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Why Leatherbacks & Sea Turtles Matter

Leatherbacks and other sea turtles are magnificent creatures. Sea turtles are ancient creatures celebrated in creation myths belonging to diverse cultures around the world. The world’s seven species of sea turtles all live in the oceans and nest onshore. Every species has evolved to survive in particular habitats and each sea turtle plays a part in keeping marine ecosystems healthy.

Ancient Animals

Sea turtles swam the oceans when dinosaurs roamed the earth 110 million years ago. Early explorers marveled at the abundance of sea turtles. They fished turtles heavily for their meat, which sustained sailors during ocean voyages. With the spread of human development around the globe, sea turtle numbers have dropped to 0.1 percent of their historical abundance. Now these ancient reptiles confront new threats, like pollution, industrial fishing, climate change, and large-scale coastal development.

Historical engravings of leatherbacks leave something to be desired as to the accuracy of the representation. However, they teach us that humans have been observing leatherbacks for hundreds of years.

FCIT | Private collection of Roy Winkelman

Sea turtles help to sustain the health, productivity and biodiversity of marine ecosystems.

Scientists describe sea turtles as keystone species in recognition of the roles they play to support ecosystem function and balance. Leatherbacks keep jellyfish populations in check and hawskbills prevent sponges from outcompeting corals.

As the largest, deepest-diving and farthest ranging sea turtles, leatherbacks are a flagship species for the other six species of sea turtles.

Like other sea turtles, leatherbacks are negatively impacted by unsustainable beachfront development at nesting sites and destructive fishing practices. Charismatic leatherbacks also raise awareness for animals facing similar threats like albatross, which also die from ingesting plastic or entanglement in longlines.

Scientists say a leatherbacks detects seasonal changes through a "third eye" on the top of its head.

© Jason Bradley | BradleyPhotographic.com

Leatherbacks can hold their breath for up to 85 minutes, but fishermen set longlines for 10+ hours.

© Doug Perrine | SeaPics.com

Habits and Habitats

There are seven species of sea turtle. All sea turtles share common life history characteristics and even face common threats from nest disturbance, development, fishing, pollution and climate change. 

Nearly all sea turtle species are endangered. Each population is classified by conservation status: vulnerable, endangered, or critically endangered. Endangered means the species is in danger of extinction and critically endangered indicates a high risk of extinction. A population is determined vulnerable when it shows a high probability of becoming a species at risk of extinction. 

Leatherback

Dermochelys coriacea

Scientists describe sea turtles as keystone species in recognition of the roles they play to support ecosystem function and balance. Leatherbacks keep jellyfish populations in check and hawskbills prevent sponges from outcompeting corals.

Leatherbacks are the largest sea turtles. Males can reach up to 8.5 ft (2.6m) and 2000 lbs (900 kg). Unlike other sea turtles, leatherbacks have a flexible, rubbery carapace that allows them to dive deeper than 4100 feet (1250 meters). Leatherbacks nest on tropical beaches and are found in all the world’s oceans except the Arctic and Antarctic. The leatherback’s esophagus is extra-long and lined with spines to facilitate digestion of jellyfish.

Global Status: Vulnerable / Eastern Pacific: Critically Endangered

Shell length: 52-75 inches (132-190 cm)

Weight: 550-1100 lbs (250-500 kg)

© Dawn Witherington | DrawnbyDawn.com

Green turtle

Chelonia mydas

Green turtles have small rounded heads and a smooth carapace. Ranging throughout the tropical and subtropical Atlantic, Pacific and Indian Oceans, they eat sea grasses and rooted algae. Green turtles received their name due to their diet, which gives their fat a greenish color. The East Pacific green turtle subspecies (Chelonia mydas agassizii) is often called the black turtle, due to its somewhat darker appearance.

Status: Endangered

Shell length: 32-48 inches (81-122 cm)

Weight: 144-450 lbs (65-204 kg)

© Dawn Witherington | DrawnbyDawn.com

Loggerhead

Caretta caretta

Loggerheads have large heads with powerful jaws for crushing crabs, mollusks and other marine invertebrates. They nest on subtropical beaches and forage in estuaries, along continental shelves and in pelagic habitats. Loggerheads populations are declining rapidly and fewer turtles are returning to lay eggs at nesting beaches.

Status: Endangered

Length: 34-49 inches (85-124 cm) 

Weight: 176-440 lbs (80-200 kg)

© Dawn Witherington | DrawnbyDawn.com

Hawksbill

Eretmochelys imbricata

Hawksbills have narrow heads and hooked beaks for eating sponges. They nest on tropical beaches and are mostly found near coral reef habitats. The hawksbill’s carapace has thick overlapping scutes with beautiful coloration, which made these turtles prime hunting targets for tortoiseshell” trinkets.

Status: Critically endangered

Length: 30-35 inches (76-88 cm) 

Weight: 95-165 lbs (43-75 kg)

© Dawn Witherington | DrawnbyDawn.com

Olive Ridley

Lepidochelys olivacea

Olive ridleys are considered the most abundant sea turtle, although the current global population is only 0.2% of the species’ historical abundance. Females often nest together in large aggregations, known as arribadas, of up to 200,000 turtles at once. Olive ridleys forage along drift lines on a number of species, including crabs, jellyfish, clams, snails and some algae.

Status: Vulnerable

Length: 22-30 inches (55-75 cm)

Weight: 85-95 lbs (38-43 kg)

© Dawn Witherington | DrawnbyDawn.com

Kemp’s Ridley

Lepidochelys kempii

Kemp’s ridleys are limited to the Gulf of Mexico and North Atlantic, where they feed on crabs, clams and snails in shallow coastal waters. Kemp’s ridleys are also known to nest in arribadas, but only during daylight hours. A successful “headstart” program gave the species a chance at recovery after the population in the Gulf of Mexico was severely reduced by incidental take from shrimp trawling.

Status: Critically endangered

Length: 25-30 inches (62-75 cm) 

Weight: 80-100 lbs (36-45 kg)

© Dawn Witherington | DrawnbyDawn.com

Flatback

Natator depressus

Flatback turtles received their name for their flattened shell. Their range is limited to the tropical waters of Australia, where they feed in shallow waters on jellyfish, sea pens and other soft-bodied invertebrates. Although the flatback’s nesting beaches are remote and undeveloped, feral pigs are known to disturb nests. Flatbacks also face significant threats from shrimp trawling and other fishing activities.

Status: Data deficient

Length: 30-39 inches (76-99 cm) 

Weight: 154-198 lbs (70-90 kg)

© Dawn Witherington | DrawnbyDawn.com

Life Cycle of Leatherbacks

The leatherback life cycle begins with a female turtle laying eggs on a nesting beach. Females stay close to shore in “internesting habitats” for 3-4 months and make repeated visits at 10-day intervals to lay eggs. Adult females depart for pelagic habitats to forage and remain there for an average “remigration interval” of 2-5 years until they return to nest once again.

About 55-60 days after the female lays eggs, hatchling turtles emerge from their nests, head to the sea and follow ocean currents to pelagic nursery habitats, where they search for food and seek refuge from predators. Scientists refer to this time period as “the lost years”, since finding hatchlings and juveniles to study in the open ocean is difficult.

After 15-25 years leatherbacks reach maturity. Mature female turtles return to their natal beaches for nesting, but adult male turtles live entirely at sea.

Leatherbacks nest on beaches with vegetation and slopes that limit the distance to dry sand.

© Kip Evans Photography | Mission Blue

Life Cycle of Leatherbacks

Female leatherbacks usually lay their eggs at night. Nesting turtles may decide not to nest if there are too many lights onshore. Those that come ashore seek nesting sites free of debris (tree limbs). If the turtle does not find a suitable site for her nest, she may return to the ocean without laying.

Leatherbacks carve out an egg chamber about 75 centimeters (inches) deep in the sand, where they deposit 65-115 eggs. (East Pacific leatherbacks are known to lay fewer eggs than their counterparts in the Atlantic.) Only 85 percent of these eggs are viable, as some have no yolk to develop into an embryo.

A leatherback can lay 7 to 11 individual nests per season, laying a new nest every 10 days. Between nesting seasons, females will spend 3-4 years feeding to build up enough energy to nest again. Older females typically lay more nests with more eggs than turtles that have recently reached maturity.

The sex of turtle eggs is determined by the temperature of the nest. During the middle third of incubation (days 20-40) the temperature within the nest determines the ratio of males to females; warmer temperatures mean more females while cooler temperatures yield more males.

After an incubation period of 60 days the eggs will begin to hatch. The hatchling turtles must emerge from the nest and make their way to the ocean. Ten percent of hatchlings will be eaten by seabirds, crabs, reptiles and mammals on the beach. Only 25 percent of hatchlings will make it through their first few days in the ocean. Just 6 percent of hatchlings will survive their first year.

A leatherback hatchling swims in the ocean for the first time.
Images by Jason Bradley and Brian Skerry.
An embryonic leatherback
Images by Jason Bradley and Brian Skerry.
Fresh from the egg, leatherback hatchlings face predation by birds, crabs and unleashed pets
Images by Jason Bradley and Brian Skerry.
Leatherback hatchlings emerge from the nest together t reduce offtake by predators
Images by Jason Bradley and Brian Skerry.
Leatherback hatchlings are prey for birds and crabs on the beach
Images by Jason Bradley and Brian Skerry.
Hatchlings need to move fast to avoid predators
Images by Jason Bradley and Brian Skerry.
After hatching, male leatherbacks will spend their entire lives at sea
Images by Jason Bradley and Brian Skerry.
A leatherback hatchling swims in the ocean for the first time
Images by Jason Bradley and Brian Skerry.

Foraging

Although leatherback turtles nest in the tropics, they principally feed (also called foraging) in cold waters far from the equator, such as those of Chile, California, Canada, northern Europe, southern Africa and New Zealand. These areas are most abundant in jellyfish, which are a primary food source for leatherback turtles.

Scientists divide leatherbacks into seven subpopulations: East Pacific Ocean, West Pacific Ocean, Northwest Atlantic Ocean, Southeast Atlantic Ocean, Southwest Atlantic Ocean, Northeast Indian Ocean, and Southwest Indian Ocean.

Leatherbacks play an important role in marine ecosystems by keeping jellyfish populations in check.

© Brian Skerry | BrianSkerry.com

We do not know how leatherback turtles navigate the great distances between their feeding grounds and their nesting beaches. However, we do know that turtles follow common paths between nesting and feeding habitats. Scientists refer to these paths as migration corridors.

Why Leatherbacks & Sea Turtles Matter

Leatherbacks and other sea turtles are magnificent creatures. Sea turtles are ancient creatures celebrated in creation myths belonging to diverse cultures around the world. The world’s seven species of sea turtles all live in the oceans and nest onshore. Every species has evolved to survive in particular habitats and each sea turtle plays a part in keeping marine ecosystems healthy.

Ancient Animals

Sea turtles swam the oceans when dinosaurs roamed the earth 110 million years ago. Early explorers marveled at the abundance of sea turtles. They fished turtles heavily for their meat, which sustained sailors during ocean voyages. With the spread of human development around the globe, sea turtle numbers have dropped to 0.1 percent of their historical abundance. Now these ancient reptiles confront new threats, like pollution, industrial fishing, climate change, and large-scale coastal development.

Historical engravings of leatherbacks leave something to be desired as to the accuracy of the representation. However, they teach us that humans have been observing leatherbacks for hundreds of years.

FCIT | Private collection of Roy Winkelman

Sea turtles help to sustain the health, productivity and biodiversity of marine ecosystems.

Scientists describe sea turtles as keystone species in recognition of the roles they play to support ecosystem function and balance. Leatherbacks keep jellyfish populations in check and hawskbills prevent sponges from outcompeting corals.

As the largest, deepest-diving and farthest ranging sea turtles, leatherbacks are a flagship species for the other six species of sea turtles.

Like other sea turtles, leatherbacks are negatively impacted by unsustainable beachfront development at nesting sites and destructive fishing practices. Charismatic leatherbacks also raise awareness for animals facing similar threats like albatross, which also die from ingesting plastic or entanglement in longlines.

Scientists say a leatherbacks detects seasonal changes through a "third eye" on the top of its head.

© Jason Bradley | BradleyPhotographic.com

Leatherbacks can hold their breath for up to 85 minutes, but fishermen set longlines for 10+ hours.

© Doug Perrine | SeaPics.com

Habits and Habitats

There are seven species of sea turtle. All sea turtles share common life history characteristics and even face common threats from nest disturbance, development, fishing, pollution and climate change. 

Nearly all sea turtle species are endangered. Each population is classified by conservation status: vulnerable, endangered, or critically endangered. Endangered means the species is in danger of extinction and critically endangered indicates a high risk of extinction. A population is determined vulnerable when it shows a high probability of becoming a species at risk of extinction. 

Leatherback

Dermochelys coriacea

Scientists describe sea turtles as keystone species in recognition of the roles they play to support ecosystem function and balance. Leatherbacks keep jellyfish populations in check and hawskbills prevent sponges from outcompeting corals.

Leatherbacks are the largest sea turtles. Males can reach up to 8.5 ft (2.6m) and 2000 lbs (900 kg). Unlike other sea turtles, leatherbacks have a flexible, rubbery carapace that allows them to dive deeper than 4100 feet (1250 meters). Leatherbacks nest on tropical beaches and are found in all the world’s oceans except the Arctic and Antarctic. The leatherback’s esophagus is extra-long and lined with spines to facilitate digestion of jellyfish.

Global Status: Vulnerable / Eastern Pacific: Critically Endangered

Shell length: 52-75 inches (132-190 cm)

Weight: 550-1100 lbs (250-500 kg)

© Dawn Witherington | DrawnbyDawn.com

Green turtle

Chelonia mydas

Green turtles have small rounded heads and a smooth carapace. Ranging throughout the tropical and subtropical Atlantic, Pacific and Indian Oceans, they eat sea grasses and rooted algae. Green turtles received their name due to their diet, which gives their fat a greenish color. The East Pacific green turtle subspecies (Chelonia mydas agassizii) is often called the black turtle, due to its somewhat darker appearance.

Status: Endangered

Shell length: 32-48 inches (81-122 cm)

Weight: 144-450 lbs (65-204 kg)

© Dawn Witherington | DrawnbyDawn.com

Loggerhead

Caretta caretta

Loggerheads have large heads with powerful jaws for crushing crabs, mollusks and other marine invertebrates. They nest on subtropical beaches and forage in estuaries, along continental shelves and in pelagic habitats. Loggerheads populations are declining rapidly and fewer turtles are returning to lay eggs at nesting beaches.

Status: Endangered

Length: 34-49 inches (85-124 cm) 

Weight: 176-440 lbs (80-200 kg)

© Dawn Witherington | DrawnbyDawn.com

Hawksbill

Eretmochelys imbricata

Hawksbills have narrow heads and hooked beaks for eating sponges. They nest on tropical beaches and are mostly found near coral reef habitats. The hawksbill’s carapace has thick overlapping scutes with beautiful coloration, which made these turtles prime hunting targets for tortoiseshell” trinkets.

Status: Critically endangered

Length: 30-35 inches (76-88 cm) 

Weight: 95-165 lbs (43-75 kg)

© Dawn Witherington | DrawnbyDawn.com

Olive Ridley

Lepidochelys olivacea

Olive ridleys are considered the most abundant sea turtle, although the current global population is only 0.2% of the species’ historical abundance. Females often nest together in large aggregations, known as arribadas, of up to 200,000 turtles at once. Olive ridleys forage along drift lines on a number of species, including crabs, jellyfish, clams, snails and some algae.

Status: Vulnerable

Length: 22-30 inches (55-75 cm)

Weight: 85-95 lbs (38-43 kg)

© Dawn Witherington | DrawnbyDawn.com

Kemp’s Ridley

Lepidochelys kempii

Kemp’s ridleys are limited to the Gulf of Mexico and North Atlantic, where they feed on crabs, clams and snails in shallow coastal waters. Kemp’s ridleys are also known to nest in arribadas, but only during daylight hours. A successful “headstart” program gave the species a chance at recovery after the population in the Gulf of Mexico was severely reduced by incidental take from shrimp trawling.

Status: Critically endangered

Length: 25-30 inches (62-75 cm) 

Weight: 80-100 lbs (36-45 kg)

© Dawn Witherington | DrawnbyDawn.com

Flatback

Natator depressus

Flatback turtles received their name for their flattened shell. Their range is limited to the tropical waters of Australia, where they feed in shallow waters on jellyfish, sea pens and other soft-bodied invertebrates. Although the flatback’s nesting beaches are remote and undeveloped, feral pigs are known to disturb nests. Flatbacks also face significant threats from shrimp trawling and other fishing activities.

Status: Data deficient

Length: 30-39 inches (76-99 cm) 

Weight: 154-198 lbs (70-90 kg)

© Dawn Witherington | DrawnbyDawn.com

Life Cycle of Leatherbacks

The leatherback life cycle begins with a female turtle laying eggs on a nesting beach. Females stay close to shore in “internesting habitats” for 3-4 months and make repeated visits at 10-day intervals to lay eggs. Adult females depart for pelagic habitats to forage and remain there for an average “remigration interval” of 2-5 years until they return to nest once again.

About 55-60 days after the female lays eggs, hatchling turtles emerge from their nests, head to the sea and follow ocean currents to pelagic nursery habitats, where they search for food and seek refuge from predators. Scientists refer to this time period as “the lost years”, since finding hatchlings and juveniles to study in the open ocean is difficult.

After 15-25 years leatherbacks reach maturity. Mature female turtles return to their natal beaches for nesting, but adult male turtles live entirely at sea.

Leatherbacks nest on beaches with vegetation and slopes that limit the distance to dry sand.

© Kip Evans Photography | Mission Blue

Life Cycle of Leatherbacks

Female leatherbacks usually lay their eggs at night. Nesting turtles may decide not to nest if there are too many lights onshore. Those that come ashore seek nesting sites free of debris (tree limbs). If the turtle does not find a suitable site for her nest, she may return to the ocean without laying.

Leatherbacks carve out an egg chamber about 75 centimeters (inches) deep in the sand, where they deposit 65-115 eggs. (East Pacific leatherbacks are known to lay fewer eggs than their counterparts in the Atlantic.) Only 85 percent of these eggs are viable, as some have no yolk to develop into an embryo.

A leatherback can lay 7 to 11 individual nests per season, laying a new nest every 10 days. Between nesting seasons, females will spend 3-4 years feeding to build up enough energy to nest again. Older females typically lay more nests with more eggs than turtles that have recently reached maturity.

The sex of turtle eggs is determined by the temperature of the nest. During the middle third of incubation (days 20-40) the temperature within the nest determines the ratio of males to females; warmer temperatures mean more females while cooler temperatures yield more males.

After an incubation period of 60 days the eggs will begin to hatch. The hatchling turtles must emerge from the nest and make their way to the ocean. Ten percent of hatchlings will be eaten by seabirds, crabs, reptiles and mammals on the beach. Only 25 percent of hatchlings will make it through their first few days in the ocean. Just 6 percent of hatchlings will survive their first year.

A leatherback hatchling swims in the ocean for the first time.
Images by Jason Bradley and Brian Skerry.
An embryonic leatherback
Images by Jason Bradley and Brian Skerry.
Fresh from the egg, leatherback hatchlings face predation by birds, crabs and unleashed pets
Images by Jason Bradley and Brian Skerry.
Leatherback hatchlings emerge from the nest together t reduce offtake by predators
Images by Jason Bradley and Brian Skerry.
Leatherback hatchlings are prey for birds and crabs on the beach
Images by Jason Bradley and Brian Skerry.
Hatchlings need to move fast to avoid predators
Images by Jason Bradley and Brian Skerry.
After hatching, male leatherbacks will spend their entire lives at sea
Images by Jason Bradley and Brian Skerry.
A leatherback hatchling swims in the ocean for the first time
Images by Jason Bradley and Brian Skerry.

Foraging

Although leatherback turtles nest in the tropics, they principally feed (also called foraging) in cold waters far from the equator, such as those of Chile, California, Canada, northern Europe, southern Africa and New Zealand. These areas are most abundant in jellyfish, which are a primary food source for leatherback turtles.

Scientists divide leatherbacks into seven subpopulations: East Pacific Ocean, West Pacific Ocean, Northwest Atlantic Ocean, Southeast Atlantic Ocean, Southwest Atlantic Ocean, Northeast Indian Ocean, and Southwest Indian Ocean.

Leatherbacks play an important role in marine ecosystems by keeping jellyfish populations in check.

© Brian Skerry | BrianSkerry.com

We do not know how leatherback turtles navigate the great distances between their feeding grounds and their nesting beaches. However, we do know that turtles follow common paths between nesting and feeding habitats. Scientists refer to these paths as migration corridors.

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The Leatherback Trust Inc. is a US 501(c)3 non profit organization – EIN 22-3741033