Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014


Change-related stress in green iguanas and other reptiles

©2000 Melissa Kaplan


Iguanas and other reptiles always have a reason for doing what they do. Figuring out just what that reason is will be your challenge. While the following article was written and refers to articles relating to green iguanas, the information is applicable to other iguanids, to many agamids and other types of reptiles.

Change is particularly difficult for iguanas, especially those who have been used to the same daily routine for a long time. As discussed in my Iguana Care, Feeding and Socialization article, the more quickly you establish a daily routine, the faster your new iguana will settle down and start to relax. But life is nothing if not change, and so some change will be inevitable. Understanding the types of things that will can cause iguanas stress will help you figure out what may be going on and, if not actually able to do something to make him feel better right away, understand that in some cases he will indeed adjust as time goes on and you can both get back to feeling okay again.


What is stress?
There are essentially three types of stress:

Environmental stress relates to problems with the lighting, heating, photoperiods, space, and furnishings.

Behavioral stress relates to alterations in the iguana's daily routine which lead to unhealthy behavioral changes.

Social stress relates to stresses in the social structure, which includes the humans as well as any other iguanas with whom the iguana interacts.

Signs of stress can manifest in one or more changes in:

  • Appetite - decreased or increased (not related to normal shedding)
  • Attitude - aggressive, lethargic, cranky, clingy, mopey (not related to normal shedding)
  • Daily routine - altered basking, sleeping, soaking, lounging, choosing cold places to stay for prolonged periods or until forcibly moved (not related to normal shedding)
  • Digging, snout-banging, escape attempts
  • Feces and urates - consistency, color, frequency (not related to normal shedding)
  • Interaction with keeper or others - increased, decreased, altered (not related to normal shedding)
  • Potty habits - breaking potty training, poop painting, retributive pooping
  • Shedding problems
  • Skin color - darkening (not related to normal shedding)
  • Other signs such as pale mouth tissues, dehydration, increase in internal parasites, appearance of abscesses, hiding

Additional information on these types of changes and what to do about them can be found in my Signs of Illness & Stress, Housing Multiple Iguanas, Iguana Skin Color, Reptile Skin Shedding, and Moving and Vacation Stress articles.


So, how do you know what's causing the stress reaction?
Unfortunately, an iguana doesn't hold up a sign or otherwise indicate which of the three types of stress is stressing him out at the moment, leaving you to figure out what is causing the stress and what if anything you can do about it. To do so, you will need to evaluate the overall situation, not only the behavior or incident but the events surrounding it. Iguanas are amazingly sensitive to their humans and will react with abnormal behaviors when their humans are out of sorts or dealing with unusual stresses. Try to look at things through your iguana's eyes, through the eyes of a wild animal living in a strange place. Things that can cause change-related stress include:

Altering his physical environment
Changing anything in his enclosure; changing anything in that part of the room he can see from his enclosure; moving his enclosure to a different place or different room; moving him to a new enclosure.

Altering his daily routine
Changing the timing of when you do things; changing your daily schedule, such as when you take vacation days at home instead of going to work (or summer vs. regular school schedules for students); being away from home for prolonged periods when you are normally at home during the day; significant alterations in your daily work schedule; wedding planning and the other general craziness leading up to a wedding or other big family event; business trips.

Household changes
Moving to a new home; remodeling; redecorating; rearranging furniture; putting up holiday decorations; specific holiday decorations; other pets added or subtracted from the household; family members or roommates added or subtracted from the household; guests coming to stay for several days or longer.

When iguanas are stressed, or entering a shed period, or just decides that they don't like their usual basking areas, they will usually seek out someplace cold, dark and usually tight-fitting in which to spend the day. While this doesn't seem like very smart behavior, it is their way of escaping from their reality for a bit. An otherwise healthy iguana can be allowed to remain in such a place for a day or two, but eventually, the reason for the behavior must be determined and dealt with.

In cases of stress, the source will have to be identified and resolved, with some quality time spent with the iguana to help ease him through it. In the case of being tired of the basking area already set up, it may be a seasonal thing, with the iguana actually seeking a brighter source during winter, or a more interesting view. Or, it could have outgrown the old basking spot, or something in the area around the spot has changed, making it less comfortable or secure for the iguana


Taming: Not Just To Make Life Easier For The Keeper
The difference between untamed and socialized is the reaction to their keeper. The reaction of an untamed or barely tamed iguana to keeper contact is going to be "RUN! It's a human!" A well socialized iguana, on the other hand, is unlikely to do more than cock an eye at its keeper, as if to say "Oh, it's you again, huh? Yawn." A tame but unsocialized iguana will come to an alert state but won't thrash around. Much.

Untamed iguanas are more stressed than tamed ones as they never attain the level of comfort with even the most basic daily keeper activities, including cage cleaning, feeding, claw trimming, etc. Behavior modification designed to reduce stress is commonly done in zoos to reduce the stress reactions and improve animal and keeper safety when conducting daily maintenance activities. Wild animals kept in captivity need the same type of taming for the same reasons.


A Bored Iguana Is An Imaginative Iguana
If you are away at work or school for regular periods of time, five days a week, week after week, your iguana gets used to your schedule and to your being gone. This regular cycle of your being home and gone, home and gone, becomes part of his daily routine. Your iguana may even be used to your having a social life outside of your house, adapting to these relatively short periods of time you spend away from home during the week and on weekends. This means that longer absences, ones not punctuating by your presence at home, will be noticed. When this happens, it will cause him stress, often severe stress.

Stress can lead to various behaviors, including trashing the food and water you left for him and redecorating the enclosure. Redecorating may just mean ripping up the substrate and pulling down his climbers. It can also mean pulling down light fixtures. Since light bulbs are made of glass, this often results in shards of glass all over the enclosure. Other times, the heat fixture may be twisted, or falls just the right way, resulting in the heat source being close enough to a flammable material to start a fire. Not a few homes and school buildings have been destroyed by fire from iguana heat lamps when their humans were absent.

A bored iguana may also try to dig his way out of his enclosure, spending hours scrabbling and clawing at the floor or walls, hitting or rubbing them with his snout. Eventually, claws get ripped out and the snout gets severely contused or breaks open. Thus, along with the rest of the mess you find in his enclosure, you need to clean dried blood off the enclosure, furnishings, and your very unhappy iguana.


Think like an iguana and you'll easily be able to figure out what's wrong!

Related Articles

Housing Multiple Iguanas

Iguana Care, Feeding and Socialization

Iguana Skin Color

Moving and Vacation Stress

Reptile Skin Shedding

Signs of Illness & Stress

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