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 Horned Lizard Care Sheet

I just submitted this under the care sheet section, but sometimes it takes a while to get posted. I know some of you have been waiting a while for this, and some people donít think to look for a "care sheet" in the "care sheet" section, so Iíll post it here too. Enjoy. Warning: It is very detailed and therefore long. Any suggestions for topics I might have missed are welcome.

Horned Lizard Husbandry
Genus: Phrynosoma

Downloadable format is available from the website linked under my profile.

Quick Horned Lizard Facts:

Diurnal - Active during the day
Desert/Semi-Desert Dwelling - Prefers warmer, more arid climate
Preferred Substrate - Sand
Requires UVB lighting
Diet - Insectivorous ( eats primarily Harvester ants )
Social to other Horned Lizards, but usually solitary
Does not prefer to be handled and does not like being watched too closely
Requires water twice weekly
Life span- Lives up to 8-12 years or more in the wild. Average is 6 in captivity with good care. One documented as living 18 years with an experienced herpetologist. Most Horned Lizards under substandard care die within months.

I. Introduction to the Genus

I have been studying & keeping these fascinating lizards for about 5 years. They are definitely not what I would recommend for a beginner. They can be difficult and fragile in captivity, especially wild caught Horned Lizards. It is strongly urged that you not buy wild caught animals. Most people selling these wild caught lizards donít have a clue about how to take care of them. So they usually come to you with diseases, parasites, and malnourished. Many die soon after you have paid your money. Wild caught reptiles that stress after capture often will not eat in their new surroundings, even starving to death in cases because they are not comfortable in captivity. A reptile that is not comfortable and feels insecure will not eat.

Horned Lizards are among the most difficult reptiles to keep alive and healthy that I have yet dealt with. The novelty, casual, or novice reptile keeper would be well advised to seek an easier herp, especially as a first. There is definitely a reason Horned Lizards have not become easily propagated and widely kept as pets, despite their very Jurassic looking appeal.

It is strongly advised that anyone considering Horned Lizards read as much as possible and become very proficient with the many care facts of this lizard before taking one on. I advocate this rule of thumb; If you can go onto a Horned Lizard web forum and can answer most of the basic general species information and captive care related questions asked by others, then you are more assured to be ready for one. This is a reptile which is not very tolerant of a "learn as you go" curve. This care sheet is meant to supplement the knowledge of the responsible keeper, who will research the animal and itís needs prior to obtaining one.

There are 14 different recognized species in North America. Most of these ( 8 ) are native to the southwestern US, though one or two species can be found in the central plains from Oklahoma to the Dakotas, and into the northwest and Canada. Though none of these species native to the US is federally protected as of yet, most of these species are state protected in many of the states they are native.

Limited health related information from Iguanidae Family applies also to Phrynosoma ( they are closely related ), i.e. stress factors and skin blackening syndrome, infections & wound care, etc. I Recommend Melissa Kaplanís information on the Green Iguana in this regard ( ). This care sheet covers only Phrynosoma ( Horned Lizards ), but much of the general husbandry and technical information contained herein is applicable to other herps.

This care sheet is applicable to the majority of Horned Lizard species, though some species, such as P. hernandesi and P. douglassi are high elevation species and will have differing dietary, humidity, and temperature requirements.

Species Identification & Distribution

As covering in detail the identification of each individual species in this genus would be exhaustive and merely duplicate that which can be found in many other good resources, I will refer the reader to the following for identification.

Sexing & Dimorphisms

Males have an easily identifiable row of yellowish femoral pores, running lengthwise along the underside of each rear thigh, and hemipenal bulges at the base of the tail just rear of the vent opening ( anal plate ). Additionally in most species just rear of the vent there will be two larger "post anal" scales, noticeably larger than surrounding scales.

Females will have a less easily defined row of pores, and have thinner tails at the base ( no bulging ). Though some species have characteristically wider tails, and may be harder to differentiate without comparison. Females also are generally larger than males, although again, experience and comparison with previous examples will help, since age can be harder to determine.

II. General Husbandry


For several reasons Horned Lizards do much better in outdoor housing if the climate suitably approximates their home climate. For geographical locations that do not provide adequate climate and sunlight intensity, as in basking temperatures or UV, a more enclosed environment with artificial lighting and heating, or a completely indoor setup will be required.

For outdoor enclosures it is important to ensure the enclosure is secure, but open to airflow ( No glass, plexi, etc. ). It must be secure to keep out potential predators such as birds, canines, cats, rodents, and snakes. Use chicken wire or something similar for the tops and high on the sides. The lower sides of the enclosure can be covered with a finer mesh screen ( 1/4" ) to prevent escapes, lizards getting their head stuck, and things such as snakes getting in; but still allowing migration of insects into the enclosure for the lizards to forage. Fine screen or glass will scatter and weaken much of the sunís UV, hence the reason for chicken wire for the upper sides and top. Landscaping may be required to ensure that flooding does not occur in heavy rain.

For indoor setups using an aquarium, the widely accepted minimum size is 40 gallons. Avoid housing more than 2 lizards in an aquarium smaller than 40 gallons. A 40 gallon is usually best for a pair. Obviously, the larger size tank you can provide, the more comfortable the environment for the lizard. Horned Lizards need adequate space to roam and stimulate natural habits.

Aquarium dťcor often consists of Horned Lizard friendly cacti or other succulents, flat basking rocks or rocks to climb, cave hides for shade and security, and aquarium landscape background scenes. Consideration must be given however to the layout with respect to insects being left in the tank. Crickets will tend to climb and may find a way out, will hide under or behind any rocks or plants, and when left in the tank will often chew up your live plants. Large numbers of harvester ants may damage plants as wellÖsince they are ďharvester antsĒ. A locking aquarium screen hood is a good idea to keep things in, and keep things like cats and dogs-out.

Substrate and Substrate Care

Fine-grade sand, such as play-box sand is a popular suitable substrate for these lizards. A 50lb. bag is sufficient to fill a large aquarium or small outdoor terrarium. I prefer to use that which is sterilized for use in play-boxes. Though more expensive, the calcium carbonate based substrates available at many pet stores is also quite suitable. I have also considered recently the possible respiratory effects of factory produced play-box sand, which is pulverized quartz. Fine particulate quartz poses a long term health risk in humans similar to asbestosis, and it is reasonable to assume the same in reptiles may be true. This sand poses little risk to consumers, and risks generally only to factory workers exposed to frequent dust from production. Though the effect on a lizard residing directly in the substrate is not known. For that reason I have begun to advocate possibly pre-washing and draining play-box sand to remove the fine quartz dust. Substrate should be 2-3 inches deep, sufficient for the lizard to burrow for sleep and thermoregulation.

Clean substrate of scat ( waste ) daily. The best way to accomplish this is with a plastic spoon or small sifter. Sand should be sifted through frequently to remove debris, etc., and should be changed every 3 months or sooner.

It should be obvious that any additional chemical additives should not be used in the substrate. New terrariums should be sterilized with either 1:9 bleach water solution or other common disinfectant solution, rinsed completely and allowed to dry. Avoid using anything with additional additives such as fragrance, surfactants, or detergents. This should also be done as routine maintenance when substrate is changed.

The Importance of UV

Horned Lizards are diurnal, which means they are active during the daytime and require UVA and UVB, as do most insectivorous and herbivorous reptiles; such as turtles, tortoises, iguanas, and dragons.

UVA is beneficial to the activity and psychology of the reptile, promoting healthy activity, alertness, and breeding behavior.

UVB is needed for proper growth by promoting vitamin D3 synthesis important in processing calcium and phosphorus. Just as in other animals that require sunshine, including people, the UVB component of sunlight strikes the skin and the body produces vitamin D3 as a result. Vitamin D3 is used to metabolize the calcium and phosphorus into proper bone growth. Without proper UVB levels and calcium/phosphorus ratio ( Ca:P ) in the blood, the UV dependent reptile will eventually suffer severe bone deformities from Metabolic Bone Disease. The reptileís body will begin to rob the bones for calcium to maintain a homeostasis of blood calcium. The best case scenario is that it will grow with deformities or have fragile bones, and the worst case is that it will suffer a slow death from this. The only reptiles which do not require frequent UVB, are nocturnal ( such as nocturnal geckos or snakes ) or rodent eating; such as snakes and monitor lizards, which derive their vitamin D3 needs mostly by digesting the kidneys and livers of their prey.

Natural unfiltered sunlight is the best source of UV. If you can provide it in a proper outdoor setup, it is preferable. If not; a UVA/B light will be required. There are many on the market today, but the best artificial sources of UVA/B come in the form of mercury vapor spot or flood lamps. Fluorescent tubes or coil lamps are better than nothing, but still inferior in the amount of UV they transmit. Many do not produce sufficient levels to meet the reptileís needs, even when fresh out of the box.


The factor for determining the worth of a UVB lamp is not the % of UVB ( i.e. 10% or 10.0 ) unless you know the intensity of the total light transmitted over the spectrum. The factor you are looking for in a good lamp is microwatts of UVB per square centimeter ( cm2 ) in the appropriate spectral range. An average summer day in the southwest US can see UVB in the 200+ microwatt range. Most reptiles bask in the morning or afternoon hours where UVB levels may reach 100 mW/cm2. It is generally accepted that 20 minutes sunlight exposure per day of such UVB is sufficient for the production of vitamin D3 in the reptile. Most fluorescent lights produce 3-13 microwatts brand new. Heat and UVA/B requirements can be better met by using Mercury vapor lamps, most of which produce at least 50+ microwatts.

DO NOT PLACE LIZARD IN AN AQUARIUM OR PLASTIC BOX OUTDOORS-The heat retained by the glass or plastic will quickly overheat and kill the lizard, turning an 80 degree day into 120 degrees inside an enclosure on the hot sand.

If using an outdoor setup: Provide areas where the lizard may bask in direct sunlight, and plenty of areas of shade for the lizard to retreat to during the day, and where the enclosure does not overheat. Remember, this lizard does not stay out in the sun all day. It retreats during mid-day to shade. The lizard will also derive some UV indirectly from reflected UV ( scatter ).

Lighting Setup and Operation

For an indoor setup a basking and UV light source will be necessary on one end, and cooler spot on the opposite end to retreat from the heat. During spring and summer months the lights should be in operation from 9-10 hours a day. Winter light cycles are addressed in the hibernation section. Most UV and basking lights will need to be within 2 ft. of the substrate to provide adequate heat and UV. Adjustments will be necessary to achieve optimal conditions. The best way to do this is by using separate basking and cool side thermometers. A UV meter which can measure the A and B frequencies separately and give measurements in microwatts is also very useful.

Offer your lizard shaded hides or shaded/cooler areas in which to burrow.

Electric powered heat rocks are potentially dangerous to the reptile and should not be used. The reason is that a cold or sick reptile may remain on the rock too long and burn itself.

Temperatures and Humidity

As with other all reptiles, and diurnal reptiles in particular; proper temperatures are critical. Most people understand that reptiles are "cold blooded". What this really means is that reptiles are dependent on their environment to provide heat. They cannot generate it by in taking and burning calories through metabolism the way that mammals do. Therefore to keep organs and the immune system in working order, the reptile requires heat from itís environment. Without proper temperatures the reptile will not be active, and may show no interest in eating. If it does eat, itís digestive and immune system may not operate properly, causing health problems and making it more prone to illness.

Ambient & Day Temps:
Basking side: low 100ís ( no more than 110í ). I prefer to keep warm side temps around 105. It may reach 115 or so directly below the basking source, which is fine if the setup allows enough of a gradient to be established throughout the habitat.

Cool side: 80ís to low 90ís.

Temps. will be higher directly under the basking heat source, therefore, average ambient temperature should be gauged at the substrate surface away from the center of the heat cone.
These lizards burrow in sand to thermo-regulate and sleep. Often if it is particularly hot, they may burrow in a shaded area or under a cave hide. The mouth being held agape is a sign that this lizard is too hot. Remove it or provide a cooler environment right away!

Night Temps:
Can fall to ambient room or outside temps. without need for night-time heat or lighting, so long as you do not live in a refrigerator and should obviously not get to freezing. If you live in a northern or colder climate than where these lizards inhabit, then an under tank or night heat element might be required. I recommend keeping it above 50*F at the substrate surface. At prolonged low temps. the lizard will go into hibernation.

Humidity for these lizards is less important, and does not require a gauge to monitor constantly. The twice weekly misting with water of the lizard and his surroundings will provide adequate humidity and hydration. Some species or individuals may benefit from a humidity of about 20-40%, especially during shedding. Excessively humid conditions however may pose respiratory infection risks for species that are native to strictly desert environments.


Most Horned Lizards will not drink directly from a dish. I have mainly used dishes as a basking pool. Horned Lizards usually drink by "rain harvesting". As water droplets fall on itís back, water is carried to itís mouth by numerous channels along itís body through capillary action. You may notice the lizard "smacking" itís mouth. This is how it most often drinks.

Some Horned Lizards may drink after being placed in a shallow bath. I sometimes do this to offer additional hydration. Though mine do not often drink this way, some will. As they stand in the water, it will begin to move up their limbs and along their back to their mouth. They may begin to rain harvest and smack their mouths. However, I have found the best way to offer water to a Horned Lizard, is by misting itís back and enclosure with a spray bottle, and the general area around the lizard. It may sometimes lap water off rocks and other items in itís enclosure as well.

Some Horned Lizards may also respond to a dropper, and an alternate method of offering water is to place a drop of water on itís snout, right on the nostrils. The lizard will soon take the water in from itís nostrils and drink. The lizard is able to close the opening to the trachea, at the bottom of itís mouth. This is generally more effective with captive bred lizards, as wild caught Horned Lizards may tend to be spooked.

Most Horned Lizards are native to desert or semi-arid climates, therefore, they do not require constant water, though access to a water source may be helpful. Horned Lizards will generally accept water no more than once or twice a week. Individual characteristics will vary, but I have never seen a Horned Lizard which will drink everyday. If the lizard does not wish to drink, it will probably scurry off.

Ensure the water is close to room temp. Water that is too cold could be a shock to the lizardís body temp. Offer only bottled/filtered, water. Tap water and most "mineral" waters contain "hard" minerals/salts, which may upset the Horned Lizards electrolyte balance.


Insectivorous: The main dietary component for most Horned Lizards is the "Western" or "Red" Harvester Ant ( Pogonomrymex genus ), making up 60%-90% of the diet. The Regal Horned Lizard ( P. solare ) and Desert Horned Lizard ( P. platyrhinos ) are very dependent on Harvester Ants in their diet. Harvester Ant venom contains formic acid and other proteins, which provides proper gastrointestinal pH. This acidity promotes proper gastrointestinal flora and protects the lizard from GI tract illnesses, bacterial infection, and is believed to help fight intestinal parasites ( Dr. Richard Montanucci -Herpetologist ). The Horned Lizard also receives hydration from the chemical breakdown of Harvester Ant venom in itís stomach, which produces a small amount of water as a by-product. Formic acid is also a carboxylic acid, a simple source of building blocks for essential fatty acids, which provides the protein and energy the Horned Lizard needs without loading him down with heavy common feeder items ( such as crickets and mealworms ) that are usually high in fat and chitin, and which are relatively more difficult to digest. Horned Lizards can have, on occasion; small/pinhead crickets, mini-mealworms, flightless-fruit flies, and seem to really enjoy a moth or other winged insect every now and then. Though these are secondary or supplement foods and should not be used as a dietary staple.

If offering crickets, mealworms, etc. ensure they are the smallest size possible. Horned Lizards do not possess great jaw strength and are accustomed to small prey they lift by the tongue, such as ants. Additionally, an insect too large for the lizard may create digestive problems and lead to impaction ( digestive system blockage ) that could kill the lizard.

Crickets, mealworms, and many other common insect feeders, contain a high amount of chitin, but worse, are high in fat and sodium content. They should be used in moderation. The Horned Lizardís system is not suitably adapted for these as a frequent meal. Horned Lizards are sensitive enough without introducing new complications in the diet. The extra fat and salt content contained in many other insect feeders requires the organs of the Horned Lizard to work too hard to metabolize. This consumes the lizardís water stores, which is not good for a desert dwelling reptile. Triglyceride fats in these insect feeders must have their molecular bonds broken down in digestion before the individual components can pass through the intestinal walls into the blood where they are then put to use, or recombined to be stored once again as fat. Triglyceride fats are often composed of a high number of carbon bonds, and the more carbon bonds, the more heat required during metabolism to break them. Such metabolic work requires higher ( or longer ) metabolic activity ( heat ) to accomplish, and we already know that reptiles have a lower metabolic activity than mammals, fish, and birds. Think of the lethargy and energy conservation state of the crocodile or snake after a large meal. This is not required of the Horned Lizard when eating ants. The nutritional components are very simple and require little work before being put to use as energy for the lizard. The trade off is that the Horned Lizard must eat a high number of ants to maintain high activity levels, but, it just so happens that the Horned Lizard has a larger stomach in proportion to itís overall size, for just such purposes! In addition, overuse of prey items that are high in fat in the diet requires extra water in the bowels to digest these components properly. Insufficient hydration can lead to impaction, and for the Horned Lizard species which are desert dwelling, water stores are better put to use elsewhere in the body than being used to break down excessively fatty meals.

To reduce the stress of captivity and moving the lizard to a new home, itís natural staple prey is the best to offer to encourage eating. The Harvester ant is much leaner and nutrients more easily metabolized, thereby rendering needed energy to the lizard quickly and efficiently with minimum strain on the organs.

There has also been limited discussion from time to time amongst some Horned Lizard enthusiasts about the possibility of Horned Lizards in the wild eating plant matter. Specifically, one case is cited from a popular book, ďKrŲtenechsenĒ ( Gerrnan-Toad Lizard ) Bertrand Baur & Richard Montanucci (Herpeton Verlag); in which a P. platyrhinos in an outdoor habitat had dined on the fruit of a Deadly Nightshade plant ( Atropa belladonna ) that was meant for a Desert Iguana. This plant has some medicinal uses as a source of atropine, however, can be toxic to people and domestic animals. Some non-domestic animals have been known to feed on the fruit of this plant without ill effect. It has been speculated that this might have been a form of self medication by the lizard. One other Horned Lizard keeper known by the author stated that he frequently offers chopped greens to his Horned Lizards, and they apparently partake of them to some degree. I have not been able to duplicate this as of yet, however, it is of interest and something I continue to attempt from time to time. If one were inclined to try with their own Horned Lizard I would recommend collards, mustard, dandelion, or turnip greens. However, hold out no particular hope of making a leafy green eater out of your Phrynosoma. To date these reports are isolated and anecdotal.
Handling and Offering of Harvester Ants

When offering Harvester Ants place only a few at a time in with the lizard. Too many and they may turn aggressive and attack the lizard. The lizard tends to become stressed when confronted with more than a few ants in an enclosed space as well.

The Horned Lizard is believed to possess some immunity to the venom ( or rather the venom is less effective against them; which can kill small rodents with as few as a dozen stings ), however it is apparent that they do feel some pain from the sting. Harvester Ant venom it seems is more adapted to defend against small seed foraging mammals. Harvester Ants, though slower to agitate and sting than say imported Red Fire Ants ( S. invicta ), nevertheless, possess a potent sting that is classed as one of the most painful in the insect world. This sting is similar to a bee or wasp sting and tends to be felt traveling up the lymphatic system in some cases. In the blood, the venom acts by causing the red cells to swell with excess water and burst ( hemolytic ). The person stung by Harvester Ants will often feel the sensation of wetness near the site of the sting. People prone to anaphylaxis from insect envenomation should use caution when handling these ants.

Keep Harvester Ants hibernated/dormant in the refrigerator until ready for use. This will slow them down and make it easier for the lizard to eat. Place a few in a pile, preferably not directly under the heat source as this may kill them before they awaken, or make them too active too soon for the lizard to get to them. The lizard will approach the awakening ants to feed on them.

You should offer your lizard a few ants, many times a day if possible. Every time you have the chance to walk by the lizardís home, drop a few in. Any ants that have not been eaten at the end of the day should be removed. If the lizard begins to panic and climb the walls when ants are introduced, reduce the number of ants. An adult Horned Lizard should be eating 50 or more ants a day optimally. Some may even eat 100. A juvenile or baby may eat 10-20 per day depending on size. Offer the lizard as many ants as it feels like eating throughout the day, using common sense based on itís individual size and the size of the specific species of Harvester Ants being used.

Additional Notes about Food Items:

In general do not feed your Horned Lizard an insect you are not sure is safe for it. A good rule is to not give it anything that is not present in itís native territory. For example; the ants you may be feeding it from outside in your lawn might not exist where this lizard came from, and may be toxic to it. Not all ants are the same and some actually contain alarm pheromones, which can be poisonous to the lizard. They also may not provide exactly what the Horned Lizard needs. Dr. Montanucci cites a case where he lost several of his hatchling P. hernandesi after feeding them ďlawn antsĒ of the genus Iridomyrmex.

Some people have a tendency to buy these lizards and try to get out cheap by not buying the proper food. Donít try to get out of buying Harvester Ants if you are going to get a Horned Lizard. It wonít be very healthy without them, and you could potentially kill the lizard this way.

Excrement of Bodily Waste
A healthy and properly fed Horned Lizard will defecate everyday when fed a sufficient regular diet of ants. When fed a diet consisting of crickets, mealworms, or other items, the Horned Lizard will often take longer to digest and pass these items, typically up to 2 days.
Horned Lizard scat should be solid and contain very little moisture. A Horned Lizard eating sufficient ants in the diet will often pass scat that may be as long as the lizardís own tail. It will appear surprisingly large given the size of the animal, but this is the nature of having to eat large numbers of ants. Horned Lizard scat will often be followed by crystalline urates, which will appear as a semi-solid yellowish-white substance. This is the way the Horned Lizard eliminates urinal waste through the renal system while still conserving water. Very little water is passed in the process, and the urates quickly dry into a solid mass.

Excessive salt is often additionally eliminated in the Horned Lizard through the nares ( nostrils ). The salt will accumulate around the nares. Periodically this salt accumulation will be removed by the lizard during normal activity, but it is a good practice to check and lightly brush, upward and away, any stubborn accumulations. Excessive and problematic salt accumulation probably points to excessive salt somewhere in the diet, or insufficient hydration.


To encourage proper bone development and prevent MBD, the reptile needs UVB. But it also needs a proper Ca:P ratio to make use of that UVB. Without proper levels of any of these, the other factors are useless. Excessive phosphorus will inhibit the proper use of calcium, however, it is needed for the process, hence the Ca:P ratio. There should be at least as much calcium as phosphorus present, and twice the amount would be better. Reptiles should optimally be given a diet with a Ca:P ratio of 1:1 or better ( 2:1 ).

Insect feeders generally have a poor Ca:P ratio to begin with, and some are worse than others. Therefore, to make up for this, insects are feed a calcium high diet to ďgut loadĒ them, or they are dusted with calcium prior to being eaten. The precise calculation of Ca:P ratio for the lizardís entire diet is not usually practical, but doing a little research into the common Ca:P ratio for a given prey item and simply being aware of this factor is usually sufficient vigilance. The variety of insects the Horned Lizard eats in the wild cannot quite be duplicated in captivity with reliability; therefore, some adjustment in the captive dietary intake is necessary, though as little as possible artificial means is always best.

For mineral needs, "Miner-all" from Sticky Tongue Farms is a recommended product. Mineral supplements containing 1:1, or better, calcium-to-phosphorus should be dusted onto crickets or other non-ant prey to improve their nutritional value. A straight calcium dust may also be used instead. Calcium is the only supplement which should be given with any frequency. There are substrates on the market which are composed of calcium or contain calcium, and while there is no harm from using them, the lizard derives little benefit from them alone. Do not mistake that all the lizardís calcium needs can be met from them.


A reptile vitamin supplement once a week is more than sufficient. Twice monthly is better. A Horned Lizard on a proper diet will have little need for frequent vitamins. Do not follow label instructions which advise vitamin supplements at every, or every other feeding. This is too much. Excessive supplements can result in hypervitaminosis ( poisoning ), just as insufficient vitamins and minerals can create problems. Vitamin D is a fat soluble vitamin and a hormone produced as UVB radiation strikes the skin. The liver and kidney help convert vitamin D to its active hormone form, D3. The major biologic function of vitamin D3 is to maintain normal blood levels of calcium and phosphorus, and aids in the absorption of calcium. If the lizard is getting sufficient UVB however, there will be little need for D3 supplementation. THIS IS NOT AN ALTERNATIVE TO GIVING THE LIZARD PROPER UVB EXPOSURE! The best way to keep a Horned Lizard healthy is to allow itís systems to operate as naturally as possible. Using substitute methods and products, such as "UV drops" ( D3 ) and D3 powder supplements, by-passes the natural operation of the lizardís physiology and can create problems. In cases of inexperience and excessive use, these methods can be deadly to the animal. Vitamin D3 ( Cholecalciferol ) is also used as a poison for rodents by causing hypocalcaemia. Thus, as with anything, overuse can be a bad thing.

Avoid reptile vitamin sprays. The reptile cannot absorb vitamins through itís skin. It may keep the skin looking nice, but these sprays may also interfere with proper thermoregulation and D3 synthesis.

III. General Maintenance & Notes on Behavioral Characteristics


Your Horned Lizard will occasionally shed during the year, depending on itís age and growth rate. A young lizard will typically shed several times a year until grown.

The beginning of the shedding process is usually first noticed around the snout. Once it has begun, the lizard may be less interested in eating until it has shed, though I have noticed that most Horned Lizards do not fast at all during the shedding process, preferring to eat all the way through. It may take 2-3 days for most of the old skin to be removed. Once the skin has become fairly loose and much of it has begun to fall off, you may assist with the process by gently removing that which is loose in more problem areas for the lizard. These may include the toes and upper limbs, the horns, and around the snout and eyes. Let the process go naturally for a few days, after which check the lizard over for any remaining skin. Use care in these delicate areas, but ensure that old skin has been removed to prevent any infection or other complications from developing in between the old and new layers. A soak in some warm water, rub with mineral or olive oil, or a little skin conditioner spray at this time is sometimes helpful. Tweezers come in handy for this process as well. The nostrils will frequently be covered over by the old layer during shedding, and the horns will have a cap or "sheath" like cover which usually has to be removed by the keeper. Take care removing any remaining old skin near the eyelids or nostrils. Horned Lizards will often flinch or squirm vigorously when these areas are touched and a stray utensil can do them harm.

Cleanliness and Prevention

Keep different breeds and new animals separate, at least until they are deemed to be healthy and parasite free. This will lessen the chance migration of certain diseases. It is recommended to disinfect your hands and utensils before coming into contact with animals in separate housing, especially those of different species. I prefer to use an antibacterial hand gel or soap.

In the case of any minor wounds, contact lens grade saline mixed 50/50 with betadine ( povidone iodine ), may be used for irrigation and wound disinfection. An over the counter triple antibiotic cream every few days may also be required after wound rinsing. In the case of lingering or deep wounds, the lizard may require an systemic antibiotic, such as Baytril ( enrofloxacin ), from a reptile vet.

Horned Lizards frequently may get the substrate sand in their eyes. The Horned Lizard has a method to remove debris from itís eyes by puffing up itĎs eyelids, however, it is not always successful. If needed, sand can be flushed from itís eyes using an over the counter saline eye wash ( sterile-no additives ). In some instances the eyes may be too irritated and the lizard will not keep itís eyes open, or will close them when you are attempting. One method that has worked to open the eyes is to give the base of itís tail a light and repeated squeeze. An assistant is helpful in these cases.


Horned Lizards frequently like to attempt to climb the walls when they are stressed or new to an environment. While doing so they often stand on their tails, which can damage the vertebrae and break their tail. Their tails do not regenerate. Attempt to prevent this with a new lizard by covering the sides of the aquarium with printed landscape scenes. There is less chance the lizard will do this if it cannot see through the glass.

Horned Lizards do not like to be handled, they merely tolerate it, but it is stressful for them. You may notice them orienting their horns on their head in such a way as to protect themselves when touched. Many people think it is cute to rub their heads and watch them close their eyes and duck the head. Like a dog enjoying a petting. But this is actually not the case. This is a defensive posture against a perceived predator. Horned Lizards also frequently puff themselves up by inflating their lungs when they are scared. They do this to make themselves harder for a predator to swallow. In addition, some species can, and sometimes do, squirt streams of blood from the vessels around their eyelids. This is another defense, though it is a rare display toward humans.

Horned Lizards also stress out over frequent traffic, noises, or an audience to close to their enclosure, especially during feeding. Many will not eat if watched too closely.

Avoid housing more males in ratio to females. Excessive numbers of males will harass and highly stress the females, possibly contributing to their death. 1 male for every 2 or more females in a large enclosure would be most appropriate. If housing a male/female pair together, monitor closely the interaction. If the male is frequently chasing or otherwise harassing the female, or she seems inactive, stressed, or will not eat; remove her immediately to her own permanent separate quarters. It is best to introduce females into a habitat where a male has resided for some time and is established in his home.

Visual Displays

Head Bobbing Ė You may notice, particularly with a Horned Lizard fresh from the wild, or with more than one Horned Lizard, a quick up and down motion of the head. This head bobbing is a form of communication. It is observed sometimes during basking or other relaxed activity, but most often it is seen during feeding. It is also frequently seen when Horned Lizards approach or see each other, or particularly when a male sees a female. The Horned Lizard is either looking for a reply to his bob, to see if others are there, or it is communicating directly to the other, perhaps to ascertain species or other information. Each species has itís own particular variation of the head bob. What this communication is exactly about is unclear. The communication may be used as a territorial signal for other Horned Lizards to go somewhere else, especially during feeding. Although some observances of aggression toward different species have been recorded, Horned Lizards are not generally known to be aggressive to one another.

Tail Wagging Ė This is sometimes observed when feeding on ants, but in my experience is most often observed when eating crickets, moths, mealworms or other less frequent prey. It is considered to be a sign that the lizard is excited by the prey, and a healthy sign of how the lizard feels in itís environment. Tail wagging is seen just before the Horned Lizard strikes for itís prey, and may or may not be accompanied afterward by a bob of the head.

Upturned Tail Ė This is often a sign of an agitated Horned Lizard that wishes to be left alone. It is also often seen when a female Horned Lizard is receptive to a male and wishes to mate. It also may be seen when a female is startled and is possibly displaying that she is female, so as to avoid aggression directed toward her.

Tongue Flicking or Licking Ė Like snakes, lizards have a vomeronasal or ďJacobsonísĒ organ at the roof of their mouth which is used to smell with by sampling with the tongue. In many lizards, such as the Horned Lizard, this organ has a reduced functionality. Species of lizard which have forked tongues, similar to snakes, have more sensitivity to scent molecules in the air and make more use of this organ, yet the Horned Lizard can still smell by direct sampling. It makes use of this by frequently licking the rocks, sand, and even other animals around it to sample for scent molecules. The forked tongue reptile has many advantages by detecting scents from long range on the air. This may come into use in detecting females for mating, the scent of another maleís territory, finding water, detecting predators, or tracking prey. The Horned Lizard may still be able to utilize some of this information by sampling by direct contact with the tongue.

Burrowing Ė The Horned Lizard burrows to hide from predators during sleep and to stay warm at night, since it loses heat much slower on cold nights when buried rather than exposed to the air.

Color change-- The Horned Lizard, like many other lizards, uses color changing pigment cells in itís skin to lighten or darken itís coloration. This is commonly seen when the lizard is initially basking in the morning when it is cold, and attempting to maximize heat absorption. As it heats up, it will lighten itís coloration to thermoregulate. Skin darkening ( or ďblackeningĒ ) is also seen when the lizard is sick, or in fight or flight mode, and is stressed. In a lizard that is ill, the skin darkening serves the same purpose as the fever in the mammal. Since the reptile cannot generate itís own heat from muscle ďshiverĒ the way that mammals can, it relies on taking in extra heat from the environment to boost itís temperature. In the ďfight or flightĒ mode, when the lizard is stressed, it will darken itís skin. Though I have not yet read this anywhere, I logically presume the purpose is to boost itís temperature, blood pressure, and circulation, in order to maximize itís response, be it flight, blood squirting or other defense.

ďPeek-a-booĒ -- This refers to the act the Horned Lizard usually takes in the morning as it first awakes and is preparing to get up. What it is doing with itís head poking out of the sand, is allowing the blood flowing through itís head to heat and warm up the brain, as it surveys the area for threats, etc. In this manner it can see what is around it, while minimizing itís exposure. The Horned Lizard has the ability to regulate the blood flowing in and out of itís head to the body, and in so doing, can warm itís blood and brain more rapidly. Once this happens, it can begin to shunt some of this blood to the body to warm itís limbs for movement.

Dominance or possessive displays with the feet -- Many lizards use the placement of a foot onto another lizard to indicate dominance or possessiveness over a mate. Though this is usually seen in larger Iguanas, this has been observed in Horned Lizards as well by the author.

Aggressive displays -- Though more rare in Phrynosoma, occasionally a Horned Lizard may display aggression toward another. A case of a Horned Lizard biting a rival on the tail and limbs, and proceeding to drag it some distance has been documented previously. I have observed similar behavior on two separate occasions from an individual Horned Lizard ( a juvenile female P. cornutum ). In one case the lizard became agitated than an elder female had repeatedly taken her mealworms from directly under her snout, and she abruptly approached the older lizard, dropped her head as a bull, and delivered the larger lizard a swift head butt. On another occasion the larger female accidentally repeatedly stepped upon the juvenile who was partially burrowed in sand. The juvenile abruptly emerged from the sand to again strike the elder Horned Lizard in the same fashion. It should be noted that this particular P. cornutum had a disposition that made this behavior less of a surprise than perhaps it should have been otherwise. She remains the only example the author has seen to actually deliver a squirt of blood upon being picked up by a human. Though being fully capable of this, and the author has seen many blood squirting ĒthreatsĒ ( with swelling of the eyelids ), Horned Lizards do not typically display this behavior toward people unless extremely agitated or surprised.

Signs of Illness

Horned Lizards, like most reptiles, can die seemingly quickly without apparent notice of symptoms, or soon after symptoms are discovered. The reason is that reptiles attempt to hide symptoms of their illnesses as long as possible in the wild, so as not to be singled out by a predator for being weak and easy prey. Many times when the less experienced reptile keeper notices a problem, it can already be too late. Thus prevention and proper husbandry with reptiles is key, as well as not wasting time when illness is suspected. A visit to a competent reptile vet as soon as possible is the best course. Many times a year I answer questions on various forums related to a sick reptile, where someone is seeking "urgent help!", "lizard dying!", etc. What people need to understand is that while many of us on forums can offer good advice and probably diagnose the possible problem(s) with enough information; those seeking such help are not often versed enough in reptiles to give accurate and complete details, and such correspondence is unnecessarily time consuming. This wastes vital time for the dying animal who should be on the way to the vet instead. The forum can be used to seek second opinions and avenues to look into after the animal is in vet care. Additionally one must be on top of their husbandry game with these lizards, as some reptile vets shy from even seeing themÖeither because they are unsure of their legal status as a pet, or because they are not familiar enough with this genus to be comfortable treating them.

A stressed, cold, or sick Horned Lizard may take on a darker coloration. A lizard that is merely stressed will be otherwise alert and active. Remove or reduce factors that could be contributing to stress.

A lizard that is too cold or sick may, in addition to having a dark skin color, also sleep frequently above the substrate, show lethargy, disinterest in eating, and may not open itís eyes. Check temps., and warm if needed. The lizard changes the pigmentation structure in itís skin in these cases to allow it to absorb more heat, thus generating a type of artificial fever, since it cannot generate a fever through muscle shiver the way that mammals do. If itís condition does not improve take it to a competent reptile vet, preferably one who knows Iguanid lizards.

IV. Advanced Husbandry

Common Illnesses & Medical Treatments

Gastroenteritis Infection

A common illness among captive Horned Lizards is gastroenteritis ( intestinal inflammation ) infection, as noted by Dr. Richard Montanucci. ( Montanucci- Maintenance & Propagation of Horned Lizards in Captivity-1989 ). Among captive Horned Lizards he studied with illness, roughly 60% of those illnesses were attributed to gastroenteritis infections of a viral or bacterial nature. Gastroenteritis can commonly be caused or contributed to by prey such as crickets that are filthy or diseased, by parasites such as nematodes attached to the intestinal walls, or by eating of foreign matter that irritates the bowels leading to infection. The author additionally feels that captive stresses on Horned Lizards which may reduce normal immune-response is a significant concern in allowing such infections. Gastroenteritis of a bacterial nature can be effectively treated in Horned Lizards with Tetracycline or other Aminoglycocide antibiotics ( Montanucci-ibid ). Additional hydration support therapy should be performed during administration of such antibiotics, and ideally these antibiotics, if given by injection, should be administered in the front third portion of the reptile so as not to be routed directly to the renal portal system ( kidneys ). Prolonged use of Aminoglycocides may have toxic effects to the kidneys. Outdated Tetracycline is highly toxic to kidneys. Given the time since this article was published other products such as Baytril may need to be evaluated in the Horned Lizard. Baytril and other antibiotics of that class have their own set of adverse side effect concerns, and their overuse in Europe is blamed on resistant enteritis causing bacteria. However, Baytrilís possible damage to tendon, muscle, or motor function seems to be less cause for concern than kidney damage. Gastroenteritis caused by adenovirus infection seems to be increasingly common in reptiles. Symptoms of gastroenteritis commonly include those listed above, as well as;

Elevated upper body posture ( pushed up on itís forelimbs )
Visible labored breathing ( normal breathing is less frequent and subtle )
Watery-unsolid, off colored, or foul smelling feces


A lizard with an impaction may exhibit some of the symptoms described above. This is a serious situation which could result in death if not treated quickly. Impaction is usually caused by ingestion of foreign matter such as rocks or too much substrate, from overfeeding prey other than ants, or from dehydration. Suspected impactions are often treated by the layman with warm water soaks, and while this may help, it most often does not. Immediate supplemental hydration through drinking water and/or saline should also be offered, and the abdomen may be lightly massaged to aid the process. If this does not render results quickly and if the lizard has not passed scat in several days, and has stopped eating, it may require further laxative. The Horned Lizard also does not typically go for as long between meals as do other reptiles. Further treatment for impaction should ideally be performed by a vet, or with the direction of a vet, as if done improperly can give the lizard diarrhea and dehydrate it very quickly, possibly leading to further complications and death. I have had success treating impactions with mineral oil cloacae irrigation or very small ( a few pinhead size ) drops of mineral oil or Milk of Magnesia given orally.


A prolapse occurs when an internal organ is pushed out the vent. The prolapse can be of a sexual organ ( male-hemipenes ) or of the intestines. Prolapses of sexual organs ( hemipenes ) in males is somewhat normal and usually not indicative of a problem so long as there no apparent injury or defecation difficulty that caused it. The lizard usually remedies this situation in his own time.

A prolapse of the digestive organs is less common, but is a serious matter that requires immediate attention to prevent death. If the prolapsed intestine is not corrected soon the organ will dry out, may be punctured, inflamed, or develop infection, and the lizard may not live even if it is put back into place, if the intestine is damaged or prolapsed for too long without treatment. A prolapse can most commonly occur as a result of impaction, from dehydration, or from overfeeding. In this situation the organ should be rinsed with sterile saline or lukewarm/slightly cool clean water. The lizard should be taken to a reptile vet immediately. If this is not possible right away, the lizard should be placed in a lukewarm/slightly cool bath for about half an hour to see if the lizard can correct the matter. An alternative method is to use high amounts of sugar in the bath, or apply a heavy sugar/water paste to the organ very gently with a cotton swab, which may help reduce swelling and ease correcting the matter. If not, repeat frequently until you can get to a vet. Keep the organ covered/protected and moist at all times. Even should the organ be retracted back into the body cavity, the lizard should still see a vet at the earliest possible time. Inexperienced keepers should not attempt to push the organ back in to prevent a fatal damage to the intestine. Replacement of the organ is a delicate procedure.


Occasionally a Horned Lizard may lose interest in eating because of stress or improper food items, or due to illness. In the case where the lizard loses weight to the point that it is dangerously emaciated, force feeding may be required to hydrate and give nutrients while the lizard recovers. There are rescue powder formulations on the market which when mixed with a fluid, provide enough nutrients to the lizard for these purposes. If a reptile is ill enough that it requires force feeding, then it should ideally be taken to a reptile veterinarian. Novices should not attempt to force feed a reptile, particularly the Horned Lizard, which has small jaw part and teeth which may be damaged if done improperly. Any wounds caused by improper forcing of the mouth may lead to additional problems in the form of stomatitis ( mouth rot infection ).

Force feeding of whole insect prey is not advised in the weakened state of the reptile, as it is difficult and may lead to extra stress and trauma. It will also needlessly burden the biology of the reptile by requiring itís digestive system to work more than it should in such a state. The digestion of whole prey in the seriously ill reptile may not take place in itís weakened state, which will not render the nutrients to it, and/or, it may needlessly take water from the other vital organs and immune function and divert it to the bowels, when it is really needed in those other vital organs to fight the illness.

If force feeding I required using liquid formulations, the author recommends the formula be mixed with liquid 50/50 solution of Pedialyte or similar electrolyte replacement, and sterile saline or filtered water. A small ( 1cc or smaller ) syringe and feeding tube ( 5Fr. Gauge or smaller ) lubricated with a light coat of mineral, olive oil, or similar substitute is also necessary. Ensure that insertion of the feeding tube/catheter is not forced, that it does not go farther than necessary down the esophagus, and that you donít accidentally run the tube into the trachea which is the opening at the bottom of the mouth ( on top of the tongue ). The tube must be far enough in to prevent the lizard aspirating and choking on the liquid food, but not so far as to do damage. For these reasons it is recommended this not be attempted by the inexperienced if at all possible.

When it doubt, it must always be assumed that the lizard is possibly dehydrated as well, and fluids should always be part of a force feeding protocol. Even a reptile which is sick, but does not yet require force feeding should be offered constant hydration to ensure optimal biological function. The reptile should be sufficiently hydrated before being fed anything while sick.


In the case of drowning in water, or aspiration of other fluid, the reptile has the ability to survive for some time without oxygen due to itís low metabolic activity. Emergency resuscitation can be performed. Invert the reptile with itís head facing downward to allow any fluid to drain, and pump itís limbs inward and outward from itís body. In the case of lizards, and the Horned Lizard, you may assist the lungs in expelling the fluid and taking in air by gently squeezing the flexible rib cage inward along itís fringe. Oxygen is helpful if available, and if the reptile regains consciousness and begins to breathe on itís own, a nebulizer treatment may be helpful to assist expulsion of remaining fluid. Antibiotic treatment may also be necessary to prevent or treat possible pneumonia that can arise.


Treatment of parasites is covered under the hibernation section.

Reptile safe medications

Medications for systemic infection or analgesia should ideally be administered only by reptile veterinarian or sufficiently experienced keeper, or under the direct consultation with a vet. Dosage calculations and administration protocol for reptiles, especially small reptiles, requires some math and reptile physiology knowledge. Resources Rx Dose
Link Signs of Illness Pain in Herps

Humane Euthanasia

There may come a time during a Horned Lizard keeperís experience where the lizard or another reptile is severely injured or ill, and cannot be saved. In order to spare it from needless suffering, the most compassionate course may be to humanely put it down. It is a hard decision to make sometimes, and a reptile vet should be consulted if at all possible to make the process as painless as possible for the animal.

For many years unenlightened herpetologists, vets, and reptile enthusiasts, advocated stunning, decapitation, or other traumatic brain injury to euthanize reptiles. If not done properly the animal will no doubt suffer more than it has to, and repeated attempts are often necessary. This is not only needlessly traumatic, but generally barbaric practice. It has been reported that the reptile brain remains active for up to an hour after decapitation (Cooper et al, 1984). Overdose by anesthesia is a more humane method, however, as many anesthetics have limited or questionable effectiveness in the low metabolic activity of the reptile, it should not be relied upon entirely. In the authorís opinion the most humane way to end a reptileís suffering is to use anesthetics to render the brain unconscious, in addition to lowering itís body temperature by refrigeration only once the anesthetic has taken effect. When it has sufficiently been under refrigeration to ensure dormancy, it can be moved into freezing temperatures for a time to ensure all biological function has ceased. Some turtle species are resistant to very cold temperatures, even subfreezing temperatures, and in those cases post freezing examination is advised to ensure the animal has indeed expired and will not regain consciousness in pain. When conducted improperly, the formation of ice crystals in the tissue of the animal will be extremely painful. When conducted properly the animal will slip into a hibernation-like state that is not painful , and, simply not wake up.

Hibernation ( Preparation, During, and Post Procedures )

Horned Lizards hibernate in the late fall until late spring/early summer in the wild, like many other reptiles. As with any hibernating reptile, proper fat reserves and hydration to live through hibernation is necessary. As a general rule, if you have not had experience hibernating reptiles before, or it is late in the year and you have recently acquired your lizard; you should not hibernate them the first year. Wait until your second season with them, especially if their weight or other health issues are in question. Sometimes reptiles die in hibernation. In fact, after keeping all sorts of reptiles for many years now, I usually skip hibernation the first year with most of my new reptiles, usually waiting until the second year.

Hibernation is not necessarily a mandatory event with a captive Horned Lizard, however, by offering this natural cycle, your lizard will feel more normal, and consequentially may live a longer and healthier life. When you think "hibernation", many people have images of a bear, sleeping away the winter in a cozy cave den. But hibernation is not a time of cozy sleep. During hibernation, many of the animalís less vital systems are shut down. It is surviving on minimal life support to get it through the wintertime, where it could not survive due to weather conditions and lack of food. It awakens when survivable conditions return. In particular to Horned Lizards; harvester ants hibernate as well
( or more accurately-retreat to underground to live on stored food ). So during the winter months, there are no ants or other insects for the lizard to eat.

Fat Reserves

There are many conditions that must be right in order for the animal to survive this dormant state and come out of it next year. Most important is fat reserves. During hibernation the lizard survives by lowering itís metabolism and burning itís stored fat for food ( fuel ). The lizard must be of healthy weight and have sufficient fat reserves to last through this period. The experienced keeper will be able to tell at a glance whether the lizard has enough fat. The primary indicators of sufficient fat reserves are in the tail and the legs. To prepare the lizard to have enough fat reserves, you may have to increase frequency of feeding a couple of months before you plan to hibernate it.

Clearing the Digestive System

Care should be taken when feeding your Horned Lizard crickets and mealworms. This can set up a fatal problem just before hibernation, one that could kill the lizard if you are not attentive. The same danger from feeding too large or too many crickets and mealworms is present during normal months as well, but during hibernation, even more so. The dangers are from slower digestion of these insects vs. ants, and from impaction. Insects in too many numbers, or that are too large, or which are slower to digest, can create an intestinal blockage or toxemia that can kill the lizard. You must ensure that the lizardís digestive tract is clear before hibernation, as any remaining undigested food items in the lizardís system when it shuts down will decompose and give the lizard toxemia, possibly killing it or making it very ill.

At least a week before you plan for the Horned Lizard to burrow and hibernate, you must discontinue feeding and allow the lizard to digest itís last meal and dispose of it. You should be keeping track of itís bowel movements more closely in the weeks leading into hibernation time, so that you can gauge when itís system is clear. If the lizard is outdoors or in a room where it experiences conditions close to outside temperatures, you may notice it showing a reduced interest in eating as it gets colder. In these cases the lizard usually takes care of this itself. It is still good to keep tabs though, as your lizard is not in the wild, experiencing and doing all things it might be doing if it were in the wild. You have to look at keeping a Horned Lizard in this respect; You are interfering with itís natural wild state, conditions and habits in almost everything you do, no matter how inconsequential it may seem. If you havenít yet verified that the lizardís digestive system is clear before it goes under to hibernate, then wake it up again until it leaves scat again. For this reason you should always remove scat daily so that you can keep track of such things. Besides increasing cleanliness in itís habitat, this helps to pinpoint health issues with the lizard if something goes wrong. If you leave itís habitat dirty with waste, then when it has an impaction, hasnít gone for a few days and is in immediate danger of wonít know about it if you canít tell when it went last.


The next most important factor after fat reserves and clearing the digestive system, is hydration. Increase the amount of times you water your Horned Lizard to 3 or more times a week in the weeks leading up to hibernation. Extra water in the lizardís system will also assist it in clearing the bowels. A dehydrated lizard may wake from hibernation searching for water.


Many insect prey may contain parasites. However, the Harvester Ant is known to be a common carrier of nematodes ( round worms ). Horned Lizards deal with this in the wild; but captive stresses on a Horned Lizard, which can reduce immune system function, can cause an increase of parasitic numbers, and cause complications and illness. Crickets can be particularly filthy if not kept in clean conditions, and this can contribute to disease and illness in reptiles.

There has been much discussion amongst experienced Horned Lizard keepers about the necessity of treating Horned Lizards for parasites. Some advocate less interference with the lizardís physiology and possible pH/electrolyte imbalance. The author views this as a valid concern, however, feels the benefits of such infrequent intrusion ( twice yearly ) outweighs the potential consequences of untreated parasitic infestation.

The Horned Lizard should be treated for parasites with liquid Panacur ( fenbendazole 100mg/Kg ) preferably two months before expected hibernation. The first dose should be followed 2 weeks later by a second, with the last 2 weeks used to give the lizard time to pass any parasites. If you donít know exactly how to do this, see a reptile vet.

Pre-Hibernation Steps Summary

Stock up on fat reserves ( months away )
Treat for parasites ( 2 months away )
Stock up on water ( weeks away )
Clear the system ( week away )

Lighting Cycle

If you are hibernating your Horned Lizard indoors, you can somewhat regulate the time frame of when it goes into hibernation. The way your regulate it is by temperature and lighting. As it nears the late fall, begin to reduce the amount of lighting and heat the lizard gets during the day. If y

06/08/07  04:55am


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  Message To: Phrynosoma_Texas_FS3   In reference to Message Id: 1310412

 Horned Lizard Care Sheet


Lighting Cycle

If you are hibernating your Horned Lizard indoors, you can somewhat regulate the time frame of when it goes into hibernation. The way your regulate it is by temperature and lighting. As it nears the late fall, begin to reduce the amount of lighting and heat the lizard gets during the day. If you normally leave the lights on for 10 hours a day, then start the next week with 9, and 8 the next. You should also move the lights back in increments so that the temperatures are progressively lower during the day as well. I also like to rotate the lamps beam across the aquarium, like the sun traversing the sky. I usually shoot to put them into hibernation just before Thanksgiving, but sometimes the lizard knows best and will go under to hibernate when it feels the time is right. As the Horned Lizardís internal clock gets synchronized with the reducing light and temperatures, it will sense winter coming. Itís metabolism will begin to lower and it may have reduced appetite. If it does not, then you may need to adjust lighting/temps, and offer less food to help reduce itís metabolism further. You will need temperatures to get down consistently to the 60s or a little lower, normally, for hibernation to begin. I attempt to stay within the low 50s during hibernation.

Premature Waking During Hibernation

Once hibernated, the lizard may stay down consistently until spring, or it may awaken a few times. In my experience, when hibernated indoors, they sometimes awaken a couple of times over the winter. Usually itís due to a warm spell, but there are other reasons why they may wake. Among the most common are:

1. Rising temperatures may cause their metabolism to raise and wake them up, especially if their sand is not deep enough to insulate them from warm spells. Ensure that where ever you hibernate your Horned Lizard, it will be fairly immune to warm spells, with an average temperature as consistent as you can get it. Also ensure that it will not become cold enough to freeze. If the lizard is not protected by enough substrate ( from the top and from the bottom of the aquarium ) then it may freeze to death.

2. They may be dehydrated and searching for water. Offer water and see if it drinks and goes back to sleep soon. Water is ok to give at any time.

3. They may be sick or have insufficient fat reserves. It is hard to tell sometimes if a groggy Horned Lizard coming out of hibernation with a low metabolism is actually sick or not. If there is any question about it being ill, then warm it back up slowly and check itís reactions and activity. If it seems well and alert after warming for part of the day, then allow it to cool again and return to hibernation. If there is any question that it might not have enough fat, or it still appears to have something wrong with it; then discontinue hibernation and slowly return itís habitat to warmer temperatures. Seek assistance of a competent reptile vet if normal recovery and activity is not resumed within 2-3 days.

Do not give the lizard food while it is temporarily awake if you plan to return it to hibernation. If you do, then you must wait several days again until you are sure itís system is clear. But keep in mind that the longer it remains awake, the faster it is burning calories and fat. Either put it back into hibernation within a few days, or abort hibernation.

If the lizard is waking excessively during the winter, then abort hibernation.

I tend to prefer my reptiles to awaken at least once, so I can check on them. But you may also have a Horned Lizard which is sleeping much so that you worry that it is still alive. It is not uncommon to have a Horned Lizard go most or all of the winter without seeing it. This is usually a good sign if it was healthy, had enough fat built up, and was hydrated. But sometimes I get the urge to check on them anyway. The best way to do this is to scrape back a little sand from around it, and rub itís head, itís fringe scales on itís side, or lightly squeeze the base of itís tail. Usually it will respond with a slight movement while staying "asleep". Do not dig the lizard up completely nor disturb the sand under itís belly, nor around the limbs. Do not re-bury the lizard. The Horned Lizard has a specific way that it burrows which allows it to sleep under the substrate and still have room for the body cavity to expand for respiration. This involves specific placement of itís forelimbs to itís sides. Let the lizard burrow itself.

Awakening from Hibernation ( Spring )

As spring comes and temperatures begin to get warmer during the day, the Horned Lizard will probably wake on itís own. You may find him/her sitting on itís favorite basking spot one morning waiting for sunshine. If by late April or early May your lizard has not awakened yet, or the lizard is "up" and "down" as we say, then begin to cycle your lights and temperatures back up, in reverse order from how you did in the fall, to simulate approaching summer.

You donít have to take a month getting the lights back to 10-12 hours a day and the temps into the 90-100s, but you donít want the lizard to go from hibernation to summer basking temps by the next day. Anything you can do to reduce shock/stress and make things more "in the wild" normal for the lizard will likely help it live a longer, healthier life.

Proper temperatures are also important to get the metabolism back in order and encourage appetite, and for proper digestion. Most reptiles need warm temperatures for all itís organs to operate properly and digest itís food. Once your Horned Lizard wakes from hibernation and gets warmed up a little it is likely to be thirsty first. Give it plenty of water. This will help get itís organs back to running normally, by flushing any waste and preparing the digestive system for food. Itís probably not going to want to eat a big meal with a dry whistle and bowels. This could also cause an impaction.

After it gets some water for a day or two, then offer it some harvester ants. This is small prey and the breakdown of the venom will help further hydrate it.

On occasion, a reptile will not seem to be hungry after being awake a week or more. If this happens, ensure that your temperatures are correct, and that you are giving it sufficient UVA/B exposure and water. A lack of these can cause loss of appetite. If the problem persists, try another food item to get itís interest. If this is unsuccessful, consult a reptile vet or competent keeper quickly. Horned Lizards do not go as long without food as many reptiles are capable of doing. After the lizard has been awake for a few weeks and is back to normal, eating good and basking plenty, it should be treated again for parasites in two doses / 2 weeks apart.

Post-Hibernation Steps: Summary

Warm up
Offer small prey
Treat for parasites

By following these instructions you should have a good chance of success with hibernating your Horned Lizard or other reptiles.

Horned Lizard references:

Introduction to the Horned Lizards of North America
Wade C. Sherbrooke
California Natural History Guide
ISBN 0-520-22827-8

Horned Lizards
The Book of Horny Toads
Jane Manaster
Texas Tech University Press
ISBN 0-89672-495-6

Lebensweise, Pflege, Zucht
Bertrand Baur and Richard R. Montanucci
ISBN 3-9802892-8-1

For additional information and discussion about Horned Lizards:
Link - authorís profile containing weblink to scientific papers, husbandry tips, & ordering of Harvester Ant feeders.
Link Reptic Zone Horned Lizard Forum
LinkHorned Lizards species information
LinkHorned Lizard Conservation Society
For valuable resources on general reptile husbandry and wellness:

For information about UV lighting: - recommended UV products

06/08/07  08:53am


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  Message To: Phrynosoma_Texas_FS3   In reference to Message Id: 1310482

 Horned Lizard Care Sheet

A few updates were added to this sheet, including links, medical care, and images to aid in sexing. The latest version is available at my website listed in the profile Link

07/20/07  07:10am


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  Message To: Phrynosoma_Texas_FS3   In reference to Message Id: 1310412

 Horned Lizard Care Sheet

I was looking through your diet section of the care sheet, and was wondering how you feed your Horned lizard harvester ants? Like do you special order them, if so can you point me in the direction of getting them (harvester ants). If not then what would you recommend me feeding my horned lizard when aquired. So far all the caresheets i have looked apon, yours is the most helpful


10/08/07  12:45am


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  Message To: Csalazar2285   In reference to Message Id: 1471115

 Horned Lizard Care Sheet

I donít have to order because I actually live where there are both Horned Lizards and harvester ants. I actually sell them myself. If you look under my profile you will my Horned Lizards webgroup. This care sheet has been updated since posted here, and is now known as the Horned Lizard Husbandry Manual. You can get the newest version on my website, as well as other papers of interest about Horned Lizards.

I have classified ads for the ant feeders listed under the classified section. Prices may vary, and it is getting very close to winter, so I wonít have them much longer until next spring.

10/08/07  01:01am


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  Message To: Phrynosoma_Texas_FS3   In reference to Message Id: 1471127

 Horned Lizard Care Sheet

Sorry, my classified ad had expired. I just submitted a new one. But if you PM me your email I can get you set up.

10/10/07  11:36pm


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  Message To: Csalazar2285   In reference to Message Id: 1471115

 Horned Lizard Care Sheet

I get harvester ants for 500 ants are 10d plus like 5d for shipping.

09/01/14  11:58am


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  Message To: Phrynosoma_Texas_FS3   In reference to Message Id: 1310482

 Horned Lizard Care Sheet

Thanks for this article. It has helped me in learning to figure my critter out. I have added it to my favorites link and refer to it when I have questions.

05/26/16  08:06pm

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