There may be two subspecies,
the Pacific & Indian Ocean Loggerhead, Caretta caretta
gigas, and the Atlantic Loggerhead, Caretta caretta
caretta, but researchers are divided on whether this
is a valid distinction.
Other common names: Loggerhead Turtle, Loggerhead Seaturtle,
Loggerhead, Logrit (Caribbean), Caguama and Cabezona (Latin
America) (Witherington, 2006).
The Loggerhead
Sea Turtle, Caretta
caretta, gets its name from its massive head.
It is among the largest of the hard-shelled sea turtles,
and it has a hard, powerful beak, which it uses to crush
the shells of the crabs and shellfish it feeds on.
The loggerhead is a medium to large size sea turtle with
a weight of 70-170 kg (155 to 375 lbs) and a carapace length
of from 80 to 110 cm (30 to 43 in) (Witherington, 2006).
Its width is about three quarters its length, giving it a
stout appearance. Its color is reddish brown with some darker
streaks, and its shell often becomes home to algae and barnacles,
making it blend in well with the sea bottom where it rests.
Its shoulders are yellowish, and the same yellow color extends
over its entire underside, or plastron. The scales on its
flippers are orange-brown surrounded by yellow skin. It has
two claws on each front flipper, and two pairs of prefrontal
scales, often with one or two intervening scales. It has
5 pairs of lateral scutes, distinguishing it from green sea
turtles and hawksbill turtles, which have four.
Loggerhead Sea Turtles are found in coastal tropical and
subtropical waters throughout the world, and they often venture
into temperate waters to search for food. Some travel as
far north as Newfoundland or as far south as Argentina. Loggerheads
prefer the waters of the continental shelves over islands,
and they often enter estuaries and other mainland shallows.
Large concentrations are found where food sources are abundant,
such as the Chesapeake Bay area estuaries, where horseshoe
crabs congregate in summer, or Baja California, where pelagic
red crabs are found in great numbers.
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| Picture of loggerhead
sea turtle, Caretta
caretta, Bahamas, Caribbean
Sea, Atlantic Ocean. |
Image
#: 003718 |
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Kingdom:
Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Testudines
Suborder: Cryptodera
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Loggerhead Sea Turtles have a varied diet. Their massive head
and powerful jaws allow them to eat mollusks and crustaceans
of all types, and they can easily crush the shells of conchs
and sea snails. They are known to dismantle wooden traps to
get at the lobsters or crabs inside. In addition, they eat
softer animals such as sea cucumbers, sea urchins and soft
corals, and they scavenge fish discarded from fishing vessels.
Juveniles in their pelagic phase feed on whatever floats by,
including algae, plants, fish eggs, snails, shrimp, worms,
jellyfish, dead fish or squid, and more. As they are likely
to eat anything they encounter, they are particularly vulnerable
to discarded floating plastics, which they ingest at their
own peril.
Loggerheads have a wide range of nesting sites and are the
only sea turtles that nest on temperate beaches as well as
tropical ones. The nesting sites with the largest numbers
are Masirah Island, in Oman (30,000 females annually), and
the barrier island beaches of the southeastern U.S., especially
Florida (25,000 females annually).
Loggerheads are known to travel great distances-1,000 miles
or more-to return to their place of birth for mating and
nesting. They mate between March and June, after which the
males quickly depart for their feeding grounds. The females
lay from one to seven clutches of eggs at intervals of two
weeks, each clutch containing about 110 eggs. The eggs incubate
for about two months, after which the 4.5 cm (2 in) brown
or gray hatchlings emerge from their shells and quickly race
to the sea.
Loggerheads spend their juvenile years in a pelagic phase
where they ride the currents of the open ocean. In the Pacific,
this pelagic phase lasts over 15 years. During this phase,
they swim great distances, and tagged individuals from Japan
have been known to reach the coast of California, 9,000 km
(5,600 miles) away. Few marine animals travel as far as the
loggerhead.
In their adult phase, which loggerheads reach at the age
of 15 to 30 years, they stay in close proximity to the continental
shelf. They may live to be 60 years old or older.
During winter months, loggerhead turtles are known to bury
themselves in the muddy sea bottom and lay dormant for periods
of time. Researchers are in dispute over how long this dormant
stage may last, with some saying weeks or months, while others
claiming less than a day.
The IUCN lists the loggerhead as Endangered. In Australia,
they are listed as Highly Endangered, as their numbers there
have decreased by 90% in the last 50 years. Worldwide, nests
are preyed upon by foxes, raccoons and other animals, and
loggerheads are highly vulnerable to commercial fishing nets
and long lines. There are reports of as many as 20,000 loggerhead
deaths annually from long lines in the Mediterranean alone.
In this century, there have been increasing reports of loggerhead
deaths due to parasites as well as diseases caused by biotoxins.
For a diagram helpful in identifying the loggerhead sea
turtle, see: http://marinebio.org/species.asp?id=163
• Loggerhead sea turtle information assembled from published
and on-line sources by Kevin
Miller on Nov. 14, 2006 for Seapics.com.
Sources:
Perrine,
D. Sea Turtles of the World, Voyageur Press, 2003
Ripple,
J. Sea Turtles, Voyageur Press, 1996
Witherington,
B. Sea Turtles, Voyageur Press, 2006
http://marinebio.org/species.asp?id=163 |
