Download lesson one: species and distribution

LESSON ONE: SPECIES AND DISTRIBUTION
TURTLE FACTS:
Sea turtles date back 110 million years to the early Cretaceous period. Today, there are
seven species and all but two are found in every ocean basin around the world. The
seven species that live in our oceans are the loggerhead (Caretta caretta), leatherback
(Dermochelys coriacea), hawksbill (Eretmochelys imbricata), green (Chelonia mydas),
olive ridley (Lepidochelys olivacea), Kemp’s ridley (Lepidochelys kempii), and flatback
(Natator depressus). These seven turtles fall into two families: Dermochelyidae, which
consists of the leatherback (Dermochelys coriacea) and Cheloniidae, which consists of
the remaining six hard-shelled species. Six of the seven species are listed as vulnerable,
endangered, or critically endangered according to the International Union for
Conservation of Nature (IUCN).
LEATHERBACK:
The leatherback is the largest of all sea turtles and one of the largest reptiles on Earth
(www.seeturtles.org)! They can be over 6 feet long and weigh more than 1500 lbs.
Leatherbacks do not have a hard shell like, unlike all other sea turtles; instead they have
leathery like skin which allows them to dive deep. They have long migrations and dive
deep in order to eat jellyfish. The longest leatherback migration was 13,000 kilometers
in one direction.
LOGGERHEAD:
Loggerheads can be found in large numbers in the United States. This species is known
for its large head and jaws that help them eat clams, crabs, fish, and snails. Loggerheads
are also highly migratory.
HAWKSBILL:
The hawksbill is named for its large pointy beak, which facilitates eating sponges.
Hawksbills are the only marine animals whose diet consists mostly of sponges found in
coral reefs, therefore this turtle is important to coral reef ecosystems and health.
GREEN:
The green turtle is the turtle found most around the world. The name for this turtle
comes from the green color of its body fat mostly due to the fact that their diet consists
of sea grass.
KEMP’S RIDLEY:
The Kemp’s ridley is the smallest of all sea turtles and is nests only in the Gulf of Mexico.
Its diet consists of crustaceans, mollusk as well as jellyfish. Kemp’s ridleys can nest in
mass aggregations known as arribadas and they are one of two species that commonly
nest during the day (nesting is usually at night when there is less chance of predation).
OLIVE RIDLEY:
Olive ridleys are best known for their arribadas. This phenomenon is when hundreds of
thousands of turtles come ashore to nest simultaneously during the same 3-7 day
period every month. Olive ridleys are thought to have the highest populations globally.
Their diet consists of crustaceans, mollusk as well as jellyfish.
FLATBACK:
The flatback is only found along the northern coast of Australia. Their diet consists of
crustaceans, mollusk as well as jellyfish. Flatbacks share waters with saltwater crocodiles,
which makes it difficult to study the species. Therefore, the flatback is the least studies
species.
DISTRIBUTION:
This map shows that sea turtles travel long distances all over the world and they are a
shared resource among many countries. Harmful practices in one country can
jeopardize conservation and mitigation efforts to protect turtles and their habitats in
another country. Therefore, the challenge lies in managing across countries and
throughout many ocean habitats, the threats at each life cycle (next lesson), and the
quality and amount of resources in a given habitat.