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Wild about Reptiles (GMHDRNC)

TopicLaboratory and Hands-on Activities - General
Outdoor Skills - Identification
Wildlife - Reptiles
Summary
This hands-on program studies the similarities and differences among alligators, lizards, snakes and turtles. Find out what they eat, where they live and why they are so important.
Grade LevelK - 12
Recommended SettingIndoor or outdoor classroom
LocationGovernor Mike Huckabee Delta Rivers Nature Center, Pine Bluff
Contact
Education Program Coordinator, 870-534-0011
Duration45 minutes - 1 hour
Suggested Number of Participants10 - 30
Objectives
  • Understand the physical and behavioral characteristics of reptiles.
  • Learn the similarities and differences among this group and other groups of animals.
  • Learn the similarities and differences of species within the class Reptilia.
  • Understand the importance of reptiles and their habitat.
Key Terms*

Cold-blooded

Jacobson’s organ

Omnivorous

Osteoderm

Scale

Scute

Venomous

Materials

Live turtles, lizards and/or a juvenile alligator

Background

Snakes, lizards, turtles and alligators belong to the class Reptilia. There are about 6,000 species of reptiles worldwide and around 140 in Arkansas. Reptiles are cold-blooded, scale-covered, (mostly) egg-laying animals that spend most of their lives on land. They are a misunderstood group, often killed due to fear rather than reason. In actuality, they are interesting and helpful, especially in controlling pests.

Procedure
  1. Prior to the presentation, decide which kinds of live animals to show and arrange the discussion accordingly.
  2. Turtles are the oldest reptiles on Earth. Discuss the three kinds of turtles: soft-shelled water turtles, hard-shelled water turtles and hard-shelled land turtles. Remind participants about basic turtle information.
    • The shells have scales that protect their soft skin underneath. In hard-shelled turtles, the shells are composed of scales that have hardened, called scutes. These scutes fuse to form the shell.
    • Another interesting physical characteristic of turtles is that they have no teeth but rely on a bony beak to snap off their food, anything from vegetation to small fish.
  3. There are more than 3,000 kinds of lizards in the world. In Arkansas, there are only 13. Explain some of the unique characteristics.
    • Some lizards can climb walls. Using the rough surfaces of their feet, these creatures can hook onto the microscopic edges of surfaces as smooth as glass.
    • Another unique feature is their tail. If in danger, lizards can detach their tails to distract the predator. Later, they grow another one. The second one is made of cartilage and never quite looks the same, but it is a small price to pay to stay alive.
  4. There are 36 kinds of snakes in Arkansas, but only six are venomous. Discuss snake biology and poisonous and nonpoisonous snakes.
    • Snakes don’t have ears; they use their bodies to feel vibrations of approaching animals. Since they don’t see well, snakes rely on their sense of smell by using their tongues. When a snake flicks its tongue, it actually smells. By touching the forked ends to openings in the top of their mouths, they can determine what sorts of prey are near and information about their surroundings. These holes are called the Jacobson’s organ.
    • Of all the different kinds of snakes in the world, only about 10 percent are venomous. Of the six dangerous snakes in Arkansas, none are poisonous. Poison must be ingested, but venom must be injected. Venom works within the bloodstream while poison works in the digestive system.
    • There are three fairly easy ways to distinguish venomous from nonvenomous snakes. First, the shape of the head is an easy sign. Snakes whose heads are diamond-shaped are venomous, and those with thumb-shaped heads are generally nonvenomous. A second sign is the shape of the pupil. Nonvenomous snakes have circular pupils, while venomous snakes have slitted pupils, like cat’s eyes. One important exception to these rules is the Texas coral snake. Though highly venomous, it has both circular pupils and a thumb-shaped head. The third way to distinguish between venomous and nonvenomous snakes is the scale pattern on the underside of the tail. Nonvenomous snakes have divided scales, and the scales on venomous snakes appear banded.
  5. Found in about 45 of Arkansas’s 75 counties, the alligator is North America’s largest reptile, growing up to 18 feet. Talk about the eating habits and/or reproductive cycle of the animal.
    • They have rough scales, lay eggs and are poikilothermic, a scientific term for cold-blooded meaning their internal temperatures vary depending on the outside temperature. Alligators are opportunistic carnivores and will eat almost any meat they can swallow. However, they can only digest food when their body temperature is above 80 degrees Fahrenheit. Because of this, alligators don’t usually eat between November and March. Since they only have teeth for ripping and tearing and none for grinding, they have to either swallow their food whole or tear small hunks of larger prey.
    • Alligators, like other reptiles, lay eggs in nests. The sex of the babies (about six inches at birth) depends on the temperature of the nest of decomposing vegetation. As they grow, the scales along their backs harden to bone. These bony ridges are a form of osteoderm called scutes that protect the animal from predators.
  6. Present the educational animal. This can be done throughout the discussion as a visual aid. If the group is small enough or if there is enough time, allow participants to touch the animals. Stress the importance of hygiene and have participants clean their hands after contact.
  7. Answer any questions.
Review
  • What features classify an animal as a reptile?
  • Are snakes poisonous? Why or why not?
  • What contributions do snakes make to the their ecosystems?
  • How do alligators ingest their food?
Related Documents
Glossary

Cold-blooded – (ectothermic) – relating to an organism that regulates its body temperature by exchanging heat with its surroundings

 

Jacobson’s Organ – either of a pair of blind, tubular, olfactory sacs in the roof of the mouth, no longer functional in humans but well-developed in many animals, especially reptiles

 

Omnivorous – eating both animal and plant foods indiscriminately

 

Osteoderm – bony deposits forming scales, plates or other structures in the skin, often serving as defensive armor

 

Scale – one of the thin, flat, horny plates that cover certain animals such as snakes, lizards and pangolins; or one of the hard, bony plates covering certain other animals such as fishes

 

Scute – a bony external plate similar to scales but derived from the epidermis; describes the scales of some armored mammals, such as the armadillo, and occasionally used as an alternative to scales in describing certain fishes, such as sturgeons

 

Venomous – able to inflict a poisoned bite, sting or wound