Sea Turtles

By Jennifer Kennedy, About.com Guide

Loggerhead Sea Turtle (Caretta caretta)

Juan Cuetos/Oceana - www.oceana.org

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Description:

Sea turtles are reptiles that live in a marine or brackish environment. The flippers of sea turtles are long and paddle-like, making them excellent for swimming but poor for walking on land. Another characteristic that helps sea turtles swim easily is their streamlined carapace, or shell.

Classification:

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Subclass: Anapsida
Order: Testudines
Family: Cheloniidae or Dermochelyidae

Sea turtles are classified in the Class Reptilia, Subclass Anapsida and Order Chelonii. There are seven recognized species of sea turtles, six of which are in the Family Cheloniidae (the hawksbill, green, flatback, loggerhead, Kemp's ridley and olive ridley turtles), with only one (the leatherback) in the family Dermochelyidae.

Reproduction:

Sea turtles start their lives in eggs buried in the sand. After a two-month incubation, the young turtles hatch and run to the sea, facing attack by a variety of predators (e.g., birds, crabs, fish) along the way. They drift at sea until they are about a foot long and then, depending on the species, may move closer to shore to feed.

Sea turtles mature at around age 30. The males then spend their whole lives at sea, while females mate with the males at sea and then go to the beach to dig a hole and lay their eggs. Female sea turtles may lay eggs several times during a single season.

Migration:

Sea turtle migrations are extreme - with turtles sometimes traveling thousands of miles between cooler feeding grounds and warm nesting grounds. A leatherback turtle was reported in January 2008 to have undertaken the longest known vertebrate migration - over 12,000 miles (this was later surpassed by the Arctic tern, who was found to make a record 50,000-mile migration. The turtle was tracked by satellite for 674 days from its nesting area in Jamursba-Medi beach in Papua, Indonesia to feeding grounds off Oregon.

As more sea turtles are tracked using satellite tags, we learn more about their migrations and the implications their travels have for their protection - laws protecting sea turtles in one area may be inadequate if those rules don't apply where the turtles migrate.

Sea Turtle Conservation:

All seven species of sea turtles are listed under the Endangered Species Act. Threats to sea turtles today include the harvesting of their eggs for human consumption, entanglement and entrapment in fishing gear, ingestion of litter and coastal development.

Sources:

Defenders of Wildlife. 2008. Sea Turtles (Online). Defenders of Wildlife. Accessed October 26, 2008.
Escambia County Extension. 2008. Types of Sea Turtles (Originally Found Online; as of 8/11, no longer active). University of Florida. Accessed October 27, 2008.
State of the World's Sea Turtles. 2008. Sea Turtles: Ambassadors of the Sea (Online) SWOT: State of the World's Sea Turtles. Accessed October 26, 2008.
Waller, Geoffrey, ed. SeaLife: A Complete Guide to the Marine Environment. Smithsonian Institution Press. Washington, D.C. 1996.