Download reptile species identification

REPTILE SPECIES
IDENTIFICATION
# 8985-H
Table of Contents
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Introduction
Characteristics of Reptiles
Turtles
Crocodilians
Lizards
Snakes
Introduction
• Reptiles were the first true land vertebrates.
• Once the dominant land life form, reptiles
suffered several mass extinctions which
reduced their numbers.
• One possible reason for reptiles’ extinction was
impact from the Alvarez Asteroid.
• The impact could have thrown so much dust and
debris into the atmosphere that sunlight would
have been blocked and vegetation would have
died.
• Life either had to adapt or die.
• Reptiles, including dinosaurs, were among those
that faced extinction in large numbers.
Characteristics of Reptiles
• There are four principal groups of reptiles:
lizards, snakes, crocodilians, and turtles.
• Most reptiles have dry, scaly skin that resists
desiccation.
• Reptiles are not to be confused with
amphibians.
• Reptiles have a range of locomotion.
• The only limitation is that they cannot fly.
• Snakes move by curving their bodies from side to
side.
• Lizards walk on all four legs; some can walk on
their back two legs.
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Reptiles lay an amniotic egg.
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Fertilization takes place inside the body before the
eggs are laid.
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Fluids inside the egg surround the embryo.
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Reptiles were the first to use internal fertilization.
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Reptiles are poikilothermic. That is, their body
temperature will rise or fall with the temperature
of the environment.
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Reptiles still have to keep warm.
Thermoregulation is the activity of taking advantage
of the sun’s position to regulate body temperature.
Photo by Dennis Larson courtesy of USDA Natural Resource Conservation Service.
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Reptiles often hibernate to survive cold.
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During this time, they reduce body functions to
conserve energy.
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In pregnant females, embryo development will
stop.
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High temperatures and dry conditions can also
affect reptiles.
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Adapting to these conditions requires a period of
reduced activity called estivation.
• All reptiles have times when they are vulnerable to
predation.
• Reptiles have two types of outer coverings.
• One is a tough covering, as seen on crocodilians or
turtles.
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Snakes and lizards do not have this defense.
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Instead, they rely on speed and painful bites.
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Some species have venom, which can kill and deter
some predators.
Turtles
• Turtles are the group of reptiles with the
greatest economic benefit to humans,
primarily as a food source.
• Their protective shell
covering easily
identifies them.
Photo by John Mosesso courtesy of NBII
• Turtles do not have teeth.
• Instead, a sheath covering each jaw has sharp
cutting edges called tomium.
• Most turtles are herbivores, but some are
carnivores.
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Turtles are an intelligent species and can learn a
maze as fast as a rat.
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Females are fertilized internally.
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They lay eggs in the ground and then desert the
nests.
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Turtles have always been an aquatic species.
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Tortoises are fully land dwellers.
Below are the species of turtles that are discussed in
this presentation.
• Snapping turtle
• Stinkpot turtle
• Three-toed box turtle
• Texas map turtles
• Red-eared turtles
• Guadalupe spiny soft-shell turtle
• Texas tortoise
• Ridley sea turtle
Common Snapping Turtle
Chelydra serpentina serpentina
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The common snapping turtle is abundant and
widespread.
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It is a very aggressive turtle,
often attacking their aggressor.
IMS Photo
IMS Photo
Stinkpot Turtle
Sternotherus odoratus
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The stinkpot turtle gets its name due to a musky
secretion from two glands when the animal is
disturbed.
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They spend so much time
in the water that their
carapace is covered with
algae and water moss.
IMS Photo
Illustration by Karen Couch courtesy of U. S. Fish and Wildlife Service.
Three-toed Box Turtle
Terrapene carolina triunguis
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The three-toed box turtle is a dry-land turtle that
will close its shell when threatened.
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It usually lives in woodlands or thickets.
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This turtle species is most commonly used as a
pet.
IMS Photo
Texas Map Turtle
Graptemus versa
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Texas map turtles inhabit lakes and rivers and
are the smallest of the map turtles.
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They live exclusively in the Colorado River
system in Texas.
IMS Photo
Red-eared Turtle
Chrysemys scripta elegans
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The red-eared turtle is among the most common
turtles in Texas.
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It is easily identified by a broad, reddish stripe
behind the eye.
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It is a herbivore.
Photo by Lynn Betts courtesy of USDA Natural Resources Conservation Service.
Guadalupe Spiny Soft-shell Turtle
Trionyx spiniferus guadalupensis
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The Guadalupe spiny soft-shell turtle can run on
land with speed and agility.
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It has a soft, leathery shell and is free of scales.
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It is found in the counties that border the
Nueces, San Antonio, and Guadalupe Rivers.
IMS Photo
Texas Tortoise
Gopherus berlandieri
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The Texas tortoise is a land species that is most
active during early morning and late afternoon.
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It ranges from Del Rio, Texas to San Antonio,
Texas and southward.
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The prickly pear cactus is its main food.
IMS Photo
Ridley Sea Turtle
Lepidochelys kempi
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The Ridley sea turtle prefers tropical waters.
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Its limbs are modified into flippers.
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Ridley sea turtles nest on beaches near Corpus
Christi, Texas.
• Over-hunting and destruction of their eggs have
reduced the population and put the Ridley sea
turtle on the endangered species list.
• The Ridley is the smallest of the Atlantic sea
turtles.
IMS Photo
Photo by David Bowman courtesy of U. S. Fish and Wildlife Service.
Crocodilians
• The group, crocodilians, has the fewest
species, but has the largest of all living
reptiles.
• Only 21 species of alligators, caimans, and
crocodiles exist throughout the world.
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In addition to their teeth, these species have
extremely powerful tails, which are used when
swimming and as weapons.
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They run fast in a straight line, but cannot turn
fast when running.
• Females defend their nests very aggressively.
• Crocodilians are amphibious vertebrates, but lay
eggs on land.
• They have powerful jaws for closing down on prey,
but are so weak in opening their jaws that most
humans can easily hold the mouth shut.
American Alligator
Alligator mississippiensis
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The American alligator lives on land and in water.
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It prefers river swamps, lakes, and marshes.
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The American alligator ranges from Florida to all
along the southern
coastal plains,
including Texas.
Photo by Dick Bailey courtesy of U. S. Fish and Wildlife Service.
• Alligators are not as aggressive as crocodiles.
• The alligator has a broader snout when compared
to the crocodile.
• Generally, the alligator is black in color, but may
retain some light markings from its youth.
Photo by Ginger Corbin courtesy of U. S. Fish
and Wildlife Service.
Photo by Gary Stolz courtesy of U. S. Fish and Wildlife Service.
American Crocodile
Crocodylus acutus
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The American crocodile inhabits only brackish
water from Miami, Florida and southward.
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It is identified by its
long, tapering snout.
IMS Photo
Photo courtesy of U. S. Fish and Wildlife Service.
Spectacled Caiman
Caiman crocodilus
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The spectacled caiman is not a native to the
United States, but may occur locally due to the
pet trade and people releasing them.
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Its range is from Mexico to Argentina.
• A boney ridge in front of the eyes distinguish the
caiman from alligators and crocodiles.
Crocodile on left.
Caiman on right.
IMS Photo
• Caimens color may vary from greenish to
yellowish to brownish, and they have dark brown
crossbands.
Lizards
• Lizards were the last of the reptiles to evolve.
• Snakes and lizards make up 95 percent of all
known living reptiles.
• Lizards are extremely diverse.
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Species can live on land or burrow, while others
are aquatic and arboreal species.
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Some glide through the air.
• Most lizards eat insects, but some feed on plants
and some eat other lizards, small birds, and eggs.
• Only two species, the Gila monster (pictured at
right) and the beaded lizard in Mexico, have
venom.
IMS Photo
The following characteristics separate lizards from
snakes:
• Both halves of their lower jaw are united and they
cannot swallow oversized meals;
• They have moveable eyelids; and
• They have external ears.
• Like snakes, some lizards have a deeply forked
tongue that draws back into a sheath.
• If attacked and caught by the tail, some lizards can
drop off its tail to escape.
• The tail will re-grow, usually within seven weeks.
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A lack of skin glands and the way lizards produce
urine help conserve water and make a lizard
perfect for the hot, dry regions it inhabits.
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Some lizards store fat in their tails.
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This provides a reserve during drought.
Texas Banded Gecko
Coleonyx brevis
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The Texas banded gecko will feed on insects,
spiders, and other arthropods.
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They prefer habitat in rocky areas such as
canyons, but will establish themselves around
buildings and old docks in tropical seaports.
IMS Photo
Green Anole
Anolis carolinensis carolinensis
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The green anole is an abundant lizard in the
south and a common resident of central and
south Texas.
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This chameleon-like lizard can change color (from
green, to mottled green and brown, to brown) to
match its background.
IMS Photo
Collard Lizard
Crotaphytus collaris
• The collared lizard is easily identified by two black
collar markings.
• They are aggressive and cause a painful bite.
• Collard lizards live in rocky, arid regions.
Photo by Roger Karges courtesy of U. S. Fish
and Wildlife Service.
Photo courtesy of U. S. Fish and Wildlife Service.
Texas Earless Lizard
Holbrookia texana texana
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The Texas earless lizard has no visible ear
openings.
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It has black bars under the tail, which will curl
over the back.
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The Texas earless lizard is found in rocky
streambeds, limestone outcrops, or rocky areas.
IMS Photo
Crevice Spiny Lizard
Sceloporus poinsetti poinsetti
• The crevice spiny lizard has a rough, almost pine
cone appearance.
• It is common to the Edwards Plateau of Texas
where they reside among boulders and rocky
outcrops.
IMS Photo
Desert Side-blotched Lizard
Uta stansburiana stejnegeri
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The desert side-botched lizard is a blue-flecked
lizard with a black spot behind the armpit.
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It is found in sandy regions and on desert flats and
foothills in the western half of Texas.
IMS Photo
Texas Horned Lizard
Phrynosoma cornutum
• The Texas horned lizard is commonly called the
“horny toad.”
• Two central head spikes are much larger than
others.
• These lizards will squirt blood from the corners of
their eyes up to several feet as a defense.
The Texas horned lizard is a protected species in Texas
and should not be collected.
Photo by Gary Stolz courtesy of the U. S. Fish and Wildlife Service.
Six-lined Racerunner
Cnemidophorus sexlineatus sexlineatus
• The six-lined racerunner is found in the eastern
part of Texas.
• It has six light stripes down its back.
• The six-lined racerunner is very difficult to catch.
Great Plains Skink
Eumeces obsoletus
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The Great Plains skink is a smooth, shiny, alert,
and active lizard.
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It feeds mainly on baby mice, baby birds, and
bird eggs.
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It is the largest of all skinks in the eastern and
central parts of the U.S.
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It is found along watercourses.
They have strong jaws and can inflict a painful bite.
Photo by Gary Stolz courtesy of the U. S. Fish and Wildlife Service.
Slender Glass Lizard
Ophisaurus attenuatus
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The slender glass lizard is often mistaken for a
snake.
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It is found in dry grasslands or open, dry woods.
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They resist capture.
IMS Photo
Snakes
• Snakes are the main reptile land predator and
are almost as widespread as lizards.
• They have only one lung, many vertebrae, and
they lack limbs.
• Snakes swallow their food whole. Teeth slanted
backward aid in this process.
• The bones of the skull are loosely connected,
which also aids in swallowing prey.
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Most snakes have poor vision and poor hearing.
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They are sensitive to sounds carried through the
ground.
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Snakes seek prey using Jacobson’s organs located
in the roof of their mouth.
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Working with the tongue, these organs pick up
scent particles of prey.
Snakes will travel either by side- winding, rectilinear,
or concertina movement.
• Snakes reproduce by one of three methods.
• Some are oviparous, which means they lay eggs.
• Some are ovoviviparous, which means the embryo
develops inside the female body in an egg casing
with minimum nourishment coming from the
female.
• Still others are viviparous, which means the female
provides nourishment to the embryos through the
placenta.
• Snakes do not care for their young after birth.
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The majority of snakes in the world are nonpoisonous.
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Still, their saliva has limited toxic qualities to aid
digestion and bites from non-poisonous snakes
should be treated immediately.
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Poisonous species produce venom.
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The venom is used to kill prey or an attacker.
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Only four groups of snakes in North America are
poisonous.
Non-poisonous Snake Species
Below are the non-poisonous snakes discussed in this
presentation.
• Plains blind snake
• Western coachwhip
• Diamondback water snake • Great Plains rat snake
• Ribbon snake
• Bullsnake
• Rough green snake
• Speckled kingsnake
• Hognose snake
• Louisiana milk snake
• Prairie ringneck snake
Plains Blind Snake
Leptotyphlops dulcis dulcis
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The Plains blind snake is a subspecies of the Texas
blind snake.
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It is a worm-like species with vestigial eyes and
lives underground in the Plains and other dry
regions.
IMS Photo
Diamondback Water Snake
Natrix rhombifera rhombifera
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The diamondback water snake is a harmless, semiaquatic species found near water.
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They feed on frogs, salamanders, fish, and
crayfish.
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The diamondback water snake will strike and bite
hard when cornered.
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It is often confused with the cottonmouth.
IMS Photo
Western Ribbon Snake
Thamnophis proximus proximus
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The ribbon snakes are members of the garter
snake group.
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They are the thinnest, trimmest members of that
group.
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The western ribbon snake prefers being close to
water.
IMS Photo
Rough Green Snake
Opheodrys aestivus
• The rough green snake prefers habitat of leafy
trees and shrubs, where it can feed mainly on
insects.
• It preys on caterpillars, spiders, grasshoppers,
crickets, dragonflies, and mayflies.
• Rough green snakes rarely bite humans.
IMS Photo
Eastern Hognose Snake
Heterodon platyrhinos
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The hognose snake has a sharply upturned snout
with a keel on top.
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If attacked, it will flatten its head and neck, hiss
loudly, and inflate its body with air.
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If this fails, it will roll on its back, open its mouth,
convulse, and play dead.
IMS Photo
Prairie Ringneck Snake
Diadophis punctatus arnyi
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The prairie ringneck snake prefers rocky hillsides
in open woods in central and south Texas.
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The prairie ringneck will tightly coil and elevate its
tail to show the yellow and red colors of its
underside.
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It has a dark head.
IMS Photo
Western Coachwhip
masticophis flagellum testaceus
• The western coachwhip can vibrate its tail,
sometimes sounding like a rattlesnake.
• It prefers grasslands, mesquite savannas, arid
brushlands, and other open habitats.
• It is a common Texas snake.
IMS Photo
Great Plains Rat Snake
Elaphe guttata emoryi
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Great Plains rat snakes are found in canyons or
rocky draws.
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They are secretive and essentially nocturnal.
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They are good climbers and if cornered, will
actually stand up and fight with the fore portion
of their body reared upward.
IMS Photo
Bullsnake
Pituophis melanoleucus sayi
The bullsnake is at home on plains
and prairies.
Bullsnakes are aggressive and can
kill rattlesnakes.
Photo courtesy of U. S. Fish and Wildlife Service.
Speckled Kingsnake
Lampropeltis getulus holbrooke
• The speckled kingsnake is a powerful constrictor.
• It will kill and eat other snakes, including venomous
ones.
• It has dark scales with white or yellowish spots.
IMS Photo
Louisiana Milk Snake
Lampropeltis triangulum amaura
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The Louisiana milk snake is a black, red, and
yellow striped species that resembles the
poisonous coral snake.
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The difference in the two are in this safe warning:
“Red touch black, friend of Jack (or, venom lack),
red touch yellow, kill a fellow.”
The Louisiana milk snake is harmless, yet it can be
aggressive.
IMS Photo
Poisonous Snakes
• Poisonous snakes are divided into three categories
based on the type of fang.
• Vipers have tubular fangs at the front of the mouth
(Ex. rattlesnakes).
• Elapids have short, permanent erect fangs and
venom is injected when chewing (Ex. coral snakes).
• Colubrids have a few rear-fanged venoumous
species of African origin, such as the Boomslang
and Twig Snake, but most colubrids are not a
danger to humans.
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There are two classes of venom, neurotoxin and
hemolytic.
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Neurotoxins attack the nervous system.
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Hemolytic venom breaks down red blood cells
and blood vessels.
The four species of poisonous snakes found in Texas
are listed below.
• Texas coral snake
• Southern copperhead
• Western cottonmouth
• Rattlesnakes
Texas Coral Snake
Micrurus fulvius tenere
• The Texas coral snake has neurotoxic venom and is
dangerously poisonous.
• It is identified by red, yellow, and black rings.
• Its snout is black and on this species, the red band
will touch the yellow band (“red touch yellow, kill
a fellow”).
IMS Photo
Photo by Luther Goldman courtesy of U. S. Fish and Wildlife Service.
Southern Copperhead
Agkistrodon contortrix contortrix
The southern copperhead has
hemolytic-type venom.
They blend well
into autumn leaves
on the ground.
A copperhead
has a coppery-red head and a narrow
hourglass pattern on its back.
Photo courtesy of U. S. Fish and Wildlife Service.
IMS Photo
Western Cottonmouth
Agkistrodon piscivorus leucostoma
• The western cottonmouth also has hemolytic-type
venom.
• It will usually stand its ground and, when aroused, it
will vibrate its tail, throw its head back, and open its
mouth revealing the white interior.
• The white mouth gives it the name cottonmouth.
Photo by Matthew Perry courtesy of U. S. Fish & Wildlife Service.
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Cottonmouths are common to swamps and
bayous.
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Cottonmouths are olive, brown, or black on their
dorsal sides.
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Many have no trace of a pattern, while some have
dark crossbands.
IMS Photo
Rattlesnakes
• Rattlesnakes are so-named by the the loosely
attached, horny tail segments that rattle when the
tail vibrates.
• The western diamondback rattlesnake (Crotalus
atrox) is named for the diamond-like pattern
extending the length of its back.
• The western diamondback rattlesnake is generally
brown or gray in color, but may have reddish or
yellowish tones.
• It also has a ringed tail of black and white or light
gray.
Photo by Luther Goldman courtesy of U. S. Fish and Wildlife Service.
Photo by Gary Stolz courtesy of U. S. Fish and Wildlife Service.
The cottonmouth and
rattlesnakes are very
dangerous snakes.
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Reproduction or redistribution of all, or part, of this
presentation without written permission is prohibited.
Instructional Materials Service
Texas A&M University
2588 TAMUS
College Station, Texas 77843-2588
http://www-ims.tamu.edu
2006