General information
The distribution of the Sauromalus ater,also called Chuckwalla is from the eastern dessert side of the mountains in Southern California - east, up to central Arizona. The northern boundary of the area lies in the far south of Nevada and Utah, the southern border of the habitat is the Western Sonora until Guayamas in Mexico. Chuckwallas also live on a number of islands in the Gulf of California.

The climate is characterised as a semi-desert to desert climate with large temperature differences between day and at night time. The area is very dry. The habitat consists mostly of rocks, but there are always places with sand nearby for the females to lay eggs. The Chuckwalla is very territorial, and live alone or in small groups of 1 man and several females. From December to March, they will hybernate. Chuckwallas are diurnal animals, mosly found basking on the rocks during the day. They will retreat to their caves when they sence any danger or when the temperatures get too high.

Sauromalus ater SVL is about 10 inches and they have a tail thats about the same length as the SVL. An adult Chuckwalla weighs about 385 grams. The colors of this lizard will differ from location to location. Most common chuckwallas have a light brown base color with dark or black spots. They are sturdy, strong lizards wich wedge themselves between the rocks by blowing up their body. If they do so they can be very hard to get out of their refuge.

Chuckwallas are sun loving animals, and they are really active during the day, so it is recommended to provide a large enclosure (minimum 1m2) The bigger the enclosure the easyer it is to keep a temperature gradient that is good for these lizards. By making a backwall in the enclosure with several different levels you can create extra floor space. Playsand can be used as substrate, but also a claysand mix with sand or peat.

Provide a proper decorated woestijnterrarium, you can use rocks or flagstones,etc, (make sure to secure them well so they can not fall and crush the animal) but also lighter material as stumps, branches and bark is used. provise adequate shelters (min. 1 per animal). Chuckwallas love narrow hides, keep this in mind when decorating your enclosure.

As Chuckwallas are true sun lovers there can never be an excess of light in the cage. For the heating of my terrarium I use a 60 watt flood lamp, and a 100 Watt UVB lamp. In order to create the right temperature gradient you must have more than 1 lamp. An average daily temperature should range between 30 ° C-32 ° C. Under the baskingspot the temperature can go up to 55 ° C +, under the other spot 45 ° C. It’s important to have a temperature gradient in your enclosure, in other words make sure you have a hot spot for the animal to bask, and a cool end so your chuckwalla can regulate his own temperature. In the cooler places and in some shelters, the approximately 25 ° C to 29 ° C, rising to 55 + ° C below the warmest lamp. A nachttemperatuur of 15 ° to 20 ° is enough, so you probably do not have to worry about the night temps. During the summer months, I keep the lights on for approximately 12-14 hours a day. In winter times I slowly reduce this lighting to 6-8 hours of light a day.

Very important in the chuckwalla enclosure is an UVB light bulb, I use a 100W Megaray. Due to the UVB the animal will create D3 wich is important for its health. Besides that, lizards are able to see more colors than humans, some of wich are in the UVB spectrum.

My animals get a nice and fresh greens salad everyday. Main component of this salad is endive. Supplemented with paksoi, beansprouts, various types of lettuce, chicory, alfalfa, grated carrots, dandelion (if any) grated pumpkin etc.. In the enclosure there also is a dish with bird seeds, red lentils and bee pollen, which are also eagerly taken. As a treat I give them a grasshopper once and a few times a year. I supplement my greens every second feeding with a vitamin / calcium supplement.

The humidity in the terrarium is low. One of the shelters can be kept slightly moist so that the animals can withdraw to it when they need. Normally, the animals will take the necessary moisture from the food (greens) offered. I do not have a waterdish in the enclosure, and did not offer any water the last 2 years, and I seldom spray the enclosure. I always offer fresh moistered greens dayly. If your female is pregnant or the animal is sick you can offer a small and shallow dish with water.

Breeding experience
I have bred this species about every year since 2006. In January 2006 my female chuck showed some traces that mating did happen, and began to eat more and got really really big. Eventually on June 14, 2006 10 eggs were laid. I had made 3 different nestboxes, with slightly moistered sand, and put them in different places in the enclosure so she could pick the perfect temperature for her eggs. Eventually, she used 1 of them, and then completely covered it with sand, almost all the sand in the cage was moved to the nestbox.

Incubation of the eggs
The eggs were removed from the nestingbox and placed in slightly moistered vermucilite in my incubator. For these dessert animals I use pretty dry vermucelite, and I will add some water when I see the eggs collapse a little. On August 28, 2006 the first animal came out off the egg. No. 2, 3 and 4 followed the next day. The last egg hatched the 3th of September. The eggs were at a constant temperature between 30-32 degrees in a so called “dry” incubator (Jeager), and hatched after approximatly 75-80 day. All 10 eggshatched, which is a good result, but unfortunately 3 animals were very weak and a month later 2 of them died. The third one that died lived for a little longer but did not eat by itselve and was to weak to survive. The remaining 7 animals did really good, and went to an other home after 5 to 7 months.

The juveniles
raising the juveniles is roughly the same as the care of the adult animals. The first 2 / 3 months are very important, if the will survive this period, they will probably grow into beautifull big chucks. The young animals can be raised together the first 3 months, be carefull to watch them closely for agression, and make sure all animals are eating properly. The slightly weaker animals must be seperated so that they can get extra attention. It is wise to give your juveniles the fresh droppings of the adult animals the will eat from it wich will be good for the germs in their stomach intestines. It is also said to be nutritious for them. In addition, they eat the same as the adult chucks. But I have a small dish of water in the enclosure of the young animals, and I spray it twice a week lightly, so they can lick the drops of the enclosure walls. By spraying around the waterdish, you will trigger the small chuckwallas to drink from the static water in the cup.

These young CB animals can be very "tame", because they are used to the interaction with humans.

The Sauromalus is a lively lizard and will adapt well to captivity lizard, provided that the optimal conditions for this animal will be created concerning housing, food, health, acclimatization and heat / light. Especially for the advanced hobbyist this animal is a beautiful challenge, especially because for a healthy captive population we will need a lot more breeding results.

Studbook ESF
Michel and I will take over the Studbook for this species from Henk Zwartepoorte. Because this species in nature is not threatened, and Henk did not have enough time, this Studbook was slightly less active last year. Together, we hope to give the Studbook Sauromalus a new impuls and we want to see how the Chuckwalla is doing in captivity. The studbook / breeding program is really about keeping a healthy population of animals in captivity. By keeping a record of the animals and the breeding a healthy growth of this population may be achieved. The Studbook is also to ensure that knowledge is transferred among members of the studbook, so we can take even better care for our captive chucks. This way not everyone has to find out everything by himselve, questions can be asked at the Studbook keepers and they will try to find the answers whithin the Studbook.


Desert Lizards Captive Husbandry and Propagation (by Randall L. Gray) Krieger Publishing Company Malabar Florida (ISBN 1-57524-160-9)

Sauromalus & Dipsosaurus Verzamelnummer (SDGL / different authors)

Reptilia (The european herp magazine) No 48 The Genus Sauromalus with notes on keeping and breeding Sauromalus ater (author Harry Wölfel)