Eastern collared lizards (Crotaphytus collaris) are a perfect lizard in many senses of the word. They make an excellent first pet lizard that is easily cared for, handled, and tamed; in fact, they have surprisingly soft skin that feels nice to touch. They are a remarkably colorful lizard with an appealing form, which makes them lovely display lizards in a well crafted naturalistic rocky desert terrarium. They come in many color varieties and locales each with its own unique charms. With proper deliberation and careful design of their terrarium, they also may be kept outdoors year-round in much of the US. Eastern collared lizards are truly an extraordinary species which offers at least one point of interest for all lizard lovers.
We have kept and bred collared lizards in 3 categories of terraria: indoor terraria, outdoors in table-top terraria, and outdoors in our custom raised-bed terraria. Each of these methods is described in this article.
Before examining each type of terrarium we have used, let’s take a moment to talk about the number of animals per terrarium.
If you are considering a collared lizard for a “pet”, a single lizard will be happy and healthy; he or she will do just fine with only you for companionship. In this case, we recommend that you give plenty of attention to your collared lizard on a regular basis through hand feeding, plenty of time outside of the terrarium, and plenty of time spent interacting with you to provide it with a stimulating and interesting life.
Intrinsically Ectothermic is in the business of breeding lizards, so we keep our collared lizards in groups. We have housed 1 male with up to 7 females in our large outdoor terraria, but after trying different group sizes, we feel that 1 male and up to 3 females is optimal for all of our terraria, indoors and out. 1.3 has become our standard ratio for all the terraria described below. For professional breeders, we have found this ratio gives us our best production.
If you are a terrarium hobbyist with a lizard collection, 1.1 or 1.2 is less work and still allows you to observe your lizards enjoying their social and reproductive behaviors. If you have never bred, raised, and sold baby lizards before, 1.1 keeps things simple and is a good way to “test the waters”.
More than 1 adult male should not be kept in the same terrarium, because adult male collared lizards will become territorial and aggressive towards each other and will fight, stress, and kill each other.
Indoors we keep and breed these lizards in 36″ x 18″ x 18″ glass 40 gallon “breeder” terraria, as well as 48″ x 24″ x 18″ Reptile Habitats 90 gallon reptile enclosures.
Our designs for these terraria have ranged from relatively simple setups to elaborate, naturalistic, and bioactive setups.
The simplest of our terraria to date are glass 40 gallon breeder tanks. We continue to use these tanks primarily because we have had several old ones given to us secondhand over the years. These are old top-opening reptile “tanks,” which makes getting into them less than ideal. Top-opening tanks require the constant juggling of lights to feed, water, clean, or examine a lizard. They also invite lizards to jump out when the top is opened and your hands are busy. Front-opening terraria are much better. They are much easier to get into, and the lizards tend to be more calm and relaxed when the doors are opened because things are not being shifted around above them.
Although we have used this size of terrarium for breeding groups consisting of a male and up to 3 females, we also feel this size tank is a good minimum for the long-term care of even a single pet collared lizard; a single collared lizard should not be kept in a smaller terrarium because they are very active. Pet collared lizards kept in this size terrarium are best given regular “out time” for exercise and mental stimulation.
In the simplest of these terraria, a 16″ x 8″ x 8″ cored concrete block is placed long ways on the bare glass terrarium floor, centered near one end of the tank. The solid sides face downwards and upwards. This provides an elevated platform for the lizards to use for basking. The solid face of the concrete block provides a large surface area beneath the lights on which a breeding group can thermoregulate and UVB regulate. The block also provides a surprising amount of visual barriers for lizards who want a little privacy. When sitting near or on the block, lizards may adjust their position to use any of the 3 vertical walls or the large horizontal platform to block other lizards from view if they so desire.
An inch or so of sand is added to cover the rest of the floor. This sand is spot cleaned daily, using a plastic disposable glove to pick up and remove lizard droppings.
During egg-laying season, a 3 gallon Rubbermaid brand Roughneck storage tote is placed front to back on the opposite end of the terrarium from the concrete block. A small access hole is cut in the lid of the tote and the tote is 3/4 filled with slightly damp organic garden soil. This area serves as both a hide and as a nesting box for gravid lizards. The nest box provides additional large visual barriers for lizards, as well as a hiding place inside the box.
Collared lizards are social, and really do not require a lot of privacy from one another in the terrarium, but giving them options to get away from each other in case they feel the need to never hurts. They are usually not shy of each other at all, nor are groups that consist of only one male aggressive amongst themselves.
When females are not displaying breeding coloration, the tote is removed from the terrarium so the lizards have more open floor area to run around on, which they do use.
Our collared lizards have thrived in our simple 40 gallon breeder terraria. We can measure this by their appetite, thermoregulatory and social behaviors, coloration, body condition, posture, and reproductive behavior. Nevertheless, larger terraria are even better. They allow the lizards more room for activity, and allow the owner more room to set up an environment both more interesting for the lizards and more pleasing to the observer.
This year in our larger 90 gallon terraria, we have tried more elaborate, naturalistic, bioactive setups with boulders and a clay soil mix. In both nature as well as in our outdoor terraria, these lizards spend a great deal of time digging and improving their burrows – especially in the spring. They are also able to climb and jump between boulders, which they enjoy. Our indoor bioactive terraria allow them to replicate both of these natural behaviors within our reptile building.
We arrange the rock structures which will serve as basking and climbing surfaces prior to adding any substrate. Stones need to be safely placed prior to substrate being added so that burrowing lizards have no risk of being crushed. Flat-bottomed stones are placed directly on the floor of the terrarium. Stones that do not have flat bottoms may shift when a lizard burrows. To prevent this, we set each large stone on a pair of bricks to stabilize them. The weight of the stones and the bricks themselves make it impossible for the collared lizards to move them. This also slightly elevates the stones, bringing their basking surfaces closer to the lights. The area beneath the stones and between the bricks is also a favorite for collared lizards when they make burrows, as they like to make their burrow homes beneath large rocks.
Once the stones are in place, substrate can be added.
The substrate is made from clay soil found in our yard here in Virginia mixed with paver sand. The ratio is 3 parts sand to 5 parts clay soil. Because the clay soil is dug from our yard, it already contains tiny organisms that make it bioactive; tiny insects feed on lizard waste in the terraria, making cleanup minimal. We also add isopods collected from our yard to the substrate to aid in the breakdown of lizard waste. They live and reproduce well in the terraria, being somewhat native to the substrate and finding enough humidity by burrowing into the substrate and spending daytime hours beneath the large stones, etc.
This bioactive substrate is lightly sprayed every day or two to keep the organisms alive, and to keep it soft enough for burrowing. When dry, although the burrows remain, the substrate becomes hard. Enough water should be added so that the surface dries out after a short time, but so that below the surface, the substrate remains humid and easy for the lizards to dig into for their burrows. Slightly damp and humid underneath, but dry on the surface should be the goal rather than completely dried through or moist.
Succulents may be planted directly in the substrate. One note of caution – some succulents are nibbled on by the collared lizards. One of our plants soon had no leaves. We don’t know which plants may be toxic to these lizards.
From a pet owner’s point of view, this sort of bioactive terrarium is very rewarding. Collared lizards spend a significant amount of time constructing and improving burrows and this setup allows them to express this behavior. This is very entertaining for the owner. The bioactivity simplifies clean up. Observing the lizards expressing their natural behaviors in a naturalistic setup is both captivating and pleasing in a way that is difficult to describe.
These setups do have downsides as well, however. The moisture content of the substrate must be maintained through spraying every day or two. The lizards’ continual burrowing efforts will eventually terraform their environment, so the substrate must be manually reformed around the rocks every few months. The largest drawback for professional breeders like us is the difficulty with collecting their eggs. We find these lizards prefer to create nests around and beneath the rockwork. Our larger stones weigh 30 to 50 pounds, possibly more. In a front opening terrarium with restricted height of only 18″, lifting these stones carefully out of the terrarium to collect eggs can be difficult. Removing the stones requires removing all of the substrate directly surrounding them. The whole process of excavating stones, lifting them out of the terrarium, digging for eggs, replacing the stones, and finally reforming the substrate around the stones takes a significant amount of time. After the eggs are retrieved, everything must be put back in place. This would not be too much for a hobbyist with a small collection, or a pet owner with a single terrarium, but can quickly become unmanageable for a collection of many terraria. For us, each terrarium has multiple females, which means that during laying season this must be done 2 to 3 times a week per terrarium in order to retrieve all of the eggs. This can take a surprising number of hours throughout the week, making this setup impractical for our situation.
Next year, we will have a compromise between simple and naturalistic in these indoor terraria. We will set our stones up using bricks where necessary like last year, but we will use a simple sand substrate roughly an inch thick alongside nest boxes to make egg collection reliable, time efficient, and practical. This layout will still create some “caves” for the lizards to explore, and will still let them climb and jump between boulders. This compromise still gives something of a natural look, and provides an interesting terrarium for the lizards to explore. Cleanup is more time-consuming, but is easily manageable if done daily when feeding and changing water.
If this was in our living room and we only had a single or pair of collared lizards, the naturalistic bioactive setup would be our setup of choice – it looks attractive and the lizards are captivating to observe in such a setup. During the breeding season, looking for eggs only every few weeks for a single pair in a naturalistic setup would be manageable.
In both setups, two ceramic cat food bowls with flat bottoms and straight sides are placed on the floor of the terrarium; these bowls are used to hold food and water. During the egg-laying season, if a nesting box is used, these bowls are placed on the lid of the box to encourage the lizards to find the entrance.
We have used a couple of other terrarium setups indoors in the past. Both of these involved terraria that were 3′ x 2′ x 2′.
The first terrarium setup was a plywood home-made terrarium with a glass front, used to breed a pair of collared lizards in the late 1990s. This terrarium was built pragmatically, but worked well. The extra space allowed for a more naturalistic display with large stones and more room for the lizards to climb and jump.
The second terrarium setup was an all-screen enclosure that was moved outdoors during the summer and indoors for breeding during the winter. This terrarium ended up using too much power to keep warm indoors because of excessive ventilation.
Collared lizards who are bred indoors early in the year can later be moved into much larger tabletop terraria during the summer months, enriching their lives with interesting sights, sounds, and smells. This also allows them to bask in real sunshine, much more beneficial than any UV lights on the market today, and saves the owner electricity and bulb replacement costs.
In the room where our indoor terraria are located, temperatures often drop as low as 68 to 73F at night and rise to nearly 80F during the day.
In our simple 40 gallon terraria, we place a large clamp-light dome reflector over the end of the terrarium, set above one end of the concrete block. We place a UVB tube fixture across the center, also over the block.
In the dome reflector, we use a 100-watt incandescent light bulb. The placement of the light over the block below provides a surface basking temperature of roughly 115F at the warmest point of the block face, directly beneath the brightest portion of the heat light. This temperature could be lessened by several degrees; when we measure the body temperature of our collared lizards, indoors and out, in shade or in full sun, or under basking lights, they seem to prefer a body temperature of roughly 102 to 103F during the day. Studies have shown that sick lizards will sometimes give themselves a “fever,” basking at an elevated temperature. We have also noticed that lizards who have recently eaten a lot will often do so as well. As such, we like to provide a basking site that is at least a few degrees warmer than their preferred body temperature. That means that anything less than 100F will not be very effective in helping your lizard achieve its desired body temperature, and anything more than 110F is really a bit more than it needs.
Collared lizards can deal with surface temperatures in excess of 130F if they have a true thermogradient setup, rather than a simple “hot spot” so that they are in control of their body temperature. They will not utilize such hot temperatures for very long when available, instead usually selecting a basking location slightly off to one side of the hottest spot.
Through observation of our lizards, we determined that in our 40 gallon tanks in a 74F room, we needed to provide an additional 40-watt heat lamp over the “cool end” of the enclosure to raise the ambient temperature into the low 80s in the cooler parts of the terrarium. Before adding this second lamp, the lizards tended to be darker and drabber in coloration and did not actively explore the terrarium beyond the concrete block face near the primary heat source, and that was our clue that we needed to raise the ambient temperature over the cool end by providing a second lamp. This did not need to be very powerful to make a big difference, but if the lizard behavior had not changed after providing the 40-watt lamp, we would have increased the wattage until the lizards looked and behaved normally.
In our 90-gallon terraria, we provide two 100-watt basking sites, one on each end of the terrarium. One site is a little warmer than the other, which is accomplished by differentiating the heights of the two basking spots. The higher elevation basking surface, being located closer to the bulb, serves as the primary basking area. The lower elevation basking surface on the other end of the terrarium serves as the secondary basking area. The approximate temperature at the primary site sits around 110 to 115F, while the secondary site sits around 100 to 105F. Similar to with the 40 gallon terraria, a third site was found to be necessary to raise ambient temperatures and provide a little more light. This tertiary site, located adjacent to the primary site, is warmed by a 40-watt bulb. These 3 bulbs, along with the variable elevation of surfaces in the terraria, create true thermal gradients within these terraria. The cooler portions at the lowest elevations remain about 78 degrees. A UVB tube is provided adjacent to the basking sites.
Because lizards understand how to utilize the true thermogradient we have set up in our terraria, we do not need to force the temperatures to be exactly one fixed temperature each day with a thermostat. Such a constant situation is unnatural. Temperatures in the room can safely rise or fall 10 or more degrees from normal during the day and the lizards will still safely maintain their usual body temperature of roughly 103F. Even though the warmest and coolest temperatures within the gradient may fluctuate and change along with the ambient room temperature during the year, the thermogradient we have set up for them allows them to accommodate for such fluctuations and maintain their desired body temperature.
No heat or light is needed or desirable for these lizards at night indoors, unless for some reason night temperature in your home drops below 50F. The cool and dark conditions allow the lizards’ metabolisms to slow, and allow the lizards to rest peacefully.
Please Read! Keeping lizards outdoors is a little more advanced/risky than keeping them in indoor terraria. Outdoors, there are sometimes extreme weather conditions, predators, as well as the risk of escape into the surrounding environment.
If you live in an area where environmental conditions might allow terrarium escapees to survive and reproduce, please take all precautions necessary to ensure this never happens.
Laws have already been passed in some states prohibiting the keeping of certain lizard species that have been able to escape, survive, and reproduce in those states. Responsible husbandry that prevents escape helps ensure the future of the hobby for everyone, indoors and out.
Monitor your terraria and inhabitants carefully every time they are exposed to a new weather extreme until you are certain that your terraria can handle the extreme conditions in your area for heat, cold, wind, rain, snow, etc. safely for your lizards.
This article shares our methods which are safe for our lizards in our situation. Your situation will likely be different and a certain amount of tweaking will likely be necessary on your part to provide safe conditions for your lizards. Sharing what we do is not the same as instructing you to do the same.
We are not responsible for any harm that you may cause your lizards if you try to reproduce our success here!
Outdoor terraria provide lizards with real sunshine, changes in weather, and fresh air, as well as outdoor sights, sounds, and smells to enrich their lives in a way that even the most elaborate indoor terraria cannot.
Outdoor terraria are normally much cheaper to set up and maintain than indoor terraria. There are no expensive light fixtures and UVB lights, and no electricity costs. For the same amount of money, you can buy or build an outdoor terrarium that is several times larger for your lizards than an indoor one.
No indoor lighting works the same as real sunlight with lizards. For many species, you can see it in the coloration of the lizard after being outdoors full time for a month or two. The color of our “Turquoise Blue” collared lizards absolutely glows after they have been exposed to sunlight for several weeks.
Real sunlight is different than artificial lighting in other ways as well; our collared lizards can utilize solar radiation to build and store heat like little bricks in the sunshine. Even early in the spring on days when ambient outdoor temperatures are only in the low 50s, the lizards are able to achieve their desired 103F body temperature in our raised bed terraria. On these days, the lizards are often warmer than the stones and sand they bask upon.
Compared to lizards who live in our other terraria, hibernation is very simple for lizards that live full time outdoors in our raised bed terraria. These lizards will prep themselves and burrow in on their own until springtime when it is appropriate for them to come out again and start breeding.
It is also healthy for humans to get sunshine and spend time outdoors in the sights, sounds, and smells of nature. There is something incredibly special about going out into the garden and observing the lizards in the terraria there. Until you experience it for yourself, it is difficult to imagine how satisfying and pleasurable it truly is.
When considering winter weather conditions, the USDA zone map is a useful reference. We are located in Central Virginia in USDA zone 7a. A quick check of the USDA map shows that most of the Eastern Collared Lizard’s natural range is similarly zoned.
Summer weather here lasts about 5 months. During those months, most days are in the upper 80s, while most nights are in the mid 60s. Most years we have days here and there in the 90s, and several days each year tend to be in the upper 90s. Near the beginning and end of the summer season, we have days in the 60s and 70s, with nights in the low 50s. Most weeks it rains at some point, though sometimes we go two or three weeks without. When it rains, it can be a passing thunderstorm, especially earlier in the season in the afternoons. Occasionally, it can be cool and cloudy with rain showers for 3 or 4 days at a stretch.
We had collared lizards in our outdoor terraria on the coolest, wettest year on record here. That year, it rained nearly every day from late winter through early fall. Temperatures remained cool as a result, with most days in the upper 70s to low 80s. We did not get much breeding from the collared lizards that year, but they remained in good physical condition (good body weight and otherwise healthy) despite the bad weather.
Sometimes, we have a summer with several weeks in the 90s and many days in the upper 90s, but those have been rare, exceptional years. Our collared lizards have done fine during those exceptionally hot summers.
Our winters here tend to be fairly mild. Most days are above freezing in the low 40s to low 50s, although we can occasionally go for several days below freezing in late December through January. Most night temperatures are in the mid-20s to mid-30s. We sporadically get nights in the teens, with a very few exceptionally cold nights in the single digits every year. When it snows, most years the snow is gone within a day or two, but sometimes it lasts a few days longer. Sometimes, the wind can be quite strong and very cold. On some of our colder nights, it is well below zero with the wind chill factor. In these weather conditions, our collared lizards overwinter well as they hibernate below ground in our raised bed terraria covered with protective tarps.
We call these our “Tabletop Terraria” because we keep them on low rustic tables made of 2x4s. These tables are about 18″ off the ground. This is high enough that wild animals do not bother them. Decades ago, we had initially started with our terraria on the ground. The first year, a raccoon broke into one of these terraria, promptly devouring the poor Chamaeleo dilepis hatchlings who called that particular terrarium home. Subsequently, the racoon left a pile of its own droppings inside the terrarium as thanks before fleeing the scene of the crime. After “the raccoon incident,” we started using the tables and have never had a break-in from a wild animal since. On our property, we have seen raccoons, opossums, stray cats and dogs, skunks, coyotes, foxes, and even a bobcat and a black bear. Since moving the screen enclosures to tables, none of these have bothered our lizards. Sometimes we have even seen them walking between rows of terraria.
Our Tabletop terraria are used seasonally when weather is warm enough for the lizards. We bring our collared lizards out to live in them in the late spring when night temperatures raise to above 50F, and the lizards remain out on the tables through summer, until fall temperatures decrease to below 50F at night. Here in Central Virginia, this allows us to keep our collared lizards outdoors about 5 months of the year, some years up to a month longer.
The collared lizards in these terraria usually stop feeding sometime during their last month outdoors as they feel the change in weather and begin preparing themselves for hibernation. They are brought indoors to hibernate for the winter until the spring; when weather becomes appropriate, they are returned to their outdoor terraria where they will breed during the summer.
We have also taken some groups of collared lizards from these terraria, brought them indoors for cooling at the end of the summer, and then woken them up to breed indoors in the early part of the year. After the indoor breeding season had ended, the lizards were returned to their outdoor terraria for the summer months to relax and fatten up for the next year.
One year, we used the same tabletop terraria indoors with the collared lizards, but heating them required more powerful lighting and larger power bills than the glass terraria. So we prefer a separate indoor terrarium/outdoor terrarium when using this indoor/outdoor husbandry method.
Our outdoor tabletop terraria are made of aluminum window screening and framing. Some of them are homemade, some are commercially made. Although the commercially made terraria are a little more expensive, we eventually decided the slightly higher cost was worth it because the terraria are sturdier and the doors close snugly so that even baby insects cannot get out. They are also much faster to assemble, and splining the frames of the homemade ones can be an exercise in frustration.
Our tabletop collared lizard terraria measure 3′ x 2′ x 2′. The cost of this size window screen terrarium is less than the cost of a 40-gallon breeder glass terrarium.
We cut a piece of fiberglass reinforced wall panel to cover the screen on the bottom of the terrarium. This creates a solid bottom which gives more support for objects placed in the terrarium, and allows for the lizards to scratch against it when digging, rather than against the screen.
On this panel, we place 2 bricks about 12″ apart. These bricks will hold the weight of the heavy blocks above them, so it is important that the table is constructed to support the weight of the bricks below the bottom of the terrarium. The screen side, even with the panel, will not be strong enough without support beneath. To provide this support, we use a couple of 2x4s running front to back on the table frame, placed directly below the location of the bricks. These bricks will be the walls of our “cave” the lizards can burrow into and use for sleeping, thermoregulation, and hiding. On top of the bricks, we place a large square patio block. This forms the roof of the cave as well as our first basking platform for thermoregulation. On top of the patio block is placed a cored concrete block, flat side up. This provides an elevated position for basking and observing the area around the terrarium.
Next, we cover the entire bottom of the terrarium except for the area between the bricks with enough Dumor brand chopped hay to reach the patio block. This hay is very clean and dry, edible, absorbent, and can be spot cleaned quickly, making it a nice substrate for desert lizards on our tabletops. A few inches will last all summer with regular spot cleaning. It is also an insulator, so it helps with thermoregulation. The lizards can burrow into it to cool down on hot days or to slow heat loss on cold nights.
Although the hay works excellently, it does have a couple of downsides.
The first downside is that the hay must be kept dry. If it gets rained on, it quickly becomes moldy. We prevent this by covering our tabletop terraria with tarps when rain is forecast
The second downside is that chopped hay does not look very natural. Neither do concrete blocks. You could create some sort of substrate holding pan for the bottom of your terrarium instead and use a heavy-duty tabletop below and use sand/earth/stones/branches, and that would be fantastic. But this article outlines what we have done. Take our ideas and modify them to suit your own tastes to meet the needs of the lizards in your own situation.
Our terraria are oriented the long way from east to west. Our block stack is near the center of each terrarium, slightly to the west side. Immediately adjacent to the block stack in the northeast corner of each terrarium is a 3 gallon Roughneck Rubbermaid storage tub, set up and used as a nest box in the same way as our indoor terraria. Above this nest box is a solar shield of some sort to shade the box. Anything can be used; we often use white lids for 20 gallon plastic storage tubs. The location in the northeast corner provides shade for the block stack as well, as the sun moves lower on the western horizon in the afternoon. The solar shield is tied down with string so it doesn’t blow away when there is wind.
On top of the nest box, we place a cat bowl filled with water and next to it, on the patio block between the cored concrete block and the nest box, we place the food bowl so the insects also have shade.
We designed our naturalistic “raised-bed terraria” to be used outdoors year-round here in central Virginia. During the winter here, in zone 7a, it never freezes deep in the earth in these terraria where the lizards hibernate.
For lizard keepers, our raised-bed terraria are the most satisfying of our terraria. They provide the most space, and allow the lizards to behave most naturally; the lizards bask on rocks, jump, run, spend a lot of time digging and improving their burrows, etc.
For lizard breeders, these outdoor terraria offer both advantages and frustrations.
One significant advantage for the owner is cost. There are no lighting fixtures, electricity costs, or expensive tubes or bulbs to regularly replace. Construction costs are very affordable. These terraria cost about the same as a 40 gallon breeder terrarium, perhaps a bit cheaper when indoor lighting is accounted for. For a space comparison, our indoor glass terraria have a footprint of 36″ x 18″. Our raised-bed terraria have a footprint of 6′ x 3′. Our glass terraria indoors are 18″ high; our raised bed terraria outdoors are 36″ at their highest point from the surface of the surrounding earth, and extend another 12″ below the surface of the earth at their shallowest depth.
Ease of husbandry is another advantage. We do not have to clean up after the lizards, except to keep the water clean. These are bioactive enclosures. We helped things along by seeding the terraria with a few isopods that we collected in the yard.
Another advantage for the breeder is the ease with which collared lizards slow down, hibernate, and cycle for breeding. Nothing special on the part of the breeder needs to be done other than allowing the lizards to follow their natural cycle. The lizards determine for themselves when it is time to stop eating and fast, when to dig in and rest for the winter, and when to re-emerge and begin breeding in the springtime.
The primary frustration for the breeder is finding collared lizard eggs when they nest. We are currently trying to work out a method to make one area more appealing than the rest of the terrarium for females to nest in, without a lot of progress yet for collared lizards. Until such a method is figured out, over time the owner can learn to become familiar with where females prefer to lay.
These terraria are not as secure when the doors are open compared to our tabletop terraria because of the size and location of the door. Hand feeding collared lizards and earning their trust to the point that they can be handled easily while remaining calm is a good idea prior to using our terrarium design. Otherwise, a plastic Christmas tree storage box can be placed below the front door when it is open to catch exiting nervous lizards and prevent them from escaping into the surrounding environment.
Our raised-bed terraria measure 6′ x 3′. They measure 3′ high at their highest peak, and extend another 1′ below the surface of the surrounding earth at their shallowest depth. Inside, the substrate level is raised to a minimum of 14″ higher than the surrounding earth outside the terrarium. The eastern 2/3 of the length of each terrarium has a mound of earth, stones, and blocks on top of the raised bed, to a height of nearly 30″ above the surrounding earth.
The northern back half of the terrarium is covered and insulated with foam board insulation beneath the roof, as is the front western third. This shelters 2/3 (12 square feet out of 18) of the terrarium from wind, rain, sun in the summer heat, and helps trap heat during the cold winter when the sun is low on the horizon.
The terraria are made from galvanized steel roofing, blind riveted together, with a 2×4 wooden frame around the perimeter of the door frame, top rear, and along the peak. The door is made of aluminum window screening and aluminum window framing and is held in place with clips for window screens. Gaps between the wood and steel are filled with spray foam, then covered with vinyl.
We again use blind rivets and wire to secure the bottom of the terrarium with 1/4″ hardware cloth to keep rodents out and keep lizards in.
We then dig a pit about 7′ x 4′, to a level minimum depth of 12″ at the shallowest corner of the pit. The terrarium is dropped into the pit, and the pit is filled in.
Our property has terrible drainage. We have a hard clay subsoil a few feet below the surface of the earth. Even though our property is near the top of a hill, the ground becomes soggy when it rains. When it pours, water runs along the surface of the earth. Any pit we dig quickly becomes a pond. The raised beds keep the terraria well drained, dry, and comfortable for the lizards. The relatively shallow depth keeps the interior safe for hibernating lizards in the winter; they do not drown when cold rains come in the spring. The mound inside the terrarium collects heat in the sun, acting both as a basking surface and as a big insulating blanket for lizards who dig into and under it in the winter. If a lizard were to dig all the way to the hardware cloth at the bottom, the lizard would have nearly 40″ of earth from the raised bed and mound above it to insulate it from frost during the winter. The mounds work very well to collect and release solar gain though. One fall we accidentally left mealworms out in a bowl near the top of one of the mounds. Although we had below-freezing temperatures and nights as low as the mid-teens over the winter, when we took the tarps off the terraria in the spring, we found the mealworms in the bowl on top of the mound alive and well. They must not have frozen although they were on top of the mound rather than in it.
We cover the terraria with plastic tarps during the winter. We use a double layer of the summer season tarps that protected the tabletop terraria from rain during the summer and then lay them over the raised bed terraria instead once temperatures start to dip into the mid-20s, or if it is going to be cold and rainy. Usually, we can leave the tarps off until about the second half of November. The tarps usually stay on until March, when we take them off for sunny weather, only keeping them on during days with cold rain showers. Usually around the second half of April or early May, weather warms up enough that we aren’t worried about cold rain, and we throw the old, worn down tarps away. The tarps are held down with concrete blocks, old boards, etc.
Fresh water should always be clean and available. As previously described, we use flat-bottomed, straight-sided cat bowls for water.
A second bowl holds meal worms, super worms, or soldier fly larvae, depending on the season (we grow our own insects, and we only grow soldier fly larvae during the summer) and food item rotation. Enough insects are offered in the bowl to last 2 to 3 days. When the worms are completely gone, the bowl is cleaned and refilled. If 1 worm is still living in the bowl when we make our once-daily check, we do not offer more to the lizards in that terrarium until the day when it is gone. It is good for the lizards to feel hungry sometimes. It prevents them from becoming obese and keeps their appetite up when food is available. This encourages them to more eat insects while they are “fresh” and full of the nutritious diet we raise them on, and while they are still coated in supplement. It also encourages them to eat more tropical roaches, as discussed below.
With the exception of soldier fly larvae, which are high in calcium and have a good calcium/phosphorous ratio, all other food items are dusted generously in Repashy Calcium Plus with D3. So generously that a little extra supplement covers the bottom of the bowl. The insects soon shed the supplement, but this particular supplement is eaten by the insects in the bowl, and unlike most, it does not kill them when they eat it. So, putting extra supplement in the bottom of the bowl means that although the lizards are no longer getting the full dosage of supplement by day 2, they are eating insects that have been “gut loading” on the supplement.
Indoors, we use a cat bowl for food; outdoors, we use a screen-bottomed bowl that we make from 4″ PVC pipe, aluminum window screening, and PVC pipe connectors. This type of bowl has a screen bottom that prevents moisture condensation from insects in the heat and keeps them cooler, so they do not drown in their own moisture and do not cook in the bowl. The downside is that supplement falls right through the screen bottom, so when it is off the insects, it is gone and extra can not be in the bowl for the insects to eat. In an attempt to balance that out, we do not offer tropical roaches on days when the bowl is empty and refilled, only offering them on days when there are still worms in the bowl. This encourages the lizards to eat more of the worms fresh when the empty bowl is refilled and the worms still have supplement on them and nutritious food inside them.
In addition to the insects in the bowl, indoors and out, we offer as many tropical roaches as the lizards want to eat every day or two, depending on the time of the year and the lizard’s appetite. The roaches are dusted in Rep-Cal with D3. The roaches are offered one by one or a few at a time until the lizards have had their fill. Indoors, they are fed to the lizards before any empty worm bowls are refilled, so the lizards in those terraria with empty worm bowls are more likely to be hungry and therefore eat more roaches on the refill days. Because the roaches are only available for a short time every day or two, and because they are dropped into the terrarium (indoors and in table top terraria) or offered by forceps (raised bed terraria) the lizards find them very attractive because they are a “novel” food item, unlike the worms which are available more or less continuously. This, combined with our “one after another, a few at a time” feeding approach ensures that the lizards are eating them while they are still coated in calcium/D3. This is especially important when female collared lizards are making eggs.
Baby collared lizards can be sexed from the time they hatch. Males have enlarged scales below the vent on the base of the tail, females do not. Females also usually have a dark spot on each end of the vent.
By the time they are a few months old, additional sexual characteristics develop, including hemipenal bulges at the base of the tail of males, enlarged and darkened femoral pores on the males, as well as coloration differences.
Adults are sexually dimorphic and coloration differences between males and females are obvious. Males also tend to be a little larger, with larger heads, and females tend to have heavier bodies.
As fall approaches, care should be taken to ensure that all collared lizards have good weight before fasting and cooling for the winter. Thin lizards should not be fasted and cooled for their own safety. Cooling can be delayed until the lizards have healthy body weight.
Indoors: In October, we begin fasting the lizards and prepping them for cooling. If one is not ready, we separate and continue to feed it until it reaches a nice body weight, at which point we fast and then cool the lizard. We can delay that process as late as until the new year, and the lizard will still cycle for breeding. Thus, we can give the lizard a few extra months to gain body weight if necessary.
We do not do anything special with lighting when fasting our lizards. We simply remove all food, offering only water. We fast for a 3-week period, during which fasting lizards will start to seek more cold and less heat to conserve fat stores. At the end of three weeks, the lizards are soaked and then packed up and put into the cold room where they rest for the winter.
Outdoor Tabletop Terraria: From the end of July into August, we do all we can to ensure the lizards have good body weight. As September nears, the photoperiod begins to shorten, the weather cools, and the lizards’ instinct to start fasting for winter starts kicking in. This can create a delicate balance paired against the fact that in the tabletop terraria, lizards lack the ability to burrow into the cool ground and reach temperatures necessary to support proper dormancy. It is therefore best if we have good weight on the lizards by the end of July. Usually going into September, many of our tabletop lizards are not eating much, and this trend increases as the end of the season rolls on. When nights are forecast to drop below 50F, we bring the lizards indoors for the winter. Individuals on the thin side can be fattened up indoors before cooling. This is occasionally a little tricky; for some individual collared lizards, the abrupt transition from cool end-of-season weather outdoors to warm lights and a longer photoperiod indoors may be enough to cycle them into reproductive readiness, causing females to blaze orange. In that case, you will need to be prepared for the high likelihood of infertile eggs being laid, and a delay in cooling until the female winds down, likely resulting in the loss of the next year’s breeding. This has happened to one of our females in two different years. Over the years, the few other females and a male that we have needed to put on weight at the end of the season have not had this cycling issue. Matching the indoor photoperiod to the outdoor one could possibly prevent this premature cycling of some individuals, and we plan on doing so the next time the situation arises.
Outdoor Raised-Bed Terraria: These are normally the easiest with regards to conditioning. The animals regulate themselves well at the end of their season, choosing for themselves when to start fasting and when to start cooling in the ground. Usually, these animals dig in and disappear around mid-August to mid-September. This was a bit surprising initially, because we still have several weeks of nice weather here for tabletop terraria when raised-bed animals go down for winter. Especially so since the raised-bed terraria are designed for solar gain and for protection from chilling winds, so temperatures remain nice inside of them even as weather cools; there are still several more weeks where they could stay up if they wanted to, yet instinct drives them in for the winter.
We have a couple of females whose instinct to hibernate appears to be less strong than others. They do not burrow in with the others, so we bring those females in for cooling indoors when we bring in the tabletop lizards. We return them to their raised-bed terraria the next spring when their fellows begin to unburrow, emerging from their winter’s rest. These females may just be accepting the better climate of these terraria and would eventually dig in on their own, but thus far we have played things safe and brought them indoors for cooling rather than waiting to find out.
The last thing we do prior to cooling our indoor and tabletop lizards is to soak the lizards for 20 to 30 minutes. If there is anything left in their digestive systems after 3 weeks, the soaking encourages them to defecate. It also ensures they have clean skin and helps them to achieve the best possible hydration.
We then place them in a plastic storage tub with a petri dish full of water for drinking and move them into the cold room, where they are kept in the 50s for the duration of their hibernation period.
During hibernation, they do not sleep constantly, alternating instead between sleep and a restful awake state where they do not move about much, but they will drink if thirsty.
There is a north-facing window in our cold room, so the lizards are exposed to indirect natural lighting and the natural photoperiod of the year.
Decades ago when Scott was young, he kept hibernating lizards in an unfinished room in the basement that remained in the 50s year round, and that room did not have any lighting. That room worked just as well as our current cold room, which may be to be expected considering collared lizards in nature as well as in our raised-bed terraria spend the winters below ground in burrows where there is no light.
Once a week, the lizards are checked and their water is refilled before it evaporates completely.
At these temperatures, the lizards lose very little weight for up to several months.
Our tabletop collared lizards spend the winter in the cold room from the time the night temperatures are forecast to drop below 50 (usually early October) until late spring when night temperatures in the extended forecast remain above 50 (usually early May).
Two months in the cold room is enough to bring animals into breeding condition. If this is your first experience cooling lizards, 8 to 10 weeks would be the safest for your lizards.
The condition of our lizards is carefully monitored throughout brumation. If they start dropping weight or looking dehydrated, their metabolism has kicked in; they have started burning fat and their cooling should be immediately concluded for that winter.
Just as we have found complicated changes in lighting and temperature unnecessary prior to cooling, we simply bring the lizards out of the cold room and return them to normal conditions at the conclusion of hibernation. They begin feeding within a few days, slowly becoming more active until they reach their usual activity levels.
3 to 5 weeks after coming out of hibernation, our collared lizard females begin showing vibrant orange breeding coloration in bands and spots across the body, and we see our males courting them.
During breeding season, males bob their heads, move in circles, and rub their femoral pore secretions on terrarium furniture as well as on females themselves, and breed with the females.
Eggs are laid in the pre-described nest boxes in our tabletop and indoor terraria. In our raised-bed terraria, females select suitable nesting sites at locations of their choice, which combined with these females continuously improving their burrows during the summer months, makes finding nests and safely digging the eggs up more difficult than in the tabletop and indoor terraria. Because of this, we sometimes opt to allow eggs to incubate and hatch right inside raised-bed terraria, and remove the babies after they have hatched. When we do this, we temporarily move the adults to a tabletop terrarium before the first eggs are expected to hatch.
One important note about the nest boxes not previously mentioned: When we fill nest boxes with organic garden soil, we moisten it so that it is slightly damp but not soggy, and we keep it that way throughout the nesting season. After dampening it, we take our hands and tamp the soil down. This allows the females to dig burrows without the soil collapsing.
Females come out of the nest boxes after laying, looking noticeably more thin and covered in organic garden soil. They usually take a bath in the cat bowl soon after, leaving the water in the bowl dirty.
When we observe that situation, we remove the nest box from the terrarium and carefully dig up the eggs.
Our incubation boxes are airtight Rubbermaid and Ziploc food storage boxes. We have learned the hard way that not all food storage containers are airtight, so we now stick with those two “safe” brands.
A large container is not needed for collared lizard eggs, and we have hatched clutches in relatively shallow containers with just enough space to keep eggs an inch or so apart, but we tend to use large “shoebox” sized containers for most of our lizards nowadays.
We prefer containers with clear lids so that we can check the condition of eggs without opening the container. We keep our containers sealed airtight to prevent water loss from evaporation, keeping humidity constant throughout incubation. We only open containers occasionally to check on an egg that might be bad, and to remove it if so. Otherwise, containers remain closed and sealed until lizards have hatched and are ready to move into terraria.
Containers are half-filled with an incubation medium. The media we have used include vermiculite (soaked quickly in water before squeezing as much water out of it by hand as possible), and perlite (mixed with an equal or slightly less weight of water). Nowadays, we really like the “Hatchrite” product. We have been using only this for several years now because it keeps things easy. Basically, it is perlite that has been pre-moistened so you don’t need to weigh it and mix water in yourself, saving time. Be sure to store it in an airtight container.
When we dig up eggs, we carefully remove each one from the nestbox, laying them on one side in the incubation box, halfway deep into the incubation medium and set at least 1″ apart. Further apart is better in the event that a bad egg becomes moldy.
We try to set eggs with the same side up that we found them in the nest, but we don’t make too much of a fuss about it. One of us has been breeding lizards for over 30 years and is somewhat clumsy, rolling an egg or two almost every time when digging them up; even occasionally over the years dropping incubation boxes on their side when lifting them out of the incubator to check boxes below, mixing up the contents so the eggs had to be reset in the substrate randomly. Turned lizard eggs haven’t ever seemed to have a problem surviving and hatching in our experience.
Once all of the eggs have been set in the incubation box, the lid seals the box and we record the date and terrarium the eggs are from on the lid. The container is then placed in the incubator. We have incubated collared lizards from 83 to 88F, but have read their successful incubation range is much larger; we have read of successful incubation down into the 70s up to about 90F.
Most of our females to date have laid clutch sizes of 6 or 7 eggs on average, with most females laying 2 to 3 clutches per season.
Incubation here has taken 7 to 9 weeks.
Our babies here have been very easy to raise to adulthood.
Hatchlings are removed from the incubator and raised in basic tub terraria. We use Sterilite 37 Qt. gasket boxes. These tubs measure 24″ x 18″ x 7″.
These tubs were chosen because the gasket keeps small tropical roaches in the tub, and from the time the collared lizards are a few weeks old, they can jump to the top to catch roaches that have climbed.
We cut the flat center of the lid out and hot glue aluminum window screening over the hole for ventilation and lighting.
A dome work light reflector with a 40-watt bulb rests on the screen near one end of the tub, providing a surface temperature on the floor of the tub beneath the light of around 110F; this placement creates a thermal gradient that gets cooler as you move towards the far end of the tub.
We do not use a substrate; instead, we use coarse sandpaper to rough up the plastic on the bottom of the tub so lizard claws will have traction.
Water is offered to hatchlings in a petri dish lid. When the hatchlings reach 2.5″ snout to vent length, a deep petri dish is used instead. The first few weeks we also lightly mist hatchlings with water once a day from a spray bottle if they appear a little dehydrated.
Once the little hatchlings are thriving and a few weeks old, we no longer need to worry about spraying them for hydration. We have found with most species of lizard that when babies are continually offered water via spray, they never really learn to use a water dish and even as adults cannot remain hydrated from a bowl. Babies forced to learn to drink from a dish quickly figure it out, and always will drink from dishes as adults. This is much better for the lizards, as they are then able to control their own hydration, rather than being at the mercy of the owner’s decisions about when, how much, and how often to spray.
Similar to our adults, we offer growing lizards enough mealworms to last approximately 2 to 3 days and when they are gone, we remove the lizards, wash out the tub, wipe it dry, add more mealworms, and return the lizards to their terrarium.
Mealworms are dusted generously in Repashy Calcium Plus with D3. The worms are poured out onto the floor of the tub with a little extra supplement, which the worms can eat and the lizards might lap up if they feel they need it. (We don’t know that our collared lizards do this, but they might, as some other lizards do, so we do this just in case). Not too much extra, just a little. The worms roam free in the tub, but are soon mostly in the “gutters” that run around the inside of the walls of the tub. This ensures that less dominant lizards in the group can easily find worms and catch them.
When adding worms, we also add a very small amount of leafy greens near one corner away from the heat lamp. This is for the worms to eat if they get hungry and keeps them “gut loaded”.
In addition to worms, we offer 2 to 3 appropriately sized tropical roaches per lizard daily, dusted with Rep-Cal with D3 for lizards kept indoors. We use calcium without D3 for lizards kept outdoors.
The roach that we produce that is most preferred by these lizards is the lobster roach (Nauphoeta cinerea). Compared to the more commonly available in the terrarium hobby dubia roach, this tropical insect is relatively small and is more active, soft, and full bodied. The downside is that these roaches climb smooth surfaces with little difficulty and they will survive for a while outside of terraria. If they can find a humid place they can even reproduce at room temperature. We have not found them to be invasive here in Virginia indoors or outdoors but their hardy nature does keep us from using them in our actual home. Small crickets would be a better choice in the home for most hobbyists.
When the mealworms have all been eaten, we clean the tub. We remove the lizards and place them in a second, deep storage tub. We then spray them gently with a little water until it is deep enough for them to bathe in and leave them to soak for a few minutes while we clean and prep their rearing tub. This ensures individuals who are still learning to drink from petri lids get a chance to hydrate.
We use these simple rearing tub terraria without furniture and substrate because it is easy for the baby lizards, and is easy for us.
The baby lizards can easily find food, find water, and thermoregulate. There are no higher locations for dominant lizards to intimidate from. There is no food bowl for them to become protective of. Everyone gets a chance to eat.
For the keepers, it allows us to see at a glance if there are problems. We quickly observe the status and condition of each individual lizard, whether it is thermoregulating, whether it looks hydrated, whether it looks well fed, and whether it is alert. A quick glance at the floor of the tub will show us if the lizards have been feeding well (worms disappear, droppings appear). The condition of the droppings also tells us something about the health of the lizards.
We clean and refill water daily.
With all lizards, if you take a group of hatchlings and raise them together, one individual in a group will become dominant and eat more and grow faster; another individual will lag behind, and the rest will be somewhere in between.
To counter this, we measure each lizard every time we clean the rearing tub and remove lizards for soaking. We measure snout to vent length (svl): the length from the tip of the nose to where the base of the rear legs meets the tail when viewed from above. Our hatchling collared lizards measure almost 1.5″ snout to vent when they come out of the egg. Every time the lizards cross a new 1/2″ mark, snout to vent, we pull the lizard from the group and put it in a new rearing tub with lizards within that 1/2″ range. So for example, when the first hatchling reaches 1.5″ svl, we start a new tub. In the coming days, as each clutchmate reaches that mark, they are transitioned to the new tub from the old. As soon as a dominant individual is removed from a group, a new one rises to dominance in the old group; growth of that lizard takes off for a while. Shuffling groups like this according to size prevents huge size differences and prevents the least dominant from failing to thrive. We have found that for most of our collared lizard clutches, growth rate is so uniform that mostly only 2 rearing tubs have been necessary. Only occasionally have we needed a third because of a large spread of sizes during growth.
Using our rearing method, growth of these lizards is very rapid. Hatchlings are mostly grown in 3 to 6 months (still some growing, color changing, and maturing left, yet large enough to be put into adult terraria). When the lizards have reached this age, they are over 3″ svl and may safely be placed in groups with older adult lizards. First breeding generally happens after they have reached adult size and hibernate over a winter (1 to 2 years old depending on whether they reach adult size in time to hibernate that first winter). To date, we only hibernate adult lizards and leave juveniles up and growing over the winter months.
