FLORIDA'S FRESHWATER TURTLES
MAIN INDEX | Aquatic
plants, plant management and turtles |
Anatomy and behavior | Turtle species
identification | Conservation |
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Like snakes and alligators, turtles are reptiles. There are about 50 species of turtles in North America. Within their preferred habitats, Florida's freshwater turtles spend a portion of their day basking together (even on top of one another) along sand banks, on floating logs, and on rocks. At other times, these lung-breathing animals can be found discretely floating just below the surface water with only their nostrils protruding above.
Florida's freshwater turtle population is diverse, and different species prefer different environmental conditions such as fast or still currents, muddy or sandy bottoms, and vegetated or open banks. Despite the varied environmental preferences, aquatic turtles in Florida share anatomic similarities (see below); learning the subtle differences facilitates easy identification and appreciation of some of Florida's oldest native denizens.
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(Pseudemys floridana) |
(Pseudemys concinna suwanniensis) |
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| Suwannee Cooters | (Melanistic male, Trachemys scripta scripta) |
(Pseudemys nelsoni) |
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| Gopher tortoise (Gopherus polyphemus ) |
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Some Native Aquatic Plants Used by Freshwater Turtles in Florida
Turtles are known to eat and to prefer the habitats provided by native plants of these
genera: |
AQUATIC PLANTS, PLANT MANAGMENT AND
TURTLES
Turtles, aquatic plants, and aquatic plant management are intimately associated. Turtles eat
aquatic plants, sleep among plants, and hide among plants. Some turtles even mimic aquatic
plants. The spotted shells of the Blanding's turtle and the spotted turtle imitate duckweed,
concealing them from predators, and also concealing them from prey: dragonflies land on the
"duckweed" and are eaten by the lucky turtles.
Turtles can make lake revegetation efforts very difficult: turtles may devour transplanted plants as fast as the plants can grow. Turtles are sometimes in peril in plant management operations, such as when aquatic plant harvesting machines also harvest turtles. In one site during a three-month period, plant harvesting machines also removed and killed about 700 snapping and painted turtles. In another study, the threatened bog turtle was reduced by an invasion of the non-native plant, Pharlaris arundinacea. Other, more natural, perils also exist. For example, redbelly turtles sometimes lay their eggs in alligator nests (made of plant material), as described on our alligators page, and sometimes the redbellies are eaten for doing so...
Many turtles prefer to live amongst certain aquatic plants. Many turtles are omnivores and eat aquatic plants along with aquatic animals. Some turtles are vegetarians and eat only aquatic plants. In one habitat created to help the endangered bog turtle, researchers planted the following plants: Carex stricta, Sagittaria latifolia, Onoclea sensibilis, Juncus effusus, and Scirpus cyperinus.
ANATOMY and BEHAVIOR
The lower portion of the shell is called the plastron and it may be of a different
color or have different markings from the carapace. The shape of the plastron reveals the
sex of the turtle: a male's plastron is concave in order to facilitate mating; the female's
plastron is flat.
The plastron and carapace are covered with hard keratin plates called scutes, which
comprise the mosaic of the shells. If there are ridges on the shell or tail, they are called
keels. Keels and scutes create the hard, armor-like texture of the shell that provides
protection for the turtle. All turtles must spend several hours basking in the sun in order to dry
out the scaley skin on their legs and head and to harden their shell.
The hardened shell provides refuge for a frightened turtle that can easily retract its legs and
head between the plastron and carapace. Unlike seaturtles, freshwater turtles can fold their
neck and retract their head. This ability evolved during the Jurassic Period when turtles
branched into two groups that developed neck retraction separately. Side-necked
turtles are found in the southern hemisphere and withdraw their heads sideways. In contrast,
arch-necked turtles retract their heads in an s-shaped curve. Arch-necked turtles are the
most prolific group and include the box, pond, subaquatic turtles, and tortoises.
The head of an aquatic turtle is sleek and does not have an external ear. Nostrils are
located on top of the snout, enabling the turtle to submerge most of its head beneath the water.
Many turtle species have unique markings on their heads that often enable accurate identification,
even if a turtle is partially submerged.
Beneath the water's surface, turtles spend their day sleeping either along the bottom or in dense
vegetation, or searching for food. Freshwater turtle diets vary as carnivorous species
prey on crayfish, fish, and insects, and vegetarians graze on aquatic plants. (See "Aquatic plants"
above.) Still, many omnivore species are opportunistic, taking advantage of plant and animal food
sources. Although turtles are the only toothless reptile, their sharp beaks catch, cut, and
slice through prey and sever vegetation for food and nest building.
While some species take advantage of lodges previously constructed by muskrats, beavers, and
alligators, most turtles dig their own burrows with their
flat feet, webbed toes, and sharp claws. Turtles are proficient diggers that easily
construct burrows in dry land where all female turtles, even aquatic species, lay their
eggs.
The female turtle's digging abilities outshine her mothering habits: she deposits her eggs, covers
them, and abandons her nest. Sharp-eyed crows, raccoons and other predators sometimes destroy
the turtle nest almost as soon as the mother returns to the water. After incubation, the baby
turtles break out of their eggs and claw their way out of the dirt to the surface. They then
have only their instincts to protect them from the threats of predators such as alligators, birds, snakes, mammals, and humans.
MOST COMMONLY SIGHTED
This turtle is closely related to the Suwannee cooter (Chrysemys concinna
suwanniensis). The Suwannee cooter is listed as a threatened
species; they used to be plentiful but have been killed and eaten, and have also suffered from
diminshed food plants in its favored habitats.
The red-eared slider
(Trachmys scripta elegans) is a subspecies native to the Mississippi River basin.
Introduced through the pet trade, it competes with the red-bellied turtle and breeds with
native yellow bellied sliders.
A smaller, rare relative is the gulf coast smooth softshell turtle
(Trionxy muticus calvatus). This turtle is medium size, to 9 inches long, and lives in
rivers,
streams and lakes.
CONSERVATION
Overdevelopment, water contamination and invasive aquatic plants threaten the future of Florida's
native turtle species. Highway traffic and shooting of basking turtles also take a high toll. In at
least one place, special turtle passages have been constructed to allow turtles to safely cross busy
highways: learn about the Lake Jackson
Ecopassage. Please do not paint a turtle's shell - the paint deforms the shell and may kill
the turtle.
Turtles have managed to endure for more than 200 million years on earth. Conservation and
protection of Florida's fresh waterways will ensure that in Florida, turtles will survive many
more.
Florida Wildlife
Conservation Commission
This page was authored by Sarah Cervone, with contributions from Vic Ramey. Turtle identification provided by Matt Aresco with www.nokuse.org
This project is a collaboration of
Learning a bit about a turtle's anatomy and behavior can help wildlife observers distinguish
one species from another.
Turtles are characterized by a bony shell that provides protection. The top part of the
shell is called a carapace. Noting the shape, color and markings on the carapace is very
useful in identifying the species.
The following list includes 16 of the most commonly sighted aquatic turtles in Florida and
their key identifying characteristics. Species are distinguished most readily by their shells.
Snapping turtles (Chelydra serpentina) grow to 18 inches long and to
20-30 pounds. The snapping turtle has a black or dark dark brown shell. Its large head is
supported by a very long bumpy neck. It catches and eats fish and even birds. They prefer
freshwater habitats with a muddy bottom and rarely leave the water, except to nest. Snapping
turtles are known to bite.
Alligator snapping turtles (Macroclemys temmincki) can grow as large as
31 inches, and to 150 pounds, making it the largest freshwater turtle in the U.S. and one of the
world's largest freshwater turtles. Partly because it is hunted and killed for food (alligator
snapping turtle soup), this animal is a species of special concern.
Alligator snapping turtles may be recognized by their large size, the tall ridge on the back of their
very rough shells, their very large triangular heads (to 9 inches wide!) and their very long tail.
They are seldom seen because they are "bottom walkers" and rarely leave their deep rivers and
canals, except to nest. Alligator snapping turtles have evolved a worm-like "fishing lure" that
dangles from their open mouths which snap shut when a curious fish is lured in. These turtles are
primarily found in the panhandle region of Florida.
(this is a PDF file)
Common mud turtles
(Kinosternon subrubrum) are very small, rarely growing to four inches long. A common
mud turtle has a
black head with two thin yellow lines. Its smooth shell is olive to brown. Males have a spine at the
end of the tail. It will secrete a foul fluid when harrassed. The common mud turtle prefers fresh or
brackish marshes and ponds where it often occupies muskrat lodges. It may also use a beaver
lodge or alligator nest to lay its eggs. Common mud turtles eat insect larvae and other small
aquatic animals.
The striped mud turtle (Kinosternon bauri) grows only to five inches long.
It has three light stripes on a smooth shell. The stripes may fade as the turtle ages. The male has a
spine on the tip of his tail. The striped mud turtle is the most land-loving of the mud turtle group,
and may be found in puddles or small retention ponds. It feeds on snails, insects, dead fish, and
some vegetation. It is also known as the "cow dung cooter" because it is sometimes found
foraging in manure.
Common musk turtles, or stinkpots (Sternotherus odoratus)
average only five inches in length. The common musk turtle has a large pointed black head with
yellow stripes and barbels on the side of the head. It has a smooth brown to grey shell that is
often covered with algae. This turtle exudes a foul musk-like smell when it is harrassed. Although
stinkpots are relatively harmless, aggressive males will bite. Common musk turtles prefer
slow-moving streams and ponds where they may be seen basking on logs and low trees; they
seldom come to shore. They may use a muskrat lodge to nest.
The loggerhead musk turtle (Sternotherus minor) grows to about five
inches long. This turtle has a brown to orange shell that may be patterned with spots or streaks. It
is pink or yellow on the underside. The head has dark spots or stripes. Barbels protrude from the
chin only. The male has a large spine on the tip of the tail. The loggerhead musk turtle may be
found in springs, sinkholes, rivers, and swamps where they crawl along the bottom. Like the
stinkpot, they are extremely odorous.
Chicken turtles (Deirochelys reticularia) can grow to ten inches long.
They have a long, brownish carapace (top shell) with shallow furrows, having yellow net-like
markings. The plastron (bottom shell) is solid yellow. The undersides of the head and legs are
yellow with dark stripes. The rear edge of the shell is smooth. The male is much smaller than the
female. They have very long necks. The chicken turtle prefers shallow water of ditches and ponds
with thick vegetation and may be found basking on logs or wandering on banks. They will bite.
Chicken turtle meat is sometimes eaten in southern states.
The river cooter
(Pseudemys (Chrysemys) concinna) is a species of
special concern. It is about ten inches long and may be the fastest swimming of all turtles in
the U.S. River cooter shells are brown or olive with fine cream-yellow lines. They can be found
basking on logs in springs and rivers with moderate currents. They are quick to dive in the water
when
appraoched. "Cooter" comes from the word, "kuta", which means "turtle" in several African
dialects. River cooters are vegetarian turtles, and feed on native aquatic plants like Najas,
Sagittaria and
Ceratophyllum. River cooter is frequently eaten in the South.
The common cooter (Pseudemys (Chrysemys) floridana)
averages twelve inches long. It is black or brown with yellow stripes. Common cooters prefer
dense aquatic vegetation in ponds, marshes, rivers, and spring runs. They occassionally venture
onto land.
Florida redbelly turtles (Pseudemys (Chrysemys) nelsoni)
grow to about ten inches long. The shell is black with red-brown bars and reddish on the
underside. They have black heads with narrow yellow stripes that shape into an arrow on the
snout.
There is a large notch at the tip of the upper jaw. Florida redbelly turtles feed on aquatic plants in
ponds, marshes,
lakes, and mangrove lined creeks.
The yellow-bellied slider turtle (Trachemys scripta) grows to eight
inches. It is black with yellow bands on each side. Yellow-bellied sliders frequent areas having
soft bottoms and dense vegetation.
The Florida softshell turtle (Trionyx ferox) has a flat grey
to brown head with orange or yellow streaks radiating from a pointed nose. The shell is actually
hard, covered with a leathery skin; the shell edge is soft and there are no horny scales. The male
grows to eight inches long and the female can reach sixteen inches long and longer. Softshell
turtles have very long necks, sharp beaks and ugly tempers - their heads can reach a person
holding them from behind. The largest softshell can weigh 35 pounds. They are hunted and
eaten by some people. They prefer sandy or muddy bottomed lakes, canals, and springs where
they
may be found floating in the water or buried in the bottom. Florida softshell turtles feed on
snails, amphibians, crayfish, and sometimes small birds.
Barbour's map turtle (Graptemys barbouri), a rare species of special concern may be found in the Chipola and
Apalachicola Rivers. Its knobbed shell is olive grey to brown with yellow "U" markings. It has
large yellow or greenish markings behind the eyes. Males can grow to only five inches long;
females may reach twelve inches. Barbour's map turtle eats insects, snails, and crayfish. This
species has been heavily collected, and as a result the population has dwindled.
Alabama map turtle (Graptemys pulchra) males grow to five inches;
females grow to 11 inches long. It has an olive to greenish-brown shell with a black stripe. The
underside is yellow with black seams. The head has large yellow or green spots, and yellow or
orange stripes run down the neck. Males eat insects; females eat snails and clams. The Alabama
map turtle may be found in the western-most tip of the Florida panhandle in creeks of the
Escambia and
Yellow Rivers where it may live to be 50 years old.
The spotted turtle (Clemmys guttata) may grow to five inches long.
This rare turtle has a smooth shell, its legs and head are black with orange or yellow
spots, and its underside is cream-colored. Males have brown eyes, females have orange eyes.
They eat insects, tadpoles and small fish. The spotted turtle may be found basking along slow
moving streams and in shallow woodland ponds in northern Florida during the cooler months, but
they are also seen on land as well.
The eastern box turtle (Terrapene carolina) is primarily terrestrial
although it may be found in wet meadows and floodplains. It grows to nearly nine inches long.
The shell may be tan, brown, yellow, or orange. Males have red eyes and female have yellowish
eyes. Females store sperm and produce several eggs after a single mating. Box turtles feed on
slugs, worms, strawberries, and mushrooms. It can live more than 100 years.
Today, more than 250 species of turtles roam the planet and more than half thrive in
freshwater. Florida's aquatic turtles depend on healthy freshwater springs, rivers, swamps,
marshes, lakes, and ponds to supply native habitats and food sources.
Data is from the APIRS
database.
This page was designed by Becca Hassell.
Photography and graphics are by Ann Murray, Sara Reinhart and Vic Ramey.
the
Center for Aquatic and Invasive Plants, University of Florida, and
the
Bureau of Invasive Plant Management, Florida Department of Environmental
Protection
varamey@nersp.nerdc.ufl.edu
Copyright
2004 University of Florida