Unlike mammals (warm-blooded) that have a mechanism to keep the body’s internal temperature consistent, reptiles are ecto-therms (cold-blooded) which means they depend on the surrounding temperatures for their metabolism. A temperature range of 75-95 degrees cannot be accomplished with an inadequately sized enclosure. A basking light is used to raise the iguanas’ internal temperatures. This light provides a localized, higher temperature that will activate its micro flora. This beneficial bacteria needs to be at 85 degrees to become active enough to break down the cellulose in plants. It’s in the hindgut where 30-40% of the plants nutrients are extracted. That’s a lot of nutrition that would otherwise be missed. This so called “hot-spot” can be as high as 95-100 degrees. If the iguana doesn’t have enough room to move in and out of the thermo gradiant, it will be subject to thermal burns. One source of heat that is not recommended is the hot rock. Iguanas are heliotherms, which means they get their source of heat from above, as in the sun. An iguanas heat sensor is located in its head at the base of the brain. They don’t have the kind of heat sensors in their skin that we do. An iguana basking on a tree branch is not going to get burned from an overheated branch. When the iguana gets too warm, it moves out of the sunlight into the shadow of the leaves to cool off. Its blood has warmed up to the point where it tells the heat sensor in the head to move. However, if the iguana is sitting on a hot rock, by the time the blood is warm enough, the skin has burned.
Depending on the type of habitat, acceptable heat sources are space heaters for a free roaming, or room type enclosure, or ceramic heat emitters. These are heat elements encased in ceramic that can be screwed into a light fixture. All heat sources need to be positioned in a safe area where the iguana can’t knock it over or attempt to lay on it. Ceramic heat emitters, or che, can be used as a nighttime heat source. It produces heat, but no light. They range in price from $30-$50 but usually last up to five years.
Another heat source is the combination heat/UVB light. These mercury vapor lights screw into light fixtures and look like a huge light bulb. In addition to heat they also provide some amount of
UVB light. They do produce a lot of heat and are suitable only for large enclosures.
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