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The Bite of The Caiman

Objectives of the Lesson
Background Information
Materials Needed
Procedure
Evaluation/Alternative Assessment
Web Resources


Objectives of the Lesson:

Students will:

  1. Create/construct a model of the bite of the caiman in a class activity.
  2. Calculate the length of the caiman from the size of the model bite.
  3. Take the model home, show it to classmates, and be able to present information on caimans from Manu from this activity.

Background Information:

Caimans are very large reptiles. They survive in Manu because it is a national park and they are protected. The pet trade has had a disastrous effect on caimans as well as the skin trade. Caimans have a terrible bite. The bite is more like a crocodile than an alligator. The Black Caiman and Smooth Front Caiman are the largest species. The teeth are long and sharp and are arranged in a symmetrical shape on the jaw. It appears otherwise due to the battles it encounters while hunting. Caiman teeth protrude from both the upper and lower jaw.

Small caimans are victims of the pet trade but this is decreasing due to the availability of captive raised reptiles. The larger caimans are victims of the leather trade taken from the wild.

Juvenile caimans have a ratio of jaw length to overall length of 6 to 1 and adult specimens have a ratio of jaw length to overall length of 8 or 9 to 1. Please remember that these figures are approximate. (Interview, Harry Ward, Associate Curator of Reptiles, Detroit Zoological Park, Royal Oak, Michigan, October 17, 1997.)

Materials Needed:

  • A copy of the PBS program, The Living Edens: "Manu, Peru's Hidden Rain Forest" (Air date November 12, 1997 on PBS. If you miss this program, you can order the video.)
  • One piece of wood, approximately 9 x 12 inches and 3/4 - 1 inch thick (Scrap wood can be found in the woodshop of school or possibly the art teacher)
  • One hammer and one large nail (approximately 3-4 inches long) for each group of 4 students
  • Downloaded template for the bite of a small caiman (could be enlarged for larger specimens): Template
  • Black marker for highlighting tooth marks for each group of four students
  • Ball-point pen for each group of four students
  • Safety Glasses for each student
  • Sandpaper for each group of four students
  • Thumbtacks

Procedure:

  1. View The Living Edens: "Manu, Peru's Hidden Rain Forest" program in class. Note the sections on caimans.
  2. Download Caiman Bite Template here: template. Enlarge if desired and give one copy to each student. Different sizes will give different lengths of the caiman.
  3. Have students attach the template to the piece of wood using thumbtacks. Use ball-point pen to write name on piece of wood. Students may also name the caiman.
  4. Have students pound the nail into the wood about 1/2 inch deep and outline the nail hole with a black marker. Students may wiggle the nail in the hole to enlarge those teeth in the front of the jaw. This is more realistic.

Evaluation/Alternative Assessment:

Review the finished product and share calculations on the size of the caiman using the formula of 6 to 1. I suggest this ratio as the size of the bite on the template is that of a juvenile caiman. Whatever the bite size, the length is approximately six times the bite size. If the bite size is 8 inches long, the length of the caiman is approximately 48 inches long.

Discuss with students what caimans are, what they eat, and why they are still found in Manu. This information is presented in the film.

Elementary Extension:

It would be a great activity to construct a life size caiman out of paper mache. This could then be painted and used for inspiration in writing a story about Manu and the life of the caiman.

Secondary Extension:

Investigate the different species of caimans and/or crocodiles found in tropical areas of the world. You could also pursue researching caiman populations worldwide and investigate the problems facing this reptile.

Web Resources:

http://cord.iupui.edu/~tethais/learn.html

http://www.bio.bris.ac.uk/research/crocs/csp_mnig.htm

http://hammock.ifas.ufl.edu/txt/fairs/43552/

http://www.pathfinder.com/@@cSpiPAUAmialfvPO/PetPath/Exotic/Breeds/REPTAM/CAIMAN/CAIMAN.html

http://www.jaglair.com/rain/rfcai.htm

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