Identification
The river cooter is a large (12-16" carapace) freshwater turtle.
The carapace is rather flat, not highly domed. It is brown or olive with
yellow/cream markings, which vary according to subspecies. The second pleural
scute has a characteristic C-shaped mark. Older males may become very dark
(melanistic) obscuring much of the carapacial design. Hatchlings have a
central keel which disappears with age. The skin is olive to brown, with
yellow stripes. Wide, sometimes dark-edged, stripes under the chin form
an upside-down "Y." The plastron is yellow and is marked with
a large, darker pattern, at least anteriorly. The plastral pattern tends
to fade with age. Males have a broader tail and may have a slightly concave
plastron. Females tend to grow larger than males.
Ernst, Lovich and Barbour (1994) lists five geographically based subspecies.
P. c. concinna (Eastern River Cooter) from Virginia to extreme
northern Florida (The pictured individual is P. c. concinna.) The
stripe down the outside of the hind foot is an identifying characteristic.
P. c. suwanniensis (Suwannee River Cooter) fromwest coast
of peninsular Florida. While marked similarly to the river cooter, it lacks
the stripe on the hind feet. This is one of the larger subspecies.
P. c. hieroglyphica (Hieroglyphic River Cooter) from western
Kentucky, Tennessee, Mississippi, Alabama and western Georgia. The carapace
is intricately patterned and there is an indentation on the bridge. Plastral
pattern is well developed.
P.c. mobilensis (Mobile Bay cooter) from the Gulf watersheds
of the Florida Panhandle to extreme southeastern Texas. It is smaller and
lighter in color than other cooters. Its head stripes are red/orange.
P. c. metteri (Missouri River Cooter) from southwestern Missouri,
southeastern Kansas, south through eastern Oklahoma, eastern Texas, western
Arkansas and western Louisiana. The carapace scutes are marked with vertical,
curved stripes, rather than the usual reticulate pattern. The "C"
may or may not be present. The plastral pattern is dark and clear.
Iverson (1992) did not include P.c. mobilensis, considering it part
of P.c. hieroglyphica. Ernst elevated P. gorzugi to full species
status in an earlier paper, while Iverson includes it as a P. concinna
subspecies.
P. c. gorzugi (Rio Grande Cooter) from Rio Grande basin in
Texas and Mexico and Pecos River basin in New Mexico and adjacent Texas.
It does not have the usual "C" markings, but black and yellow
concentric circles.
In The Wild
Habitat
River cooters live in a wide variety of freshwater and even brackish
locations. Rivers, lakes, ponds and marshes with heavy vegetation provide
ideal habitat. Large webbed feet make the river cooter an excellent swimmer,
capable of negotiating moderately strong river currents of major river systems.
They will collect in large numbers on peninsular floodplains associated
with a river oxbow.
In captivity, cooters need an aquatic habitat, with a dry basking area.
They need a warming light and UVB radiation (from reptile lights or direct
sunshine). As juveniles, they can be kept in a 20- or 30-gallon long tank,
but they will outgrow those accommodations, and need a very large tank or
outdoor pond.
See a sample aquarium suitable for turtles under 6"
long.
Behavior
River cooters enjoy basking on logs or sun-warmed rocks, and are frequently
found in the company of other aquatic basking turtles (sliders and painteds)
sometimes piled up on top of each other. All are quick to slip into the
water if disturbed. Diurnal by nature, these turtles wake with the warming
sun to bask and forage. They can move with surprising speed in the water
and on land. It is not unusual for them to wander from one body of fresh
water to another, but many seem to develope fairly large home ranges, which
they seldom or never leave. They sleep in the water, hidden under vegetation.
While those that live in areas that are quite warm remain active all winter,
river cooters in cooler climes can become dormant during the winter for
up to two months, in the mud, underwater. They do not breathe during this
time of low metabolism, but can utilize oxygen from the water, which they
take in through the cloaca. River cooters perfer to be well hidden under
aquatic plants during the winter dormancy period or while sleeping each
night.
Reproduction
As with the other basking turtles, the males tend to be smaller than
females. Males sport long straight claws which are used as part of the mating
dance. After detecting what may be a pheromone signal while sniffing at
a female's tail, a male river cooter will court a female by swimming above
her, vibrating his long nails and stroking her face. Females have also been
observed doing this to initiate courtship. If the female is receptive, she
will sink to the bottom of the river and allow the male to mount for mating.
Mating takes place in early spring. Nesting usually occurs from May to
June. The female chooses a site with sandy or loamy soil, within 100' of
the river's edge. She looks for a rather open area, with no major obstacles
for the future hatchings to negotiate on their way to the river. The nest
is dug with the hind feet. She lays 10 - 25 or more eggs in one or more
clutches. Eggs are ellipsoidal, approximately 1 1/2" long. Incubation
time is determined by temperature, but averages 90 - 100 days. Hatchlings
generally immerge in August or September. There have been reported instances
of late clutches over-wintering and hatching in the spring. A hatchling
will have a round carapace, about 1 1/2" diameter, that is green with
bright yellow markings. |
Food
While the species is highly herbivorous, river cooters will eat anything,
plant or animal, dead or alive. Diet seems to be determined by available
food items. While some writers feel that these turtles will not eat meat,
predatory behavior has been observed. Although this animal cannot swallow
out of water, it will leave the water to retrieve a tasty bug or worm, returning
to the water to swallow. Cooters will also enthusiatically chase, kill and
eat small fish. They have also been observed eating carrion found along
the river's edge. River cooters have tooth-like cusps in the upper jaw,
probably an adaptation to aid in eating leaves and fibrous vegetation. Their
primary diet would include a wide variety of aquatic plants, and some terrestrial
plants that grow near the water's edge. They will happily take fallen fruits
as well. In captivity, any kind of plant will be eaten, and some "meats",
too. Always keep calcium available in a separate form, such as a cuttlebone,
so that the turtle can self-regulate calcium intake. Click for more general information about feeding turtles.
Longevity
River cooters are faced with loss of habitat, predation by animals, slaughter
on the highways and use as a food source by some people. Hatchlings are
particularly vulnerable. During their overland scramble to the river, many
will be taken by avian and mammal predators. Alligators and muskrats await
them in the water. Some will be taken and sold to pet stores. Populations
are down in some areas, and there have been increasing reports of injured
turtles, but this species as a whole is hardy, and continues to thrive.
These turtles can live 40 years or more.
Sources
Bartlett, R. D. & Bartlett, Patricia P. 1996. Turtles and Tortoises:
A Complete Pet Owner's Manual. Barron's Educational Series, Inc. Hauppauge,
N.Y.
Carr, Archie. 1952. Handbook of Turtles: The Turtles of the United States,
Canada, and Baja California. Cornell University Press. Ithaca, N.Y.
Ernst, Carl H. & Barbour, Roger W. 1989. Turtles of the World. Smithsonian
Institution Press. Washington, D.C.
Ernst, C. H., Lovich, Jeffrey E. & Barbour, R. W. 1994. Turtles of
the United States and Canada. Smithsonian Institution Press. Washington,
D.C.
Iverson, John B. 1992. A Revised Checklist with Distribution Maps of
the Turtles of the World. Earlham College. Privately Published. Richmond,
Indiana.
Pritchard, P. C. H. 1972. Encyclopedia of Turtles. T. F. H. Publications.
Neptune. N.J.
Smith, Hobart M. & Brodie Jr., Edmund D. 1982. A Guide to Field Identification:
Reptiles of North America. Golden Press. New York, N.Y. |
