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IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 39SPINY-TAILED IGUANAS: CAPTIVE CARE

Acquisition and Acclimation
A number of factors must be considered before acquiring a
Spiny-tailed Iguana (Ctenosaura spp.), the most important of
which is making the long term commitment involved in caring
for a lizard that can survive 20 years or more. Since the survival
and health of the iguana is completely dependent on the qual-
ity of care provided by the owner, he or she must consider future
changes in his or her own life and the necessary accommoda-
tions that must be made to properly maintain these animals.
Some species grow very large (over 1 m in total length), although
others remain small (less than 25 cm in total length). Potential
owners must recognize that a hatchling of one of the larger
species can grow to a meter in length within 2–3 years and will
require very roomy quarters.

A qualified reptile veterinarian experienced in iguana care
should be located to provide general health checks as well as
emergency services, should those be required. Provision also
must be made for an alternate caretaker should the owner be
away or unable to provide care. Accurate records should be kept

H U S B A N D R Y

Ctenosaura nolascensis is long-lived and can become large. Prospective owners must give consideration to providing an enclosure of sufficient size
and care for an extended period of time. Photograph by John Binns.

Spiny-tailed Iguanas: Captive Care1

Gunther Köhler1, AJ Gutman2, and John Binns3

1Forschungsinstitut Senckenberg, Frankfurt a/M, Germany;
2West Hartford, Connecticut, USA; 3San Jose, California, USA

1 Adapted and expanded from Köhler, G. 2002. Schwarzleguane.
Lebensweise, Pflege, Zucht. Herpeton Verlag Elke Köhler, Offenbach,
Germany. Most changes reflect the different realities of European and
North American ctenosaur husbandry. Different products necessary
for proper care are available and, although several species are com-
monly kept in Europe, most Americans keep only Ctenosaura similis,
a large and frequently aggressive form.



for each animal, including weights, measures, diet, and emer-
gency telephone numbers.

Spiny-tailed Iguanas and Green Iguanas (Iguana iguana) dif-
fer in their captive care requirements. Ctenosaurs have a very dif-
ferent disposition than Green Iguanas, although this is a general-
ization and temperament will vary from one individual to another.
One of the reasons for the popularity of Green Iguanas is their
predominantly friendly and sociable nature; most animals will
become quite tame over time with proper handling and care, and
(with reasonable precautions) are easily handled, much like any
“normal” house pet. In contrast, certain species of Spiny-Tailed
Iguanas can be quite wild and difficult to manage. Tremendous
patience and effort may be required in order to modify the behav-
ior of such an animal. Some of the smaller species may be easier
to work with, but only rare individuals will become sufficiently
tame that they can be taken out of their enclosures. The chances
for successfully taming an individual are much better when deal-
ing with juveniles than with subadults or adults.

Spiny-tailed Iguanas produce relatively small, hard, dry
fecal pellets, whereas Green Iguanas will excrete a far greater vol-
ume of solid waste, not to mention a considerable amount of
fluid. For this reason, a Green Iguana habitat, out of necessity,

must be easy to clean, and its aesthetic appeal can be no more
than a secondary consideration. In contrast, an attractive natural
environment can be created for a Spiny-tailed Iguana with less
concern for hygienic problems or overpowering odors. Still, the
enclosure should be designed to facilitate regular maintenance,
especially when keeping larger Spiny-tailed Iguanas, which are
prone to rearranging their cage furnishings. Changes in fecal
consistency from a relatively dry to moist/runny deposits sug-
gest a dietary imbalance or improper thermal gradient within
the enclosure.

The time commitment for one male and one or two
females will be a minimum of 30–60 minutes a day (food prepa-
ration, cleaning food and water dishes, and general mainte-
nance). If problems arise (incompatibility or illness) or if the ani-
mals are breeding (egg laying, incubation, hatching), the time
commitment increases accordingly, particularly if any of these
situations require the setup and maintenance of extra enclosures.

40 IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 KÖHLER, GUTMAN, AND BINNS

An outside view of an enclosure’s UV-transmittable window and one
happy iguana. A “room with a view” and sunlight does wonders for
captive animals. Photograph by John Binns.

Terry-cloth towels are useful in handling less manageable animals by
reducing the need to tightly clutch the animal. This reduces the stress
of handling and the towel provides protection from the Spiny-tailed
Iguana’s sharp spines and barbed tail. Photograph by John Binns.

This simple display uses beach wood, artificial plants, fake cement
stone, and corrugated tubing (hidden). The beach wood was arranged
to provide multiple basking spots and careful stacking of parts ensured
that they would not collapse. The feeding dish and water bowl are to
the left of this photograph. Photograph by John Binns.



IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 41SPINY-TAILED IGUANAS: CAPTIVE CARE

A number of ctenosaur species have been bred successfully
in captivity, some with regularity and others less frequently. In
any case, acquiring captive-bred animals is always preferable.
Acquiring wild-caught animals only encourages the importation
and exploitation of iguanas and limits the chances of the species’
long-term survival in their natural habitats. Wild-caught animals
are highly stressed, frightened, often ill (particularly due to heavy
parasite loads), and their chances for survival are minimal. This
is compounded by their fearful and flighty nature, resulting in a
reluctance to eat and a host of other problems. Of those that do
survive, all will remain wild and their life expectancy will be
greatly shortened. Although captive-bred animals are not always
parasite-free, they are considerably more stable, primarily due to
having had fewer negative encounters with humans. Their
behavior likely will be calmer and more trusting. Nevertheless,
juveniles inevitably will acclimate more quickly than adults.

The territorial nature of Spiny-tailed Iguanas needs to be
considered when deciding the number of animals to place in a
single enclosure. Sex is not easily determined in very young
ctenosaurs and, although a male and a female or a pair of young
females are more likely to be compatible, and two males will def-
initely fight, no combination of numbers or sexes will assure that
the animals will co-exist without some altercations. The size of
the enclosure (generally “bigger is better”) may be the deciding
factor in providing sufficient territory for more than one animal.
Introduction of animals into their new enclosure requires close
observation to ensure compatibility. Dominance develops at a
very young age, and can range from establishing a natural peck-
ing order to violent biting and life-threatening aggression. A sec-
ond enclosure must be available should the dominant animal
create an unhealthy, irresolvable situation with its mate or other
female animals in the enclosure.

On the positive side, competition for food may encourage
others in the group to eat more than they would if they were
held alone. A bolder and more curious individual may prompt
others in the group to behave likewise, thus creating a healthy
environment. Continuous monitoring of the behavior of either
an individual or a group of animals is a key element of good hus-
bandry.

Several tips may facilitate acclimation: (1) The habitat
should be elevated so that the animals are at eye level with their
caretakers. (2) Enclosures that open only at the top, such as refur-
bished aquaria, are ill-suited for iguanas. Many natural predators
of young iguanas’ (raptors!) attack from overhead, thus they
instinctively fear anything coming from above. (3) The habitat
should ultimately be set up in a high-traffic area as this helps to
acclimate the animals to the presence of humans, making inter-
action with their caretakers less stressful. However, allowing 2–3
weeks after quarantine for the animals to first acclimate to their
new habitat and/or new companions in order to reduce the high
stress of translocation may be beneficial before they are moved to
a more active area. Children should be cautioned not to handle
or irritate the iguanas (e.g., by banging on the glass). (4) Owners
should take time daily to tend to the animals while both animals
and owner are calm and relaxed. Sit by the habitat and just
observe them. The animals, in turn, will be able to observe their
caretaker while at a safe distance. After a few days, when you feel
that the iguanas have become somewhat accustomed to your
presence, you can carefully slide open the enclosure and deter-
mine if further interaction is feasible. Some animals can be
handfed without any difficulty, but others will be just as prone to
attempt an escape or bite an intrusive finger.

Even if the new owner is experienced in iguana husbandry,
newly acquired iguanas should be thoroughly examined by a
qualified reptile veterinarian and quarantined until results of the
examination are known and any required treatments have been
successfully completed. This must precede any introduction into
an enclosure with other animals. This examination typically
entails a blood test, a fecal sample to determine if parasites are
present, and a check for mites and ticks, injuries, swellings, and
skin lesions. The results of the series of tests will determine the
overall health of the animal and, should treatment for illness or
parasites be required, the veterinarian will either suggest regular
visits to administer the medication and treatment, or provide
you with detailed instructions for treatment at home. Some
types of parasites are fairly easy to eliminate, but for others, treat-
ment can be expensive and lengthy, and the medications are not
always well-tolerated by the animal. To determine if the parasite
treatment was successful, the veterinarian must rerun the para-
site test (fecal sampling). The veterinarian can provide guidance
regarding the necessary quarantine period.

A small auxiliary enclosure that provides all the environ-
mental needs for the animal is preferable for quarantine.
Treatment often requires elevating the ambient temperature and
humidity within the enclosure, and a smaller enclosure permits
easier maintenance of a constant temperature and a larger water
bowl can be used to increase humidity through evaporation in
the heated environment. The use of an auxiliary enclosure also
prevents internal and external parasites and bacteria from conta-
minating the main enclosure, and it is best constructed of a mate-
rial that is easy to clean and disinfect. Disinfecting agents con-
taining peroxide or alcohol should be used to clean habitats and
equipment. Under no circumstances should products containing
phenols or other toxic agents be used. The enclosure should be
void of all non-essentials items, containing only food and water
bowls and an absorbent material for waste management. Bowls
should be washed with antibacterial soap and thoroughly rinsed

These paired Ctenosaura acanthura often share the same basking spot
and are rarely apart. Photograph by John Binns.



with fresh water after each use. Waste from the animal should be
removed immediately and clean substrate provided.

Healthy Spiny-tailed Iguanas typically exhibit lively and
inquisitive behaviors. During the active phase (daytime), the ani-
mals eat, threaten, court, or patrol their territory with alternat-
ing periods of basking or sleeping. Sick animals, on the other
hand, will have sunken eyes and protruding pelvic bones due to
loss of weight, and lack muscle on the legs and tail. They tend
to lie apathetically at the bottom of the enclosure and do not
react to their surroundings. Any movements tend to be halting
and insecure and the lower abdomen often rests on the ground.

The importance of regular observation cannot be overem-
phasized. Behavioral changes could indicate illness or other
problems for which treatment should be sought and adminis-
tered immediately. Animals in the wild will instinctively conceal

signs of illness to avoid attracting predators, reinforcing the need
for careful observation.

Distinguishing the Sexes
In fully-grown males of most ctenosaur species, the dorsal crest
is substantially more developed than in females. Exceptions are
C. alfredschmidti, C. clarki, C. defensor, and C. flavidorsalis, in
which neither males nor females have particularly well-devel-
oped dorsal crests. Adult males also usually have clearly visible
hemipenial bulges under the base of the tail. Another important
character for determining gender is the size of the femoral pores,
which are always larger in males than in females. In adult male
C. similis, the femoral pores can attain diameters of 2.5 mm,
whereas they are rarely more than 1 mm in diameter in females.

Housing
The size of the enclosure will determine the degree of flexibility
in design and setup. Planning must include provisions for animal
barrier isolation and for developing lighting and temperature zon-
ing for thermoregulation. In order to adequately provide for a
complete behavioral repertoire, a ctenosaur enclosure must be
large and sturdy. For an adult pair of any of the medium-sized or
large species (subgenera Ctenosaura and Loganiosaura; see Köhler
et al., IGUANA 10(3):79–81), a habitat should be at least 200 x
150 x 130 cm. For the smaller species (subgenus Enyaliosaurus),
the minimum size would be 80 x 60 x 90 cm. As is the case with
all medium-sized to large iguanas, space planning for adult sized
animals is critical when initially considering the enclosure design.
If the animals have been previously paired and are able to com-
fortably co-exist, the recommended enclosure size should be suf-
ficient. However, if a male and female are purchased individually
and are subadults or older, a second enclosure should be available
in cases of incompatibility.

Hatchling Spiny-tailed Iguanas are best housed in groups
of three or four in at least a medium-sized terrarium about 60 x
40 x 60 cm in size. Certain juveniles in captivity, like their coun-
terparts in the wild, can be distinct loners and may be incom-
patible with other individuals. A well-structured terrarium with
multiple basking spots and hiding places is required for raising
juveniles together. Sometimes, however, despite all these mea-
sures, combatants must be separated to avoid injuries.

Setup
Because Spiny-tailed Iguanas are territorial, the habitat should
be structured to permit animals to avoid one another, particu-
larly if individuals vary in size. Visual barriers and hiding places
can be created using rocks, tree roots, corrugated-drain tubing,
cork tubes, or whole pieces of cork bark attached to walls. All
structures and components need to be sufficiently secured and
stable to prevent damage to the component or injury to the
iguanas.

Isolation barriers may necessitate the provision of individ-
ual basking areas, and this should be considered when develop-
ing the enclosure design. Basking locations should be designed
to incorporate a declining temperature zone for proper ther-
moregulation. This entails creating a surface that allows the ani-
mal to adjust its position relative to the central “hotspot” (high
temperature areas) in order to maintain the correct body tem-

42 IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 KÖHLER, GUTMAN, AND BINNS

Sandblasted wood branches and some artificial plants keep a display
from looking bare. This enclosure uses commercial plastic paneling
that facilitates cleaning and adds a level of thermal insulation. All seams
are sealed to minimize problems with ants and other insects. The win-
dow is UV-transmittable glass, providing a substantial amount of nat-
ural sunlight during the day. The vent at the top extracts air from the
enclosure with a fan to help minimize odor and draw fresh air into the
enclosure through vents at the bottom. An additional heat-lamp that
was installed for the winter months is barely visible at the top of the
window. Photograph by John Binns.



IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 43SPINY-TAILED IGUANAS: CAPTIVE CARE

perature. In the wild, animals can maintain body temperature
within a few degrees by repositioning themselves between bright
sun and shade or retreating into cooler burrows. Providing tem-
perature zones is a mandatory habitat design element to ensure
good health. Since iguanas require heat to effectively digest food,
inadequate thermal design of the enclosure will limit the bene-
fits of providing a healthy nutritional diet, even with the pres-
ence of sufficient ultraviolet (UV or UVA/B) light.

In areas other than hotspots, the use of artificial rock can
appear very natural and has the advantage of being light and rel-
atively easy to clean. Artificial rock or structures can be pur-
chased from most large pet suppliers. As an alternative for those
who prefer a more “natural” setting, artificial props such as rock
can be constructed. The base material of an artificial rock or
prop can be made from styrofoam blocks, which are easily
carved into shape with a hot knife or carving tool. The entire
surface can then be covered with plaster mixed with a naturally
colored powder and then modeled appropriately with a wet
brush. Sharp edges should always be avoided. While still damp,

the plaster can be covered with sifted sand to give the appear-
ance of sandstone or left bare to represent some other natural
rock. Covering the structure with sand helps reduce sharp edges,
but it also makes cleaning more laborious and should be used
only in areas unlikely to become soiled. The use of any poten-
tially toxic or petroleum-based materials in the construction of
props must be avoided.

Each component used in the enclosure should be cleaned
or washed prior to use or assembly. Additionally, if the enclosure
is located where insects, ants, parasites, and other undesirables
might invade, some provision for preventative maintenance
should be considered. Elaborate, natural-appearing habitats can
be extremely difficult to rid of pests, often requiring complete
disassembly to solve the problem. A preventative measure to
consider during the design phase, especially if ants are a recur-
ring problem, is construction of the enclosure so that it is ele-
vated off the ground and the structure’s waterproofed support
beams fitted into a water reservoir to create an isolation barrier.
Ants are of particular concern during the egg-laying season.

Sanitized driftwood or tree-limb sections obtained com-
mercially combined with artificial plants are excellent enclosure
components for providing physical isolation, and will allow ani-
mals to move from one level to another while making effective
use of the three-dimensional space. Combined with artificial or
natural rocks, these can produce a very naturalistic environment
and simultaneously provide for the needs of the iguanas.

An inexpensive alternative to burrow construction is black
plastic corrugated drain tubing, which is available in various
diameters. The corrugated tubing also is useful when handling
more intransigent animals. If this tubing is employed as the pri-
mary “burrow” or “hiding chamber,” the animal will readily
accept it and use the tube as a secure hiding location or as a sleep
chamber. Once the animal is in the tube, both ends can be cov-
ered by a gloved hand, and the animal can be easily and safely
transported to another location or holding pen. This method is
extremely useful in transporting excitable or unruly animals
from the main enclosure to an outside cage for sunlight expo-
sure. Once the sun goes down, the animal retreats naturally to

This female Ctenosaura acanthura will climb on her log to bask under
UV lamps and comfortably wedge herself inside it to sleep at night.
Photograph by Carole Saucier.

Gradient temperature zoning is
necessary for proper thermoreg-
ulation. The iguana under the
basking lamp enjoys a tempera-
ture ranging from 45–36 °C,
whereas the iguana on the left is
exposed to a temperature rang-
ing from 36 °C to ambient
enclosure temperatures of
28–33 °C. The thermal-spread
from the basking lamp to the
enclosure’s floor (indicated by
the light gray triangle) is con-
trolled by adjusting the height
and/or wattage of the lamp.
Basking lamps should have
reflectors and protective screens.
Illustration by John Binns.



its “tube,” and it can then be transported back to the main
enclosure with minimal disturbance and stress.

Cork tubes also make good habitat furnishings. They pro-
vide iguanas with traction for climbing and are readily accepted as
sleeping places. For smaller species, the enclosure can be attrac-
tively decorated with Yucca and other robust plants. Enclosures for
juveniles also should include plants, as these help retain humidity.
For adults of the larger species (e.g., C. similis, C. melanosterna),
plants only make sense if the habitat is large enough to ensure that
they are out of the iguanas’ reach. Otherwise, the plants will be
either eaten or trampled in very short order. Artificial plants are a
hardier and still attractive alternative.

A food bowl can simply be placed on the bottom of the
enclosure. The use of commercially available garden cement tiles
or walkway liners that keep the bowls from being upset will aid
in housekeeping. Some animals, however, will not readily
descend from an elevated perch, and are much more likely to eat
if their food is placed higher. Driftwood structures can be used
to construct a secondary platform higher in the enclosure.

Although adult Spiny-tailed Iguanas normally meet all of their
fluid requirements from the food that they eat, a water bowl
should always be provided — and cleaned daily. In cases where
territorial disputes occur, assuming the disputes do not result in
injury, separate food bowls and water dishes can be used to min-
imize conflict.

A mixture of sanitized soil, sand, and cypress bark mulch
comprises an appropriate substrate when simulating a natural
environment. The use of unprocessed soil, sand, and bark mulch
is not recommended due to the potential of introducing insects,
bacteria, or other undesirable elements. For those concerned
about maintenance, the use of artificial turf can be employed
with minimal impact on the natural appearance of the enclo-
sure. In essence, once the enclosure props are established, artifi-
cial turf floor inserts can be constructed and used as substrate
pads. These can be secured using snaps, Velcro©, or quick-
release locking devices. The artificial turf pads can be duplicated
and replaced for ease of cleaning and maintenance. Wood shav-
ings, corn based substrates, and newspaper are not recom-

44 IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 KÖHLER, GUTMAN, AND BINNS

Inexpensive corrugated drain tubing comes in various sizes and can be
used for burrows and retreats. Tubing helps reduce territorial disputes
by providing ample hiding places and allowing each individual to take
ownership of a tube. Photograph by John Binns.

A well-secured Spiny-tailed Iguana (Ctenosaura nolascensis), safely
buried in his “burrow,” makes for easy transportation. Photograph by
John Binns.

Corrugated drain tubing can be used to transport aggressive Spiny-
tailed Iguanas. The tube provides a sense of security, minimizing stress
for the iguana, and, most importantly, reducing the chances of getting
bit (note the use of heavy gloves). Photograph by John Binns.

Corrugated drain tubing distributed around the enclosure provides pro-
tection from a dominant animal and serves to visually isolate individuals.
The tubing can be placed under or behind an enclosure’s artificial props
to enhance the aesthetics of a “natural” setting. Photograph by John Binns.



IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 45SPINY-TAILED IGUANAS: CAPTIVE CARE

mended; they are impractical and lack aesthetic appeal. Wood
shavings can be accidentally ingested and can result in life-
threatening intestinal impaction.

Hatchling terraria should be furnished with branches, a
plant, small roots, several tubes of cork or corrugated plastic, a
water dish (10–15 cm in diameter, water temperature 25–30 °C),
and a heat emitter (80 W) and fluorescent tube for heat and light.
A heating mat may be used to warm the water bowl from below.
Hatchlings have a much higher fluid requirement than adult
iguanas and should be provided with sufficient drinking water.
Water bowls should be cleaned and filled daily and the terrarium
misted regularly.

Heat and Light Requirements
Spiny-tailed Iguanas will be fully active and can display their
intense coloration only with proper illumination. The daily pho-
toperiod (light time) will vary by season and according to the
geographic origin of the species. Regulating a consistent pho-
toperiod as well as appropriate daily temperature fluctuations in
the enclosures is recommended. To simulate the 24-hour cycle,
the method of controlling light and heat should be considered
prior to setting up the enclosure. Many commercially available
“timers” can individually control lights and thermostats used to
control the heat source, or more sophisticated electronic con-
trollers are capable of simulating a complete 24-hour cycle (light
and heat) from sunrise to sunset. Whichever method is used,
installation will require careful planning. Specifics are variable,
depending on the type of light and heat sources, power require-
ments, reliability, costs, and aesthetic considerations.

Light can be broken down into three basic categories: (1)
ultraviolet or UVA/B light is required for iguanas to produce vit-
amin D3 (see also Bogoslavsky, Iguana Times 9(1–2):32–34 and
MacCargar, IGUANA 10(3):82–85), (2) visible light reflects the
combined color spectrum that collectively produces white or
full-spectrum light, and (3) infrared light, which is essentially
heat and is invisible to the human eye. A current trend is to
combine the UVA/B and visible light spectra, and this has been
successful to some degree. The types of artificial lighting avail-
able for purchase vary depending on location, and the charts
provided in this article feature some of the products available in
the United States. Although many products are readily available,
Ctenosaura (and other iguanas) require higher levels of UVA/B
than most other reptiles; therefore, the products selected should
include lamps that produce sufficient quantities of light in the
UV range. Regular ultraviolet (UV) light is critical for proper
calcium metabolism and breeding.

The selection of lighting itself is complex and often con-
fusing. Aside from determining which type of bulb to use, ques-
tions regarding fixture types, location, and mounting must be
addressed. With effective planning, the various requirements
(lamp types) for proper illumination can be minimized. Factors
to consider in planning for proper illumination include locating
the UVA/B lamp within its effective range relative to where the
animal is likely to spend the greatest amount of time, the loca-
tion of full spectrum lighting to best provide overall illumina-
tion of the enclosure, and basking spot lamp location or loca-
tions that facilitate the temperature zone concept mentioned
previously.

Cement garden tiles or walkway borders, which are useful for securing
food dishes, also may serve decorative purposes. These cement pieces
are lighter than natural stone and allow considerable flexibility when
designing an aesthetically pleasing enclosure. Photograph by John Binns.

This male Ctenosaura flavidorsalis was much more inclined to feed reg-
ularly when the food dish was secured in an elevated position.
Photograph by Gunther Köhler.

A young Ctenosaura similis peeking out of a cork tube. Cork tubes pro-
vide iguanas with traction for climbing and are readily accepted as hid-
ing and sleeping places. Photograph by Gunther Köhler.



Mounting of lamps is not restricted to the ceiling of the
enclosure, which in very large enclosures would require lamps of
very high wattage in order to be effective at floor level. To reduce
the overall power requirements (wattage) of each lamp, suspen-
sion is an effective method. Suspension also enables height
adjustments to fine-tune heat and UV delivery. Naturally, pre-
cautions must be taken to prevent animals from coming into
contact with suspended fixtures and to ensure that all heat-pro-
ducing sources have protective screening. Essentially, lower
wattage UV and basking lamps can be located closer to the floor,
whereas general full-spectrum illumination is mounted high in
the enclosure. In some cases, the use of a single, high-power full-
spectrum lamp such as sodium, mercury or metal-halide lamps
in the 250-watt range is less costly than employing four 100-
watt full-spectrum lamps dispersed around the ceiling of the
enclosure.

Precisely calculating the proper lamp wattage can be diffi-
cult, especially if the enclosure has a complex layout. One alter-
native is to first select lamps of various wattages and, through
testing, discover the right combination to produce the desired

effect. Changing the wattage of lamps may be required to com-
pensate for changes in ambient temperature or seasonal varia-
tions. For most types of lamps, wattage effectively translates into
the ability to produce heat. However, in UVA/B lamps, wattage

46 IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 KÖHLER, GUTMAN, AND BINNS

This custom light fixture employs UV, full spectrum, and heat lamps
(including a “moon” light). Custom fixtures help reduce unsightly
wiring, adjustable reflectors, and screened protection for the animal.
This fixture uses electrical conduit to eliminate exposed wiring.
Photograph by John Binns.

This elaborate electronic habitat control system automatically controls
32 enclosures; two of those electronic control units are shown in the
photograph. This system controls the lighting to simulate sunrise by
slowly increasing to full intensity. Then, at a selected time, simulates
sunset by slowly decreasing intensity until dark, at which time simu-
lated moonlight is activated. The system also controls ambient tem-
peratures that correspond to day and evening settings. Should any of
the presettings fail or exceed limits, an audible alarm is activated and
an auto-dialer sends a message to a beeper. A muffin-fan is activated if
the enclosure overheats. All the lamps are turned off until the ambient
temperature reaches safe levels. Photograph by John Binns.

Large outside cages on rollers are an excellent means of providing “nat-
ural” basking sites. Cages can be repositioned easily in sun or shade and
the relatively large size allows an animal to reposition itself for the most
effective thermoregulation. The black foam floor mat that takes up
about half the shelf collects heat to provide a hot spot. The other half
of the shelf is wire-mesh and is much cooler. During the summer
months, a portion of the top of the cage is covered to provide shade.
Photograph by John Binns.



can be misleading relative to their ability to produce heat, which
is significantly less than a comparable visible spectrum lamp of
the same wattage.

Selection of lamp type should be based on performance,
longevity, and aspects of enclosure design such as size, shape, and
materials (hard-walls, wire-screen, etc.) used. In general, as the
size of the enclosure increases, so does the requirement for light
and heat (wattage). For small indoor enclosures, in which ambi-
ent temperatures remain relatively constant, the amount of heat
produced in lamps must be checked and allowances made for
adequate air-ventilation to prevent the enclosure from overheat-
ing. Conversely, maintaining temperatures within allowable lim-
its within a screened enclosure located in an area that is subject
to large ambient temperature fluctuations can prove to be a chal-

lenge. This situation often leads to the use of additional heat
sources and controllers to compensate for temperature variations.

As a final word on illumination, no light supplement for
captive animals is better than natural sunlight. Regular periods of
exposure, when possible, should be employed. In designing
enclosures, any access to natural sunlight (window, porch, sky-
light, etc.) should be optimized. To utilize the sun’s UV, glass and
plastics need to be replaced with UV-transmittable substitutes.

Ambient temperatures in an enclosure should range from
28–33 °C during the day and be reduced to 18–24 °C at night.
Heat can be generated by the lamps illuminating the enclosure
as well as by specific heat producing lamps or ceramic heaters.
During the peak summer season, the total illumination wattage
may need to be reduced in order to keep the enclosure within

IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 47SPINY-TAILED IGUANAS: CAPTIVE CARE

ULTRAVIOLET OPTIONS
Mercury Vapor Bulbs and Fluorescent Tubes

Mercury Vapor Lamps emit a higher intensity of UVB with added benefits of UVA and full-spectrum light that help the animal produce vitamin
D3 to aid in balanced calcium metabolism. All lamps are rated for use at distances from 30 cm to about 2 m. The optimum distance is about 1 m
from the bulb lens. These bulbs do emit a fair amount of heat, but less heat than an incandescent bulb of comparable wattage.

Manufacturer Brand 100 Watt 160 Watt 250–275Watt 100 Watt 160 Watt 
Name Flood Flood Flood Spot Spot

Zoo Med PowerSun UV PUV-11 PUV-10 — — —

T-Rex Active UV 82404 82406 82408 (275w) 82414 82416

Full Spectrum R40 Frosted FSUV100 FSUV160 FSUV250 — —
Solutions

Premium Life Mercury Vapor PI12000 PI12001 — — —
Globe

Fluorescent Tubes emit UVB with added benefits of UVA and full-spectrum light with very little heat. About 5–8% of the total energy output is
in the UVB wavelengths, which helps to prevent metabolic bone diseases. Fluorescent tubes should be used with an incandescent (day or night)
supplement to create an acceptable thermal gradient. All lamps are rated for use at distances from 25–30 cm. The optimum distance is 15–25 cm
from the tube.

Manufacturer Brand 14 Watt, 15 Watt, 20 Watt, 30 Watt, 40 Watt, 40 Watt, 
Name 15” Tube 18” Tube 24” Tube 36” Tube 42” Tube 48” Tube

Zoo Med Iguana Light 5.0 FI-15 FI-18 FI-24 FI-36 — FI-48

Hagen Exo Terra PT-2159 PT-2160 PT-2161 PT-2163 PT-2164 PT-2165
Repti-Glo 5.0

Hagen Exo Terra PT-2169 PT-2170 PT-2170 PT-2173 PT-2174 PT-2175
Repti- Glo 8.0

ESU Reptile Desert — RP393 RP390 RP391 — RP392
7% UVB

ESU Super UV RP454 RP453 RP450 RP451 — RP452
(3%UVB + 
7%UVA)

Vita-Lite — — VL-06402 VL-3028 VL-1064 — VL-06418
(also has 75w, 
96” tubes)



allowable temperature limits. If using lower wattage bulbs, pro-
viding increased ventilation, and eliminating other sources of heat
proves ineffective, air-conditioning may be necessary.

The central zone of the main basking area should have a
hotspot reaching 45 °C. This can be produced using a single
lamp source or combination of lamps such as spotlights, infrared
lights, ceramic heaters, and UV lights, depending again on the
particular design of the available lamps and the nature of the
enclosure. Further considerations must include a declining tem-
perature zone on an approximately level plane from the central
hotspot to the ambient enclosure temperature of about 28–33
°C. Although possibly restricted by limited space, the more grad-
ual the decline in temperature, the more latitude the iguana will
have in selecting the proper temperature zone. The temperature
gradient can be established by adjusting the height of the bask-
ing spot lamp or lamps. Raising and lowering the basking lamps
may require a change in wattage to produce the desired temper-
ature. The use of other basking spots can be incorporated at
higher levels of the enclosure, but these do not need to be as
finely tuned as the main basking spot.

For most species, the relative humidity during the day
should be about 50–60%, climbing to 70–80% at night. For
particularly low humidity locations, a plastic tub filled with
water can be used to increase humidity by evaporation. During
the rainy season (May to November), depending on the ambi-
ent humidity where you live, the entire habitat should be thor-

48 IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 KÖHLER, GUTMAN, AND BINNS

VISIBLE LIGHT OPTIONS 
(INCANDESCENT DAYLIGHT)
Daylight Blue and Basking Spot Bulbs

Incandescent bulbs emit full-spectrum light, limited UVA, and an abundance of heat. Flood lamps create a larger heated area and spot bulbs
create a more concentrated heated area.

Flood Bulbs

Manufacturer Brand Name 40 Watt 60 Watt 100 Watt 150 Watt

Zoo Med Daylight Blue DB-40 DB-60 DB-100 DB-150

T-Rex Day Blue TR82322 TR82330 TR82332 TR82334

Hagen Day-Glo PT-2104 PT-2110 PT-2112 PT-2114

Hagen Exo Terra Sun Glo PT-2111

ESU Brightlight RP409 RP410 RP411 RP150

Spot Bulbs

Manufacturer Brand Name 50–60 Watt 75 Watt 100 Watt 150 Watt

Zoo Med Repti Basking SL-50 SL-75 SL-100 SL-150

Zoo Med Repti Halogen HB-50 HB-75 HB-100 HB-150

T-Rex Basking Clear TR82390 TR82394 TR82396

T-Rex Daylight Blue TR82360 TR82362 TR82364 TR82366

Hagen Exo Terra Sun Glo Basking PT-2131 PT-2132 PT-2133 PT-2134

Hagen Day-Glo Basking PT-2135 PT-2136 PT-2138 PT-2140

ESU Reptile Brightlight Spot RP413 RP414 RP415

Vita-Lite Basking Spot DL4644 DL4647

Air conditioning was necessary in this vivarium to solve the problem
of overheating during the summer months. This particular vivarium
houses a variety of species, each with specific ambient temperature
requirements that could not be solved by lowering lamp wattage. The
skylight above the compact air conditioner brightly illuminates the
inside of the vivarium during daylight hours. Photograph by John Binns.



IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 49SPINY-TAILED IGUANAS: CAPTIVE CARE

oughly misted at least once a day to simulate rainfall. Enclosure
components should be able to withstand misting and electrical
components should be avoided. During the dry season, misting

two or three times each month is sufficient. Ctenosaura bakeri is
an exception and has some very specialized care requirements,
as their natural habitat is wet mangrove swamp (see, for exam-
ple, Gutsche, IGUANA 10(2):28–29).

Population Density and Socialization
Adult males cannot be kept together. They are territorial and are
likely to injure each other. A single male with one or two females
can be housed together. Incompatibility and biting is sometimes
observed even between females, and separating them into indi-
vidual enclosures may be unavoidable. Juveniles of the larger
species tend to be particularly quarrelsome. Usually, one indi-
vidual will quickly assume the dominant position and begin to
oppress the other lizards. In order to ensure that all animals
thrive, any that are repeatedly chased away from food and bask-
ing spots must be separated. Juveniles should never be held with
adults, as they may be regarded as prey.

The larger species of ctenosaurs can be kept with Green
Iguanas or Tegus (Tupinambis teguixin). The smaller species,
such as C. clarki or C. defensor, can be kept with Chuckwallas
(Sauromalus) or the larger species of Spiny Lizards (Sceloporus).

INFRARED (INCANDESCENT 
LIGHT AND HEAT) EMITTERS

Incandescent night bulbs emit low levels of visible light in both flood and spot lamps (red and black glass). Infrared bulbs and ceramic heat
emitters are appropriate for nighttime use, as they generate radiant heat and little or no light.

Flood Bulbs

Manufacturer Brand Name 40 Watt 50–60 Watt 75 Watt 100Watt 150 Watt

Zoo Med Nightlight Red NR-40 NR-60 — NR-100 —

T-Rex Nocturnal Black TR82326 — TR82340 TR82342 TR82344

Hagen Night-Glo — PT-2141 PT-2142 PT-2144 PT-2146

ESU Nightlight bulb RP419 — RP 420 RP 421 RP 422

ESU Red Basking Night — RP 402 (50 Watt) RP 403 RP 404

Spot, Infrared, and Ceramic Bulbs

Manufacturer Brand Name 50 Watt 60 Watt 75 Watt 100 Watt 150 Watt

Zoo Med Infrared RS-50 — RS-75 RS-100 RS-150

T-Rex Day/Night Red TR82380 — TR82382 TR82384 TR82386

T-Rex Nocturnal Black TR82370 — TR82372 — —

ESU Nightlight Spot — RP 423 — RP 424 RP 425

Ceramic Heat Emitters

Manufacturer Brand Name 40 Watt 60 Watt 80 Watt 100 Watt 150–165 215 Watt 250–265 
Watt Watt

Zoo Med Repticare CE-60 CE-100 CE-150 CE-250

ESU Bask N’ Heat RP480 RP481 RP482 RP483 RP484 RP485 RP486

Hagen Exo Terra Heat PT-2040 PT-2045 PT-2046 PT-2047

This large Rhinoceros Iguana (Cyclura cornuta) takes full advantage of
the UV and heat lamps overhead. The “lizard hut” is used to facilitate
basking close to the lamps and also provides a sleeping site. Photograph
by John Binns.



Generally, however, species with different habitat needs or those
that may be viewed as potential prey (e.g., smaller lizards) should
not be housed with ctenosaurs. Keeping ctenosaurs together
with turtles is not recommended, since turtles often pass amoe-
bas (e.g., Entamoeba invadens), and an amoebic infection is often
difficult to treat in herbivorous lizards.

Closely related species from the same subgenus should not
be kept together for breeding purposes, because this may result
in unwanted hybridization. Accurately identifying the species
one acquires for breeding is vitally important, especially in cases
where animals are acquired from different sources. Since
Ctenosaura is not commonly kept in the private sector, a spe-
cialist should be consulted for identification. This can be done
through the use of photographs and other transmittable data.
The keeper must preclude any chance of hybridization.
Ctenosaura oaxacana and C. quinquecarinata have hybridized in
captivity. Even under natural conditions, hybridization is known
to occur between individuals from different subgenera, such as
Ctenosaura bakeri and C. similis. However, if hybrid animals
resulting from irresponsible breeding enter the pet trade or are
passed to other breeders and not identified as hybrids, this
would quickly contaminate the species’ captive gene pool.

Nutrition
Spiny-tailed Iguanas are omnivorous. Juveniles, however, prefer
animal-based foods. Between 40 and 80% of the food consumed
by young C. similis (SVL around 10 cm) consists of insects. In
contrast, adult Spiny-tailed Iguanas are predominantly vegetar-
ian. Vegetables, such as sweet potatoes, squash, and green beans,
as well as leafy greens, such as dandelions, collard greens, mus-
tard greens, escarole, and chicory are readily accepted. Various
seeds and sprouts (linseed, sunflower, soy beans), flowers (dan-
delions and hibiscus), and fruit (nectarines, peaches, pears, apples,
melon, berries, plums) are good supplements. The colors red and
yellow are particularly attractive to Spiny-tailed Iguanas (as they
are for many other reptiles), so hibiscus flowers, grated carrots,
tomatoes, strawberries, dandelion flowers, and other red or yel-

low foods are usually consumed greedily and often may be used
to convince reluctant eaters to feed.

50 IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 KÖHLER, GUTMAN, AND BINNS

Ctenosaura bakeri exhibit at the Frankfurt Zoological Garden illustrates
the complexity necessary to house a breeding group of Spiny-tailed
Iguanas in a single enclosure. Note also the large “pond,” necessary for
maintaining the high humidity critical to these mangrove swamp-
dwelling lizards. Photograph by Gunther Köhler.

This juvenile Ctenosaura similis is eating an hibiscus flower. Like many
other iguanid lizards, Spiny-tailed Iguanas respond positively to
brightly colored blossoms. These are sometimes effective in inducing
an otherwise reluctant eater to feed. Photograph by Gunther Köhler.

Unlike Green Iguanas, Spiny-tailed Iguanas are omnivorous. This
female Ctenosaura bakeri is eating a cricket in the wild on Utila Island,
Honduras. Photograph by Gunther Köhler.

This captive-bred Ctenosaura similis readily accepts a dandelion flower.
Supplementing purchased foods with items collected in the yard or gar-
den helps to ensure a varied diet. Note, however, that plants sprayed
with pesticides or other lawn chemicals are not suitable for use as food.
Photograph by Gunther Köhler.



IGUANA  •  VOLUME 11, NUMBER 1  •  MARCH 2004 51SPINY-TAILED IGUANAS: CAPTIVE CARE

Food should be offered daily and should always include as
much variety as possible (see dietary recommendations for
Green Iguanas in Barten, IGUANA 10(4):129–141; these gen-
erally apply to adult ctenosaurs as well). All food items should
be washed, chopped into small pieces, and well mixed. During
the summer, leafy garden plants (dandelions, clover, mulberry
leaves, raspberry leaves) can comprise a large portion of the diet.
During the winter, various leafy cooking greens and sprouts can
be substituted. Food remnants should be removed daily and
food bowls cleaned thoroughly. Some foods contain harmful
substances and should be fed only in very limited amounts.
These include oxalates (in rhubarb, sorrel, and spinach), nitrates
and saponin (particularly in spinach and comfrey), and goitro-
gens (in cabbage).

Animal protein should be provided 1–3 times per week.
This can include all types of commercially available insects such
as crickets, grasshoppers, wax moths and their larvae, meal
worms, superworms, and giant cockroaches.

Mineral supplements should be added to food daily. All
insects should be dusted with mineral powder before they are
offered. In addition, a regular vitamin supplement must be pro-
vided. Many vitamin supplements are available commercially,
but caution is advised. Overdosing or excessive use of these sup-
plements can result in a number of nutritional disorders.
Owners should consult their iguana veterinarian to establish a
dietary supplement program. This is especially true when con-
sidering fat-soluble vitamins, such as A and D, where overdos-
ing is particularly dangerous.

First foods offered to hatchlings should be wax moths and
small crickets. Finely chopped and well-mixed vegetables also
should be offered daily, although the little lizards will most likely
prefer the insects. Hatchlings should receive a mineral supple-
ment containing calcium. With a poor diet, fast-growing juve-
niles can develop bone disease such as rickets and fibrous
osteodystrophy, which are difficult to treat (see also Gutman,
Iguana Times 9(1–2):35–37).

References
Braun, D. 1993. Erfahrungen bei der Pflege und Zucht von Ctenosaura

palearis. Iguana Rundschreiben 12:13–18.

Köhler, G. 1992a. Artgerechte Ernährung und ernährungsbedingte
Erkrankungen des Grünen Leguans, Iguana iguana (Linnaeus 1758).
Sauria 14:3–8.

Köhler, G. 1992b. Die Bedeutung von Entamoeba invadens bei der
Vergesellschaftung von Echsen oder Schlangen mit Schildkröten. Sauria
14:31–34.

Köhler, G. 1993. Schwarze Leguane. Freiland Beobachtungen, Pflege und Zucht.
Herpeton Verlag, Offenbach.

Köhler, G. and E. Blinn 2000. Natürliche Bastardierung zwischen Ctenosaura
bakeri und Ctenosaura similis auf Utila, Honduras. Salamandra 36:77–79.

Van den Heuvel, W. 1997. De Zwarte LeguaanCtenosaura palearis in zijn natu-
urlijke omgeving en de voortplanting in het terrarium. Lacerta 55:155–159.

Van Devender, R.W. 1982. Growth and ecology of Spiny-tailed and Green
iguanas in Costa Rica , with comments on the evolution of herbivory and
large body size, pp. 162–163. In: G.M. Burghardt and A.S. Rand (eds.),
Iguanas of the World: Their Behavior, Ecology and Conservation. Noyes
Publications, Park Ridge, New Jersey.

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Self-ballasted mercury 
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All natural Iguana 
food. No artificial 
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moist pellet formula — no need to add 
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calcium/phosphorus 1:13). Available in 
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