If you are silent and slow as you approach Rainbow Bridge
to cross over Lake
Wapalanne, you may be lucky
enough to see a group of Eastern Painted Turtles basking on a fallen pine tree
that rests, half submerged, in the water.
These turtles, which do not exceed ten inches in length, discovered this
basking spot as soon as the warm spring months arrived. After a winter of hibernating underwater in
the cold mud of Lake
Wapalanne, their sunny
perch is a welcome resting place. It is fitting
that these turtles can be seen from Rainbow
Bridge, because they are
very colorful turtles, named for the yellow, olive, or red borders along the shell;
orange and red marks on the edges of the shell; yellow underside; and red,
orange, and yellow markings on the neck, legs, tail, and face.
Painted turtles, like all turtles, are reptiles, herpetons, or “crawling things.” They belong to the order Chelonia. There are three additional orders of
reptiles, including the Squamata, or lizards and snakes, Crocodilia, and
Rhynchocephalia, which contains only one living genus. Turtles evolved from the ancestor Eunotosaurus africanus, a small animal
that lived in South Africa
about 260 million years ago. This animal
began to develop large, thick ribs, which preceded the formation of the
turtle’s carapace, or shell. 248 million
years ago, Anthodon was a reptile
that developed bony, plated armor, much like the turtle’s shell today. However, the animal that is considered to be
the ancestor of all modern turtles and tortoises is Proganochelys, which lived 220-230 million years ago.
There are more than 300 species of turtles worldwide today,
and each is characterized by its carapace, or the top of the shell; plastron,
or the part of the shell that covers the underside of the turtle and is fused
to the ribs; and the two lateral bridges, which are ligamentous tissues that
connect the carapace and plastron on either side of the turtle. Some turtles are known as soft-shelled
turtles, and these turtles, instead of having a typical carapace made up of
bony plates, actually have a continuous covering of leathery skin on top of the
bones that make up the shell.
The turtle’s bony shell is a calcified structure. It is covered with a thin layer of keratinous
scales, or scutes, which are made up of the same material as our
fingernails. Just as a snake sheds its
skin, the turtle will shed its scutes.
If a turtle’s shell is injured, it has the capacity to repair
itself. The underlying tissue will
calcify and the keratin will reform.
This, however, may take a long time.
Often, the scutes on a turtle’s shell match the substrate of the
environment in which the turtle lives.
This camouflage often provides them with great protection.
Turtles, like all reptiles, are cold-blooded creatures; they
need to absorb heat from their environment to stay warm. To deal with the cold, turtles have many
strategies. Heat generated from muscular
activity, insulation from fat, and the protection from the carapace all allow
the turtle to stay warm. Additionally,
turtles may stay warm by covering themselves with mud, water, sand, or
urine. In the winter, turtles hibernate
to survive the cold months. When it is
too hot, turtles will burrow, take mud or sand baths, and slow their metabolisms
to stay cool.
Turtles have no teeth; instead, they have a beak. They have internal ears that give them
excellent hearing. Turtles are very
sensitive to ground vibrations, so they are difficult to sneak up on, even if
you are being extremely quiet. This is
why the Painted Turtles will plunge into the water as soon as you walk by! Turtles have a poor sense of smell and poor
eyesight; they react more to movement than to shapes. Their heartbeats are much slower than ours,
beating at just about 20 times per minute!
The smallest turtle is the 100mm long speckled tortoise of South Africa. The largest turtle, the leatherback sea
turtle, is 2 meters long! Can you
imagine swimming in the ocean with a turtle that big? While turtles are often found in water, every
species lays its eggs on land, including sea turtles. All species of turtles are long-lived and can
expect to live for half a century or more, with some exceeding 150 years! Most turtles lay eggs that take between 60
and 100 days to incubate, depending on the species and the temperature of the
sand or soil. Of the 330 or so species
of turtles, thirteen live in New Jersey, and eight
live in Sussex County.
Those that live in other parts of the state include the Eastern Mud Turtle,
Northern Diamondback Terrapin, Common Map Turtle, Redbelly Turtle, and Eastern
Spiny Softshell Turtle.
Of all of New
Jersey’s turtles, perhaps the last one that we want
to encounter is the Common Snapping Turtle.
Found swimming in ponds and lakes, lurking in aquatic vegetation, or
basking just beneath the surface of the water, the Snapping Turtle is a turtle
to avoid. With a massive head, strong
jaws, a sharp beak, and long claws, this turtle can cause injury to those who
approach it too closely. An omnivore,
the Snapping Turtle has a varied diet and will eat insects, fish, worms,
amphibians, snakes, other turtles, birds, small mammals, plants, and
algae. About thirty small Snapping Turtles
will hatch from their eggs in late August through October; these babies may one
day reach a size of more than 75 pounds!
Another turtle that can be found swimming in lakes and ponds
is the Common Musk Turtle, also known as the Stinkpot Turtle. This small turtle grows no bigger than five
inches long. It is given its name
because of the foul smell the turtle exudes from its glands when it feels
threatened, just as a skunk does. This
turtle will bask beneath the surface of the water and prefers to walk along the
muddy bottom, where algae will grow on its shell. Also an omnivore, the Musk Turtle eats small
insects, algae, snails, fish eggs, and amphibians.
The Spotted Turtle is another small turtle, growing no more
than five inches long. This turtle has a
black shell with small yellow spots; the turtle also has yellow spots on its
head, neck, and limbs. These spots break
up the outline of the turtle, making it harder for potential predators to see
it; the spots may also appear to be rays of sun reflecting on the surface of
the water. This turtle can be found in
marshes, small creeks, and wet forested areas.
They are omnivores, feeding on insects, algae, aquatic vegetation, small
amphibians, and freshwater crustaceans.
A turtle that we’d rather not see in New Jersey is the Red-eared Slider Turtle. This species is native to the southeastern United States, but it has been introduced to New Jersey, and many
other places, by pet owners who no longer want these turtles as pets. These opportunistic turtles are recognized by
a red band behind each eye. Like the Painted
Turtles, Red-eared Sliders love basking in the sun. They are omnivores and eat snails, crayfish,
insect larvae, tadpoles, small fish, and vegetation. Both Red-eared Sliders and
Painted Turtles tend to be more carnivorous when they are born and eventually
transition to a mostly herbivorous diet as adults.
The least aquatic of all of New Jersey’s turtles is the Eastern Box Turtle,
which prefers upland, forested areas, though it will always be near a source of
water. The genus name for this turtle,
Terrapene, comes from “terrapin,” a word by the Algonquian, a group of
indigenous people who inhabited the northeastern United States. Box Turtles are known for their high, domed
shells that are fit with a hinged plastron; this hinge allows the turtle to
close itself entirely within the shell to keep away from any threats. Young Box Turtles eat insects, worms, slugs,
and snails, while adults are more herbivorous, preferring mushrooms above all
else.
Sadly, two thirds of the world’s turtle species are
threatened or endangered today, due to a multitude of factors including the pet
trade, zoo trade, and the desire for turtle shells and turtle-derived oil,
meat, and fat. New Jersey is home to one threatened
species, the Wood Turtle, and one endangered species, the Bog Turtle. The Wood Turtle was listed as a threatened
species in 1979 after major decreases in its abundance and distribution across
the state were recorded. Habitat loss
and stream degradation have impacted this riparian and wetland-loving turtle. The small Bog Turtle, less than five inches
long, is very elusive, but has become even harder to find due to habitat loss,
pollution, and illegal collecting. If
you find a Bog Turtle in marshes, wet meadows, or fens, that habitat should be
managed in favor of the Bog Turtles by controlling nonnative plant species and
suppressing vegetative succession.
Here at the New Jersey School of Conservation, researchers
from Montclair State
University study the turtles found in Lake Wapalanne. Dr. Lisa Hazard, Dr. Kirsten Monsen-Collar,
and students Tara Snyder, Paola Dolcemascolo, and Linda Araya capture and mark
Common Musk Turtles and Eastern Painted Turtles. They take data on these turtles, including
information on size, sex, and evidence of predation damage or parasites, before
releasing them back into the lake. Why
take this preliminary data? The
researchers are hoping that gaining a sense of the population and the behavior
of turtles will lead to more rigorous research questions. Possible research projects for the future include
exploring the effects of parasite loads, particularly leeches; understanding
population dynamics, reproduction, and predation; and understanding the effects
of people and other animals on turtle behavior.
By continuing to learn about turtles, conducting research, and
preserving habitat that is vital for turtle survival, we can help protect New Jersey’s turtle
species.
References:
Bonin, Franck, Bernard Devaux, and Alain Dupré. Turtles
of the World. Baltimore: Johns Hopkins UP, 2006. Print.
