Sea survivors

Sea turtles have navigated the oceans since the time of the dinosaurs more than 100 million years ago. Today all seven species are under threat at every life stage because of human activities, from accidental capture in fishing nets to overharvesting of eggs and widespread plastic pollution.

CONSERVATION STATUS

Critically endangered

Endangered

Vulnerable

Insufficient data

PRIMARY ADULT DIET

Invertebrate

Marine plant

Horseshoe crab

Sponge

Crustacean

Mollusk

Fish

Hard shell

Six of the seven species have hard shells fused to their ribs and overlaid with keratin scutes. They also have claws on their flippers.

Illustrations in approximate, relative scale

Shell length

4 ft (max)

Maximum diving depth

Green

Chelonia mydas

Named for a layer of green fat under their shell, green turtles start as omnivores before turning into herbivores.

500 ft

Diet

Nesting

area

Range

Population at

highest risk

NORTH

EUROPE

AMERICA

ASIA

ATLANTIC

OCEAN

PACIFIC

AFRICA

OCEAN

EQUATOR

SOUTH

INDIAN

PACIFIC

AMER.

OCEAN

OCEAN

AUS.

ANTARCTICA

3.5 ft

Loggerhead

Caretta caretta

The most abundant sea turtle in the U.S. is named for its giant head. Its strong jaws can crack conch shells.

585 ft

2.1 ft

Kemp’s ridley

Lepidochelys kempii

Accidental capture and egg overharvesting have made the smallest sea turtle the world’s most threatened.

160 ft

3 ft

Hawksbill

Eretmochelys imbricata

Hawksbills’ intricately

patterned, translucent scutes have long been used to decorate jewelry and luxury items.

300 ft

2.3 ft

Olive ridley

Lepidochelys olivacea

The most abundant species exits the sea en masse to nest, a safety-in-numbers strategy against predators.

835 ft

3.1 ft

flatback

Natator depressus

The flatback makes the shortest migration: around Australian waters. It has a nearly flat body with flared edges.

200 ft

flexible shell

Leatherbacks are the only living species with unfused ribs, rubbery skin over layers of connective tissue, and a flexible shell of bony plates.

6 ft

leatherback

Dermochelys coriacea

The largest and deepest diving turtle makes the longest migrations and can weigh up to 2,000 pounds.

4,000 ft

Archelon (extinct)

This giant that roamed the seas 75 million years ago had unfused ribs, like its close relative, the modern leatherback.

FERNANDO G. BAPTISTA, JOHN KAPPLER, DIANA MARQUES, EVE CONAnT, and Taylor Maggiacomo, NGM STAFF; mesa schumacher. SOURCES: Jeanette Wyneken, Florida Atlantic University; Brian Hutchinson, Roderic Mast, Oceanic Society. MAP SOURCES: SCOTT BENSON, SOUTHWEST FISHERIES SCIENCE CENTER, NOAA; State of the World’s Sea Turtles (SWOT), OBIS-SEAMAP

Read the full story

Sea survivors

Sea turtles have navigated the oceans since the time of the dinosaurs more than 100 million years ago. Today all seven species are under threat at every life stage because of human activities, from accidental capture in fishing nets to overharvesting of eggs and widespread plastic pollution.

CONSERVATION STATUS

PRIMARY ADULT DIET

Invertebrate

Marine plant

Horseshoe crab

Sponge

Crustacean

Mollusk

Fish

Critically endangered

Endangered

Vulnerable

Insufficient data

Hard shell

Six of the seven species have hard shells fused to their ribs and overlaid with keratin scutes. They also have claws on their flippers.

Illustrations in approximate, relative scale

Interlocking scutes prevent water loss and cover flattened, fused ribs that separate at the tips.

All sea turtles have glands around the eyes to remove excess salt from their bodies.

Scute

1 in

Rib

Brain

Ribs

Lungs

Esophagus

Stomach

Liver

Fat

The green turtle’s serrated beak helps tear marine plants.

Shell length

4 ft (maximum)

Claw

Green

Chelonia mydas

Maximum diving depth

Diet

Named for a layer of green fat under their shell, green turtles start as omnivores before turning into herbivores.

500 ft

NORTH

Nesting

area

EUROPE

AMERICA

ASIA

ATLANTIC

OCEAN

PACIFIC

AFRICA

OCEAN

EQUATOR

Range

SOUTH

PACIFIC

INDIAN

AMER.

OCEAN

OCEAN

AUS.

Population at

highest risk

ANTARCTICA

Scute

3.5 ft

Loggerhead

Caretta caretta

The most abundant sea turtle in the U.S. is named for its giant head. Its strong jaws can crack conch shells.

585 ft

2.1 ft

Kemp’s ridley

Lepidochelys kempii

Accidental capture and egg overharvesting have made the smallest sea turtle the world’s most threatened.

160 ft

The hawksbill is the only turtle with overlapping scutes and serrated edges on its shell.

Scute

3 ft

Hawksbill

Eretmochelys imbricata

Hawksbills’ intricately patterned, translucent scutes have long been used to decorate jewelry and luxury items.

300 ft

2.3 ft

Olive ridley

Lepidochelys olivacea

The most abundant species exits the sea en masse to nest, a safety-in-numbers strategy against predators.

835 ft

Adult males can be identified by their long tails, which hold sex organs.

Female

3.1 ft

flatback

Natator depressus

The flatback makes the shortest migration: around Australian waters. It has a nearly flat body with flared edges.

200 ft

flexible shell

Leatherbacks are the only living species with unfused ribs, rubbery skin over layers of connective tissue, and a flexible shell of bony plates.

Bone

Skin

Migration cue

Pale skin lets light into the pineal gland, which can track day length and spur migration.

Waxy skin covers a shell of coin-size bony plates that can withstand the pressure of deep dives.

Fat

3 in

Salt

glands

Brain

Ribs

Lungs

Stomach

Liver

Slippery diet

A long, barbed esophagus traps jellyfish and keeps them moving into the stomach.

6 ft

Transferring heat

Blood flowing to flippers warms returning cold blood, maintaining a warmer core than hard-shell turtles have.

Artery

warm blood

Vein

cool blood

leatherback

Dermochelys coriacea

The largest and deepest diving turtle makes the longest migrations and can weigh up to 2,000 pounds.

4,000 ft

Archelon (extinct)

This giant that roamed the seas 75 million years ago had unfused ribs, like its close relative, the modern leatherback.

FERNANDO G. BAPTISTA, JOHN KAPPLER, DIANA MARQUES, EVE CONAnT, and Taylor Maggiacomo, NGM STAFF; mesa schumacher. SOURCES: Jeanette Wyneken, Florida Atlantic University; Brian Hutchinson, Roderic Mast, Oceanic Society. MAP SOURCES: SCOTT BENSON, SOUTHWEST FISHERIES SCIENCE CENTER, NOAA; State of the World’s Sea Turtles (SWOT), OBIS-SEAMAP

Read the full story

Sea survivors

Sea turtles have navigated the oceans since the time of the dinosaurs more than 100 million years ago. Today all seven species are under threat at every life stage because of human activities, from accidental capture in fishing nets to overharvesting of eggs and widespread plastic pollution.

CONSERVATION STATUS

PRIMARY ADULT DIET

Invertebrate

Marine plant

Horseshoe crab

Sponge

Crustacean

Mollusk

Fish

Critically endangered

Endangered

Vulnerable

Insufficient data

Hard shell

Six of the seven species have hard shells fused to their ribs and overlaid with keratin scutes. They also have claws on their flippers.

Illustrations in approximate, relative scale

Interlocking scutes prevent water loss and cover flattened, fused ribs that separate at the tips.

Scute

All sea turtles have glands around the eyes to remove excess salt from their bodies.

1 in

Rib

Brain

Ribs

Lungs

Esophagus

Stomach

Liver

The green turtle’s serrated beak helps tear marine plants.

Fat

Shell length

4 ft (maximum)

Claw

Green

Chelonia mydas

Diet

Maximum diving depth

NORTH

Nesting

area

EUROPE

AMERICA

ASIA

ATLANTIC

OCEAN

PACIFIC

AFRICA

OCEAN

EQUATOR

Named for a layer of green fat under their shell, green turtles start as omnivores before turning into herbivores.

Range

SOUTH

PACIFIC

INDIAN

AMER.

OCEAN

OCEAN

AUS.

500 ft

Population at

highest risk

ANTARCTICA

Front flippers act as wings for propulsion. Rudder-like hind feet stabilize and steer.

Scute

3.5 ft

Loggerhead

Caretta caretta

The most abundant sea turtle in the U.S. is named for its giant head. Its strong jaws can crack conch shells.

585 ft

2.1 ft

Kemp’s ridley

Lepidochelys kempii

Accidental capture and egg overharvesting have made the smallest sea turtle the world’s most threatened.

160 ft

The hawksbill is the only turtle with overlapping scutes and serrated edges on its shell.

Scute

3 ft

Hawksbill

Eretmochelys imbricata

Hawksbills’ intricately patterned, translucent scutes have long been used to decorate jewelry and luxury items.

300 ft

2.3 ft

Olive ridley

Lepidochelys olivacea

The most abundant species exits the sea en masse to nest, a safety-in-numbers strategy against predators.

835 ft

Adult males can be identified by their long tails, which hold sex organs.

Female

3.1 ft

flatback

Natator depressus

The flatback makes the shortest migration: around Australian waters. It has a nearly flat body with flared edges.

200 ft

flexible shell

Leatherbacks are the only living species with unfused ribs, rubbery skin over layers of connective tissue, and a flexible shell of bony plates.

Bone

Skin

Waxy skin covers a shell of coin-size bony plates that can withstand the pressure of deep dives.

Migration cue

Pale skin lets light into the pineal gland, which can track day length and spur migration.

Fat

3 in

Salt

glands

Brain

Lungs

Stomach

Liver

6 ft

Slippery diet

A long, barbed esophagus traps jellyfish and keeps them moving into the stomach.

Transferring heat

Blood flowing to flippers warms returning cold blood, maintaining a warmer core than hard-shell turtles have.

Artery

warm blood

Vein

cool blood

leatherback

Dermochelys coriacea

The largest and deepest diving turtle makes the longest migrations and can weigh up to 2,000 pounds.

4,000 ft

Archelon (extinct)

This giant that roamed the seas 75 million years ago had unfused ribs, like its close relative, the modern leatherback.

FERNANDO G. BAPTISTA, JOHN KAPPLER, DIANA MARQUES, EVE CONAnT, and Taylor Maggiacomo, NGM STAFF; mesa schumacher. SOURCES: Jeanette Wyneken, Florida Atlantic University; Brian Hutchinson, Roderic Mast, Oceanic Society. MAP SOURCES: SCOTT BENSON, SOUTHWEST FISHERIES SCIENCE CENTER, NOAA; State of the World’s Sea Turtles (SWOT), OBIS-SEAMAP

Read the full story