When keeping the larger species of spiny lizard (desert or crevice spiny lizard), the terrarium décor can remain the same, but the terrarium/cage size should be increased. A 30-gallon capacity cage will house a pair of blue or desert spiny lizards, and a 50-gallon terrarium will be adequate for a trio. Of course, as with the smaller species, the larger the cage, the better. In the wild, these lizards inhabit territories at least as large as a human bedroom.

Heating and Lighting for Spiny Lizards

At this outset, let’s mention some suggested parameters of terrarium/caging lighting and heating. All species contained in the genus Sceloporus, the swifts and spiny lizards, are diurnal and heliothermic. That is, they are active by day and are basking lizards. Northern and high-elevation species brumate (the reptilian equivalent of hibernation) throughout the months of winter. Species in the deep south remain active throughout much of the year, remaining hidden and inactive during rainy, overcast weather or during the passage of cold frontal systems.

Although you can keep your swifts and spiny lizards active year-round by maintaining a suitable regimen of heat and lighting, it may not be possible to cycle those species that are normally inactive in winter without providing them with several months of cooling during the winter months. If you do decide to brumate your scelops, full darkness and a temperature in the high 40s or low 50s (degrees Fahrenheit) should be maintained. The hibernating chamber should provide a moderate humidity of 60 to 70 percent, but no actual wetness.

Unless physically impeded, the beneficial output of natural (full-spectrum) sunlight is relatively stable. No matter at what point in its habitat a lizard chooses to bask — high in a tree or on a ground-level rock — the benefits (UVA, UVB and warmth) will be nearly the same. The beneficial aspects of full-spectrum cage lighting, however, are a different prospect entirely, and one that must be carefully considered during enclosure construction. Even the best of the full-spectrum bulbs produce only small amounts of the desired ultraviolet rays, and these are effective for only a short distance. In most cases, the basking spot for your lizard must be 12 inches or less from the bulb. Follow the instructions provided with your bulbs carefully. The best full-spectrum bulb produced will do no good and can be harmful if positioned improperly. Remember that your lizard must always be able to move to a cooler area of its cage and get away from the light. Full-spectrum lighting is now offered in both fluorescent and incandescent styles. While the fluorescent provides only lighting, the incandescent format can provide both light and heat.

Whether in the wild or in captivity, swifts and spiny lizards will warm themselves in one or both of two ways. Arboreal species will simply splay out on a heated or sunny limb or trunk. If the latter, the lizard will often follow the sunny patches as they move, until the lizards are warmed. Saxicolous species not only utilize sunny rocks, but also elevate their body temperatures more quickly by lying flat against a rock surface already preheated by the sun (or a heat lamp).

Of course, unlike the ever-moving sun, cage lighting is usually stationary. It will be necessary for you to position the full-spectrum lighting and the heat where it will best serve the needs of your lizard. Lighting should be available for at least 12 hours a day, and I have had best results when my lighting simulates the normal, seasonally variable photoperiod. A brilliantly lit and sufficiently warmed cage will stimulate these diurnal sun-loving lizards to indulge in normal activity, including feeding, territoriality and breeding. A cage that is insufficiently lighted or too cool will result in lethargic lizards that fail to thrive. Conversely, a cage that is too warm overall will cause the swifts and spiny lizards to burrow or seek other shelter to gain relief, again failing to thrive. Spiny lizards will do well if, in addition to sufficient lighting, the cage is maintained at 80 to 82 degrees with a basking spot of 100 to 108 degrees. Take particular care to have the basking area you provide well within the parameters suggested for the bulb you choose. With the bulb off at night, cage temperatures may be allowed to drop to normal room temperatures (70 to 78 degrees).

Feeding Sceloporus Lizards

Scelops are insectivorous lizards, but not all species or individuals will eat all types of insects readily, so you should experiment. Giant mealworms (Zophobas), regular mealworms (Tenebrio), waxworms (Galleria), crickets (Acheta), silkworms (Bombyx) and other non-noxious caterpillars, and various small roaches of several genera, are all commercially available and excellent food items. If you have nearby fields or meadows that have not been subjected to insecticides, “field plankton,” insects collected with a sweepnet, can be collected during the warm months as a dietary additive. A diet consisting of varied insect species is better for the lizards than a diet of only one or two insect species.

Also of importance is to choose insects of the proper size. All offered insects should be relatively small when compared to the lizard’s head. Select insects with relatively soft bodies, such as subadult crickets and mealworms, that can be easily chewed and are no more than one-third the width of the lizard’s jaws. Even if ample full-spectrum lighting is provided, your feeder insects (with the exception of freshly collected insects from the field) should be dusted periodically with a vitamin D3 calcium powder. Suggested intervals for the dusting would be every 10 days to two weeks for adult lizards and weekly for growing lizards. Scelops will usually stop eating when they are sufficiently filled, but if you find your lizard is becoming obese, cut back on the amount of food offered. 

Compatibility and Breeding of Swift and Spiny Lizards :

Both sexes of all swifts and spiny lizards are alert and territorial. Males of the same species and of closely allied species and subspecies are especially quarrelsome and are particularly prone to skirmishes with each other when they are reproductively active. Unless you have an immense cage containing many visual barriers, it is best to keep only a single pair (or perhaps a trio of one male and two females) to an enclosure.

As mentioned earlier, most species in this lizard genus are easily sexed. Males of most have blue belly and throat patches (rose on one species) of varying intensities and sizes. These flash colors are lacking or greatly reduced on most females. Additionally, males have a thickened tail base and enlarged femoral pores on the underside of each hind limb. All of these characteristics are most enhanced when the lizards are reproductively active.

Breeding activities begin in the spring and continue periodically while the photoperiod is lengthening. With most species, activities decline with the declining hours of daylight. Mesquite lizards, blue spiny lizards, crevice spiny lizards and Yarrow’s spiny lizards give birth to a single clutch of live young annually. All other species of the United States are egg layers.  REPTILES

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Dick Bartlett is a herpetologist/herpetoculturist who has written hundreds of articles and many books, some with his wife, Patti. He has bred 175 captive herp species. A frequent lecturer, he has participated in field studies in North and Latin America, and he has led tours to the Peruvian Amazon.