HABITAT AND RANGE:
Found primarily in large streams of the
Missouri and Mississippi River systems
from Ohio, Indiana, Illinois, Wisconsin,
Minnesota and the Dakotas southward.
They may also range from extreme
southwestern Alabama, southern and
western Mississippi, Louisiana and
eastern Texas. Typically found in large
rivers and their backwaters, but the
False Map Turtle also occupies lakes,
ponds, sloughs, bayous, oxbows and
occasionally marshes. The False Map
Turtle prefers water with abundant
aquatic vegetation, places to bask and
slow currents, but can be found in
swiftly flowing channels of large
rivers.
PHYSICAL CHARACTERISTICS:
This is a medium to large sized turtle
that grows 5 to 10 inches carapace
length. The shell is dark brown, olive
or black. This turtle gets its name from
the light yellow lines that form a
reticulated or map-like pattern on the
back, but this pattern is usually
obscure on adults. Old females have dark
blotches on the back and plastron. There
is a vertebral keel on the back that is
rather prominent even in adults. The
marginals on the rear of the carapace
are serrated. The plastron is dull
yellow with black lines and swirls. The
head and limbs are black or dark olive.
There are light yellow lines on the head
and limbs. A backwards L is present
behind each eye. There are no large
blotches or spots found on the head and
three lines reach the eye. This
distinguishes False Map Turtles from all
other Map Turtles. Females grow much
larger than the males. Adult males have
long claws on the front feet and a long,
thick tail with the cloacal opening past
the edge of the carapace. The young have
brighter shells and markings, a dark
pattern on the plastron and a pronounced
vertebral keel.
ADAPTATIONS:
Activity varies geographically, but
generally ranges from late March to
mid-October. Emergence from
overwintering (observed in Wisconsin)
occurs in April when the water
temperatures are 4-7 degrees Celsius.
Overwintering sites typically include
muskrat lodges or bank burrows. It is
not uncommon for the False Map Turtle to
be seen basking during winter days in
its more southerly range. It spends the
majority of its day basking in muskrat
lodges, logs, rock piles, sandbars or
stumps. Basking rarely occurs on or near
shore. Basking turtles stretch their
hind limbs, spread the webbing between
the toes and extend the head and
forelimbs. While basking, they are
extremely wary and difficult to
approach. Entrance into the water by one
turtle is usually followed by all those
basking in the general vicinity.
Movement data of this turtle is sparse.
In summer months, most males move into
quiet backwaters to forage. Females also
move into backwaters to forage after
laying their first clutch of eggs.
DIET:
The False Map Turtle is omnivorous,
feeding on mollusks, insects, insect
larvae and plant material. In addition
to consuming the same insects as
females, the males also eat beetles,
flies and fish carrion. In its southern
range, mollusks are the principal
component of the diet.
REPRODUCTION AND DEVELOPMENT:
Mating probably occurs in April and
again in October and November, but has
been observed in a captive male in July.
The nesting season in Wisconsin lasts
from mid-May to late July. First
clutches are usually laid by mid-May to
mid-June. Nests are located in open sand
areas or in areas dominated by low
shrubs. Nests are flask-shaped and dug
with the hind limbs. Two and possibly
three clutches, with 8-22 eggs (varies
with subspecies), are laid per year.
Natural incubation lasts from 60 to 82
days. Gender determination correlates
with incubation temperature.
STATUS IN WILD:
Declining populations in Missouri are
attributed to several factors, including
water pollution, river channelization,
reduction of suitable nesting sites,
siltation and unlawful shooting. In the
past, the pet trade has also influenced
population stability. Commercial
fishermen reported that the species was
more abundant 25 years earlier in the
Missouri and Mississippi Rivers, but has
now become uncommon and all but
eradicated for several river miles below
Kansas City and St. Louis. They
attribute this decline to water
pollution.
