Heating and Light
Hatchling iguanas are especially vulnerable to chill, so maintaining
a high enough cage temperature is critical to their successful growth
and survival. Establishing an appropriate temperature range is
important because it allows the animal to thermoregulate, or control
its own body temperature, by moving to the areas with optimal or
comfortable temperatures.
For young iguanas, an optimal temperature range is about 75 to 80° F
(23 to 27° C) in the coolest part of the habitat (and as a minimum
night temperature) to 90 to 100° F (32 to 38° C) under a
basking light. Adult iguanas can tolerate much cooler night temperatures
(down to 65° F) as long as they can become warm enough during the
day. One strategy to provide both adequate base heat and a good
gradient is to heat the cage bottom to about 75 to 80° F with
either a high-quality hot rock or an under-tank heater (which is
similar to a heating pad).
Basking heat may be provided with an incandescent light placed above
the screen, as iguanas bask in sunlight in nature. Place a branch or
shelf directly under the light so the lizard may quickly raise its
body temperature to as high as 90 to 100° F when directly under
the light source. Do not let the lizard come into direct contact with
the bulb, as severe burns may result. The lights should be turned off
after 12 to 14 hours to allow the iguana to have a normal day/night
cycle. A timer can ensure consistency of the photoperiod.
Classroom Activities
As your students become familiar with the biology and habits of the
classroom iguana, they will come up with hypotheses to explain what
they see and to explore "what if?" questions. Take full advantage of
their fascination with the lizard and encourage them to design
observational experiments to learn more about iguanas, their biology,
and the scientific method. Here are some ideas to get you started.
- How does the iguana react to its image in a mirror? Do its reactions
change as it gets older? What kind of body language does the iguana use,
and what does it mean? What is the sex of your iguana?
- Use food coloring to dye the same type of food (such as iceberg
lettuce). Do iguanas have distinct color preferences as measured by
the amount of foods of different colors ingested? How could the
experiment be designed to eliminate bias and error?
- Younger children can discuss what makes an iguana a reptile, rather
than a bird, amphibian, or mammal, and draw the differences. Compare
iguanas with dinosaurs.
|
Have students inspect the feces of your iguana under a microscope.
Can you identify the bacteria and protozoans that aid in digestion of
plant materials? Hindgut fermenters such as iguanas digest food more
effectively at higher temperatures. How could you find out why this is
so?
Observe the behavior of the iguana throughout the day. Where in the
cage (vertically and laterally) does it go at particular times of the
day? What is the temperature? Is the iguana active or passive? Does
its color or orientation change? Why might the color or orientation
of its body (in relation to a heat or light source) change over the
time of day? Make observations over days or weeks to identify patterns.
Chart the growth of the iguana over time, relating its length and
mass. Save the previous year's data for a continuous record. Keep
track of how much the iguana eats (quality and quantity), and discuss
food conversion, the food chain, and efficiency in farming. Why would
the rapid growth of iguanas on a vegetarian diet cause it to be such
a good candidate for tropical agriculture? How does iguana farming in
the tropics compare, in terms of efficiency of food conversion and
environmental effects, with raising cattle for profit?
Conclusion
Before making the decision to purchase an iguana, carefully consider
its dietary, temperature, and space needs. Research the requirements
of the animal, and be aware of the commitment involved in keeping one
of these long-lived lizards for the duration of its life. Iguanas are
fascinating and magnificent lizards. Potentially more docile and
personable than many reptile species commonly kept in captivity,
iguanas may be among the most interactive and responsive classroom
animals. With proper care and attention, they make spectacular
classroom subjects.
Further Reading
Mattison, C. 1991. Keeping and Breeding Lizards. Blandford
Publishers, London.
Ramus, E., and J. Gillmore. 1995. Reptiles in the classroom. Reptile
& amphibian Magazine (Nov/Dec): 72-81.
Samuelson, P. 1995. The Lizard king. Reptiles Magazine 3: 64-83.
Vosjoli, Philippe. 1992. The Green Iguana Manual. Advanced
Vivarium Systems, Lakeside, CA.
|
