorative
objects

• They are now

becoming
victims of
pollution and
accidental
bycatch

• Characteristics

– Non retractable heads and limbs
– Powerful front flippers to propel and hind fins

used for stabilizing and steering

– Shells streamlined and flattened
– Fatty deposits and light bones increase buoyancy

Sea Turtles

• Feeding

– Most turtles feed in shallow coastal waters
– Vegetarian turtles

• Green turtle feeds on meadows of turtle grass

throughout the tropics

• Black sea turtle feed on algae and sea grasses

– Carnivorous turtles

• Loggerheads, Hawksbill, Olive Ridley, Leatherback,

Kemp’s Ridley, Flatbacks

• – feed on crabs, shellfish, urchins, seaweed, sea

cucumbers, sponges, fish

Sea Turtles

• Reproduction

– Born on land but spend

their lives at sea

– Mature sea turtles return

to the beaches on which
they were born to lay eggs

– Mating occurs in shallow

waters

Sea Turtles

– Female swims to shore at night and drags herself

along the beach to find the nesting site

– She digs a hole and deposits about 100 eggs
– False Crawl – female comes ashore then leaves

without laying eggs

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Sea Turtles

– Embryos

develop for
about 2 months

– Eggs at about

30C+ become
female, eggs at
28C or lower
become male

Sea Turtles

• Hatchlings breaks through shells and wiggle down to

the sea

Sea Turtles

sea turtle babies emerging.flv

Sea Turtles

• 8 species – all endangered and protected

Sea Turtles

Atlantic Leatherback

(Dermochelys coriacea)

• Largest turtle – up to 6 feet long, 1100 pounds
• Rare visitor to Texas Gulf coast
• No true shell – leathery, scaleless skin, 7 ridges
• Feed mostly on jellyfish

Atlantic Leatherback

(Dermochelys coriacea)

• Primary breeding grounds – Pacific coasts of

Mexico and Costa Rica

• Reach sexual maturity at 8-15 years
• Lay 50-180 eggs, incubation takes 50-55 days
• Status – endangered

Atlantic Leatherback

(Dermochelys coriacea)

leatherbacks.flv

Flatback Turtle

(Natator depressus)

• Flat carapace – olive gray color
• Up to 3 feet long, almost 200 pounds
• Exclusively breeds and nests in Australia
• Lays about 50 eggs (the fewest of all turtles)
• Incubation 60 days
• Sexual Maturity at

7 – 50 years

• Feeds mostly on

jellyfish, inverts,
sea cucumbers

• Status - vulnerable

Flatback Turtle

(Natator depressus)

Hawksbill Turtle

(Eretmochelys imbricata)

• Hawk-like bill – designed for foraging in coral
• Scutes on carapace overlap each other
• Up to 132 pounds, just over 3 feet long
• Feeds on sponges, jellyfish, sea stars, fish,

urchins, crustaceans

• Eat poisonous sponges

and store toxin in flesh

so this turtle is

poisonous if eaten

Hawksbill Turtle

(Eretmochelys imbricata)

• Lay about 160 eggs, incubate for about 55 days
• Reproductive maturity is 20-25 years
• Status –

endangered

hawksbill.flv

Hawksbill Turtle

(Eretmochelys imbricata)

Olive Ridley

(Lepidochelys olivacea)

• Olive gray above and creamy white below
• Up to 100 pounds, about 2.5 feet long
• Feed mostly on lobsters, fish, crustaceans, algae,

fish eggs, and jellyfish

Olive Ridley

(Lepidochelys olivacea)

• Arribadas – nesting behavior in which breeding

turtles congregate and emerge from the sea – en
masse!

Olive Ridley

(Lepidochelys olivacea)

• Lay ~100 eggs each, incubate for 45-65 days
• Sexual maturity about 15 years (females at least 2 feet long)
• Hatchlings born black – so easy prey against sand
• Many predators for hatchlings – 1 survives for every 3000

eggs laid!! ☹

olive ridley.flv

Olive Ridley

(Lepidochelys olivacea)

Kemps Ridley

(Lepidochelys kempii)

Kemps Ridley

(Lepidochelys kempii)

• Smallest sea turtle – up to 2 ft

long, 90 pounds

• Nest only in the Gulf of Mexico

– Rancho Nuevo, Mexico
(primary site)

• Feeds mostly on crabs, shrimp,

and fish

• Reach sexual maturity at 11-35 years
• Arribada nesting behavior too – like Olive Ridley
• Nesting season is April to July
• Lay ~100 eggs,
• incubate for 48-62 days

Kemps Ridley

(Lepidochelys kempii)

• Status – most endangered of all turtles
• Only 2500 females left today – but just 50 years ago

40,000 females were filmed nesting in just one day on
a single beach – so what happened???

• kemps ridley arribada.flv

Kemps Ridley

(Lepidochelys kempii)

Loggerhead

(Caretta caretta)

• Most common sea turtle found in the U.S.
• Up to 4 ft long, 250 pounds
• Relatively slow swimmer but can swim fast when

threatened (sharks and orcas)

• Feeds mostly on crabs, fish, jellyfish, urchins

• Reach sexual maturity at 15-20 years
• Lay 105-120 eggs, incubation is 55-60 days
• Nesting grounds in Florida (about 14,000 each

year), and Masirah island, Oman (about 30,000
each year) (Oman is in middle east near Saudi
Arabia, Indian ocean)

• Status - threatened

Loggerhead

(Caretta caretta)

sea turtles green vs loggerhead and
shark attacks.flv

Green Turtle

(Chelonia mydas)

• Carapace from black to gray to green to brown often with

bold streaks or spots

• Each has distinctive facial markings – like fingerprints –

recognizable by scientists

• 309-506 pounds, 2.6 – 4.3 feet long (largest of hard shells)

• Most widespread species of turtle – found in

North America, South America, Africa, Europe,
and Asia

• Most friendly

is the “honu”
the green
turtles of
Hawaii – swims

with divers

among
coral reefs

Green Turtle

(Chelonia mydas)

• Feeds only on sea grasses and algae as adults
• As juveniles – may feed on jellyfish, small mollusks, and

sponges

• Nest every 2-4 years, sexual maturity is at 20-50 years!
• Lay 75-150 eggs, incubation is 48-70 days
• Status - endangered

Green Turtle

(Chelonia mydas)

Exploited for centuries – for example, back in the

1800s, in just one year, 15,000 green turtles were
imported to England for meat (green turtle soup),
shells, leather

green turtle breathing behavior.flv

Green Turtle

(Chelonia mydas)

Natural Predation

Habitat Destruction

Habitat Destruction

Light Pollution

Net Entanglement and

Fishing Line

Net

Entanglement
and Fishing Line

POACHING

“Accidental” bycatch in shrimp nets

“Accidental” bycatch in shrimp nets

• Marine Scientists in Texas examined 473 turtles

stranded along the Texas coast between 1983 and
1995. They found ingested plastics in more than half of
the turtles sampled.

PLASTIC

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