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

Green Iguana: The Ultimate Iguana Owner's Manual

Book Review

Melissa Kaplan, Reptile & Amphibian Magazine, January/February 1997

Green Iguana: The Ultimate Iguana Owner's Manual
by James W. Hatfield III
Dunthorpe Press, POB 80385, Portland OR 97280
ISBN 1-88346-348-3
$32.50 (+$4/US, $6/Canada for S/H)
Ph: 503-635-8222 Fax: 503-635-8405
Prices updated 5/28/98

Several years ago, I was becoming increasingly frustrated with the information available in the pet trade on the care and keeping of the green iguanas. What has been available in the pet trade ranges from grossly outdated material, often inaccurate even at the time it was originally published, to more recent material containing more up-to-date information but still with inaccuracies in the diet and lacking in-depth information on taming, health, and behavior. With iguanas still being purchased and dumped, and dying at even younger ages, it was very apparent that the information out there just wasn't worth the paper it was published on.

My own caresheets, distributed for free at education events and carried with me and handed out to whomever was in need, had already grown from a simple one page affair to four pages. This was despite the fact that the 'experts' at my then herpetological society were telling me that no one would even bother to read the information contained on a single page, let alone several densely packed pages.

The more iguana owners I spoke with, the more it became apparent that a comprehensive book was desperately needed. I went so far as to start hammering out the beginnings of a manuscript myself when I saw a small advertisement tucked away in one of the reptile magazines: iguana owners were being sought to respond to a survey. Not being particularly shy about talking about iguanas, I returned my rather lengthy response to the surveyor, Jim Hatfield.

More than 800 other iguana owners from the U.S., Canada, the U.K., and countries around the world also responded to the 50-question survey, with many sending photographs and videotapes of their iguanas; clearly, others felt the lack of good, extensive information. Jim also sent out a 30-question survey to reptile veterinarians whose practices included iguanas. This information was only part of the research conducted. Hatfield also searched and read through the available veterinary, biological, and behavioral literature on Iguana iguana. His research also included trips to Central America and around the United States to visit iguana breeding farms and research facilities. Over the ensuing years, he conducted interviews and visits with researchers, wholesalers, pet stores, product manufacturers, and breeders. Some of these discussions and research led Hatfield to himself become a researcher as he was invited to participate in research projects on iguanas in the wild in Mexico.

The result is a 644 page (plus 10 pages of index and a separate section of 16 color photographs) book that discusses the complexities, rigors, and joys of keeping--and being kept by--green iguanas.

The book begins with a very useful table of contents outlining the nine chapters, ten appendixes, and 46 tables, illustrations, and photographs distributed through the text. Sidebars and delineated sections are used to summarize key points or to highlight certain information. Comments from survey respondents, iguana researchers, and reptile veterinarians are used throughout the book to further illustrate or highlight information in the text.

Chapter 1 discusses the classification of iguanas, and gives an historical (mythological and paleontological) overview of Iguana iguana. It discusses iguana anatomy, both external body parts and internal organs and systems. The second half of this chapter addresses common thermoregulatory, communication (e.g., bobbing, posturing, secretions, etc.), movement (running, jumping, climbing), and territorial and aggressive behaviors. Besides a minor error in the labeling of the dorsal crest as the nuchal crest, this chapter gives the owner a great overview to the inner workings of the iguana as well as placing the green iguana in evolutionary history. This chapter also includes the first time a series of photographs of an assembled iguana skeleton have ever been published, as well as clearly presented anatomical drawings.

Iguanas can be sexed with high degree of accuracy at 8" svl/1 year by looking at diameter of femoral pores. In males, all the pores will be visibly enlarged from their juvenile pinpoint stage; in females, only the first 4-5 pores closest to the vent on both legs will be enlarged, with the rest of the pores running down the thigh to the knee remaining pinpoints. For some reason, this information is missing from this chapter and the chapter on breeding and reproduction.

Chapter 2 discusses the man reasons why people get iguanas as pets, and different aspects of their personality.

Chapter 3 discusses how to select an iguana and stresses the importance of having a proper environment set up before bringing the iguana home.

Chapter 4 discusses housing at great length, with Jim's custom built Ultimate Iguana Habitat plans detailed in Appendix D. One concern I have is with the implication that the ballast from the fluorescents is enough for most of the heating needs. While the ballast of several fluorescent fixtures may keep the enclosure warm enough for iguana basking and thermoregulation during the day in some parts of the temperate zone, they will not be enough during the cooler months of the year in many parts of the world where iguanas are now being kept as pets. The Ultimate Habitat does have features I have long recommended, however: shelves, not branches, for basking and lounging, a solid top, and offset ventilation panels built into the side walls.

Chapter 5 discusses feeding, a subject at which I have expounded at some length elsewhere. Food, both the selection and preparation of food items, is as important to long-term growth and development of the green iguana as the physical environment. It is also the part most often misunderstood by owners or done just plain wrong in iguana books and caresheets. Compared to the demanding environmental requirements, the complex issues surrounding diet are enough to cause the faint of heart to make a mad dash for the nearest stuffed toy lizard. By and large, Hatfield gets it right. I am uncomfortable, however, with any diet that indicates suitable protein sources as being monkey biscuits, tofu, commercial iguana food or dog food, even in amounts of less than 5%.. Jim does discuss the literature that recommends no animal based proteins be given and the problems specifically with these particular sources, and has a lengthy section on foods to be avoided which includes animal protein. My concern is those less-than-thorough readers who will just glance at the "Supplemental Protein" section, see these foods listed, and include them in their iguana's diet.

Chapter 6 discusses special care needs such as claw trimming, shedding, and exercise.

Chapter 7 discusses medical troubleshooting. Various medical problems are presented, with their symptoms and what needs to be done to correct them. Jim wisely urges iguana owners to find a reptile veterinarian experienced with iguanas before one is actually needed, and to use a vet rather than attempt home remedies that may result in a still sicker iguana.

Chapter 8 addresses what Jim calls domestication - taming, potty training, behavior modification, establishing daily routines, and more.

Chapter 9 discusses breeding behavior and reproduction. Jim states that igs need to be 10" svl to produce eggs, but sadly, smaller iguanas have also produced eggs. Their growth stunted in captivity by poor diet and environment, some females will produce eggs after they hit sexual maturity despite body lengths the size of sexually immature subadults. These females also face a higher risk of egg-binding and pregnancy-related calcium deficiency. The chapter does go into male and female behaviors, and the problems associated with the breeding season.

Some readers have commented on the reiteration of certain points throughout the book. I find nothing wrong with this as the information is given in context, with the repetition underscoring its importance. For example, D3 is discussed in Chapters 4 (housing), 5 (feeding) and 7 (medical troubleshooting). Such linking of different sections together by common themes underscores that proper iguana keeping is of necessity a holistic process.

I must confess to a personal bias: I am predisposed to like an iguana book or lecturer who spends almost as much time going into all the reasons why iguanas do not make good pets, detailing reasons why not to buy them, as it goes into proper care and socialization. Those who got what they thought was an easy-to-care-for "yuppie puppy," "mini-dinosaur" or a "lazy-man's pet" and who don't want to hear the realities of iguana keeping won't care much for this book. Beginning iguana owners and those who have been learning the hard way will appreciate the book, finding great value in it, recognizing themselves and their iguanas in the many comments and recollections throughout the text.

On a sad note, Jim's iguana, Za, died of cancer during the time Jim was researching and writing this book. Jim not only finished the book, he continues his work with iguanas with travels to Central America, continuing to talk to researchers and conservationists. The information and insights will be put to use as book buyers may sign up for a free annual newsletter that Jim will be putting out. It will contain new information he has found through his continuing research as well as comments and feedback from readers.

There is very little missing from this book. Hatfield blends together personal experience and information from his research with quotes from survey respondents, creating a work of many voices with one unifying theme: proper care of the green iguana is not a simple undertaking but , when done conscientiously, is one with many rewards.

I like this book, not the least of which may be because reading it is like reading my own iguana writings. Jim has a deep respect for iguanas and what they are capable of, and a very realistic understanding that iguanas are not simple to care for, that they are not for everyone. While I may not agree with everything he says, I do agree with just about all of it. He has done an excellent job in presenting a huge amount of material in an easy to read, easy to understand, and easy to access manner.

And now, a word from the publisher...

Amanda Iles, Associate Publisher, reviewed my review and wrote the following comments I thought I would post here.

In the review under Chapter 4 you say, "One concern I have is with the implication that the ballast from the fluorescents is enough for most of the heating needs. While the ballast of several fluorescent fixtures may keep the enclosure warm enough for iguanas basking and thermoregulation during the day in some parts of the temperate zone, they will not be enough during the cooler months of the year in many parts of the world where iguanas are now being kept as pets." I have a few comments to clarify some misconceptions about this statement.

The habitat described has been functioning here in Portland for more than five and a half years. Oregon gets very cold. Last week and last year there was significant snow outside in the yard.

In addition to the heat generated by the fluorescents, the habitat has a ceramic heater like the one described on pages 186-187: "This new and exciting concept [ceramic heater] is an integral part of the Ultimate Iguana Habitat design...."

Page 186 says: "As you will recall, however, the design of the Ultimate Habitat generates and maintains its temperature as a result of its insulation and the heat generated by the full-spectrum light fixtures. As a result, with this design you need to provide supplemental heat only at night and during particularly cold temperatures, at which time the supplemental heater comes on briefly during the day to maintain the proper heat level."

Page 609 (Appendix D) reinforces this concept (and others): "IMPORTANT: The Ultimate Habitat is designed to function with thermostats, cooling fans, backup heater..."

On page 608 the "NON -FREEDOM" DOOR is explained: "To hold the heat in the habitat during the winter, I put a piece of Plexiglas (1/8") on the front, held in..."

The paragraph on page 609 [close to the bottom of the page] explains the limitations of the Ultimate Habitat, and how this habitat will work in any state, in any cold-weather condition -- if you follow the guidelines. "The habitat operates in our living room (15' X 25') where temperatures never drop below 68 or 69 F or get above 80 F. Under these conditions, the upper ledge area in the habitat stays at about 90 F, the next level down is about 85 F, and the bottom is about 80 F. Any temperatures above or below the tested baselines might cause problems for your habitat and lizard. Keep your room within the tested temperatures and you will have a very reliable habitat."

And Jim has his bases covered for people who live in an area that is hot all the time; see the sidebar on page 603, Non-Insulated Wall.

In addition, Jim makes it clear that he is not trying to force people to use only his Ultimate design. On page 167 (middle of the page): "Whatever housing approach you decide to take, the information in this chapter is intended to help you create a happy, safe, and healthy place for your iguana to live."

So you can see, the Ultimate Habitat will work in any climate, IF the procedures are followed. Thanks for bearing with me through all of the details. I think you are the kind of person who wants the truth, no matter how many pages you have to read.

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