The
Common Snapping Turtle
by
Mike Roberts, Contributing Columnist
The Common Snapping Turtle (Chelydra
serpentina)
Appropriately named for its defensive
tactics, the common snapping turtle has long been maligned by well-meaning
humans, mainly because of unfounded fear and generations of folklore.
Revealing this semi-aquatic reptile�s seasonal behavior is unlikely to
reverse such mindsets, but for the sake of understanding, let�s try!
As a kid who loved to fish, I distinctly
remember two things my grandfather told me about snapping turtles. First, if
one latches onto your finger, the animal will not release its vise-like grip
until thunder sounds. That threat was enough to make me keep my hands well
out of striking distance of the occasional ill-tempered turtle
that inhaled a minnow or worm intended for bass and bluegills.
The other information my grandfather
offered about snapping turtles was that they were good to eat. He declared
they had seven flavors of meat in their bodies � one of which even tasted
like chicken and was best prepared as a soup dish. Growing up on a farm,
however, I saw no need to chance pain because of some reptile�s nasty
disposition about becoming table fare, especially with all the chickens
running around our barnyard.
Then one warm, spring evening, upon
angrily examining a stringer of mangled, largemouth-bass carcasses, I began
blaming snapping turtles for the disappearance of
wildlife from the neighborhood ponds � especially fish and ducklings. As a
kid, I failed to consider that foxes, raccoons, minks, river otters, water
snakes, great blue herons, red-tailed hawks, great horned owls and ospreys
were taking their fair share, too. Even as a budding naturalist, it took me
half a lifetime to develop a personal appreciation for the snapping
turtle�s seemingly sinister role in helping to balance the natural
environment.
Perhaps the most notable part of the
common snapping turtle�s morphology, like all 260 or so species of turtles
around the world, is the shell. This hard, outer covering is divided into
two distinctive parts � the upper section, called the carapace, and the
lower section, called the plastron. In most species, both sections are fused
together, but those of the snapping turtle are held together by ligaments.
The animal�s vertebrae and ribs are fused with the carapace, which is
comprised of bones covered with unique plates, called scutes. These
epidermal plates are shed and replaced as the animal grows. The majority of
turtles can retract their head, neck, legs and tail within the safety of the
shell, but snapping turtles cannot. Ironically, they have the smallest
plastron of any species.
With the exception of humans, snapping
turtles have few predators. When on land, any vulnerability is offset by
maintaining a head-on, defensive posture, lightning-quick head lunges, loud
hissing, and repeated attempts to bite the assailant with its sharp, hooked,
keratinous beak. Such behavior has served to label them with the reputation
of being fierce and aggressive creatures. Still, when in water (where they
spend the majority of their lives), snapping turtles flee at the first sight
of humans.
Like all reptiles, snapping turtles are
ectothermic in nature. In other words, as a cold-blooded animal, they must
control their internal temperature by sources outside the body. Seldom do
they crawl out of water onto logs or rocks to bask � the manner of
thermoregulation preferred by many turtle species. When basking, snapping
turtles either lie motionless in shallow water or swim to the surface of
deeper water and, while floating, expose the entire top surface of the
carapace. Basking raises the turtle�s internal body temperature, which
aids in food digestion. Direct sunlight also helps to reduce the growth of
algae on the shell, and some biologists believe it necessary to prevent
shell diseases.
During spring, the male snapping turtles
(distinguished by longer tails and larger bodies), move from pond to pond
searching out receptive females. Sometimes exceeding 40 pounds, the warriors
battle over territorial and breeding rights, which creates quite a
spectacle. Locked in each other�s muscular, four-legged grip, the
combatants roll about in the water and mud for hours, all the while trying
to kick, scratch and bite their way to an eventual snapping turtle
honeymoon.
With the warming temperatures of late
May and June, the pregnant females leave the security of the ponds and
slow-moving streams to seek out suitable nesting sites. These sites vary
from open fields to pond dams, roadways and dirt banks and usually are
located away from water. Once an area has been selected, the expectant
mother digs several holes, but deposits the spherical white eggs (typically
20 or more) in only one of the cavities. This curious behavior is likely to
confuse predators that relish fresh turtle eggs. After sealing the cavity
opening with soil, the female heads back to the water. Marauding skunks and
raccoons consume the majority of the eggs within a day or two of having been
laid. Still, in compliance with the laws of nature, a percentage of the eggs
survives predation to assure continuation of the species.
Like some other reptiles, particularly
alligators and crocodiles, incubation temperature dictates the sex of the
snapping turtle hatchlings. Yet, because of all the variables associated
with the annual
egg-laying process and the depth of the
nest cavity, each nest is likely to produce both males and females within
approximately three months of incubation by the warmth of the summer sun.
Snapping turtles feed during the day and
at nighttime on a diet of both aquatic vegetation and animal material. As
scavengers, they locate dead fish and other animals in the water by
utilizing the combined senses of sight and smell. Being opportunistic
predators, these turtles are capable of catching small vertebrates that
share the same habitat � including fish and ducklings. The life expectancy
of snapping turtles can exceed 50 years. In the northern latitudes of their
range, they spend the winter months submerged and buried in mud, whereas
further south they remain active throughout the year.
Although not nearly as impressive as the
legendary alligator snapper that resides in the swamps of the
Deep South
, the common snapping turtle has adapted to increased human populations,
which is understandable; the species has survived environmental change for
millions of years, perhaps even watching the coming and going of dinosaurs.
Soup, anyone?
Wild Bird Profile: Red-winged Blackbird
Agelaius phoeniceus
After a full winter�s absence of
birdsong, a favorite anticipation of birdwatchers is the spirit-lifting,
migratory homecoming of male red-winged blackbirds to the lifeless reeds and
cattail stalks of their springtime habitat.
More often than not, however, frigid
temperatures and snowflakes greet these flocks of returning travelers.
Still, with increasing daylight hours and eventual warming temperatures, the
birds begin staking out individual territories, flaring scarlet epaulets,
and filling the air with their coarse, gurgling songs of �konk-la-ree,
konk-la-reee.� Upon the delayed arrival of the females (easily
distinguished by dark-brown, topside attire, and heavily streaked, tan
breast feathers), the �pomp and ceremony� of the male�s breeding
activity greatly intensifies.
True to their family�s Latin namesake,
troupial (TROOP-ih-al), meaning the habit of gathering in large flocks,
red-winged blackbirds are one of the most abundant songbirds in
North America
. Often mixing with grackles and numbering in the millions, these migrating
masses of birdlife occasionally confuse meteorologists by showing up as
clouds moving across the radar screen.
As further evidence of subtle
environmental changes occurring across our planet, the blackbird, that
historically nested in the shrubs and tall vegetation of open marshes and
along the edges of ponds, now also selects nest sites far from water, even
in open hayfields. Nesting usually begins in April. The female incubates her
four blue eggs for approximately 12 days. Occasionally polygamous, the male
red-winged blackbird aggressively defends the eggs and young from predators,
especially crows and hawks that venture into private airspace.