The sidewinder is a small rattlesnake from the southwest of the United States and the northwest of Mexico. Hallowell was the first to describe the species (as Crotalus cerastes in 1854) and L. Klauber described the subspecies C.c. laterorepens in 1953.

The habitat of Crotalus cerastes is sandy deserts, with little or no vegetation (creosote bushes), and sometimes rocky hills. The difference between the three subspecies (aside from geographical variations) is primarily their size, with C.c.laterorepens being the largest. Furthermore, the first segment of the rattle of C. cerastes cerastes is brown but is black in C.c.cercobombus and C.c.laterorepens.

All three sidewinders have the characteristic elevated scales (horns) above their eyes, which it is thought protect the eyes when digging in the sand. The colour of the three species varies from yellow, through light brown to grey with the belly normally a creamy white colour. All three sidewinders have 28-45 red-brown spots along the length of their back. Along the length of the back are 141-146 scales.

Diet

The diet of Crotalus cerastes consists primarily of mice, kangaroo-rats and lizards. Funk (1965) also mentioned birds (sparrow) and small snakes (Arizona, Chionactis, Crotalus cerastes and Sonora). By nature Crotalus cerastes is primarily nocturnal and cars kill many snakes while they lie on the (still) warm asphalt.

In spite of their small size, they are still proper rattlesnakes. The venom is potentially deadly and the only reason that bite accidents normally are not fatal is because of the small quantity of venom that is injected. The rattle is well-developed and can be heard from a long distance.

My animals

My animals are a male and a female Crotalus cerastes cercobombus. The male (captive bred in 1993 in Germany), which I bought in February 1996, was, and still is, about 40 cm long. It was placed in a terrarium measuring 100-50-50 cm and heated using a 60-watt lightbulb placed over a rocky cave. As a substrate I use sand, some rocks and cactus wood. A small water container is also present in the terrarium. The daytime high temperature is set to 35° Celsius under the lightbulb and 22° Celsius at the other end of the terrarium, giving a gradient for thermo-regulation. At night the temperature is allowed to fall to 20° Celsius.

The male is a moderate eater who eats about six mice between two hibernations. After I had had the male for about six months, I bought a beautiful looking female at a snake convention. I could not be happier, but the very next morning she died.

Several months later I bought ten one-month-old juveniles. Each animal was placed in a transparent shoebox with sand as a substrate, a hiding-box and a water-container. These shoeboxes were placed on a heating strip. In the beginning all the animals refused to eat, but after several force-feedings they all took pinkies willingly. Prey was offered every 7-10 days and the juveniles did well. When the animals were about four months old they began to die, one by one. After research there was no cause found. All the young ate well and then died one or two days later (if there is anyone who has any idea why, please let me know).

After this disappointment I bought an adult female in October 1998. Because I knew the owner and had seen the animal lots of times at his house I was sure I could place the two animals together. Well, that was a hit. I put the two together at 1800 hrs. and ten minutes later they were in copulation until 11.20 hrs. the next morning. This kind of mating was seen daily over a long period and by the time the animals were placed in hibernation there were 162 hours of mating on the record. The female had eaten the entire time, sometimes even during mating.

The animals were placed in hibernation in November 1998 at a constant temperature of 15° Celsius. In March the animals were placed back in the terrarium with the normal heating regime. The female started eating right away but the male only wanted to mate. Maybe this is the time to mention that according to René Thijssen no two males can be kept together. He has seen that some males, who were kept together for a long time, starting to bite each other heavily for no apparent reason.

The actual breeding

In the next weeks, I observed numerous matings. The female always stayed in the warm area of the terrarium and ate everything she could catch. She became heavier and on the 24th of June she laid eight infertile eggs. After I cleaned the terrarium I offered her two mice, which she took like there was no tomorrow. Much to my surprise, the two lovers were in copulation the next morning.

To be short, in October there were another 130 hours of mating on the record. But what went wrong the last time? Was one of the animals infertile, or was the female already pregnant and did the eggs die during hibernation? After discussing this with my friend René Thijssen we decided to use the following technique. The animals were not placed in hibernation and a 15-watt heating pad was placed in the rocky cave. This was heated twenty-four hours a day, seven days a week. The light bulb was left on the normal schedule, giving the animals the chance to select their favourite spot. It was curious to see that the female stayed in the cool area of the terrarium almost all of the time.

During this period the animals just kept on mating and both continued to eat. In the beginning of March the female became extremely heavy and, although her length was just 52 cm, the girth of her body measured about 20-cm. From March onwards she stayed on the heating pad at night with the rear end of her body, but as soon as the light went on she went to the cooler area. Her eating habits were ferocious, 2-3 mice were taken at each feeding and, if I were not careful, she would steal the mouse from the male. From the end of April on she stayed almost constantly on the heating pad and only with the extreme temperatures in the first two weeks of May would she sometimes leave the hotspot.

On the 9th of May she refused food for the first time since 1998. She stayed near a mouse with her head resting on it, as if she wanted to save it for later. After I removed the smelly mouse (after two days) she instantly moved to the warm end of the terrarium. On the morning of May the 14th 2000 I noticed that the light bulb was not working. Since it was 28° Celsius outside I decided to replace it later. When I opened the terrarium (after checking with a flashlight where the animals were) I could see the female dropping a young at the cool end. This was about 2100 hrs.. I decided not to disturb the female and to check every hour. About 2350 hrs. the female was done giving birth. Surprisingly, the male was in the far end of the terrarium all this time, while normally they were together constantly.

I took the adults out of the terrarium. The normally docile female was very aggressive at this time. Then I took all the cage furniture out to find the newly born young snakes. The result was twelve live young and five infertile eggs. The juveniles were placed in shoeboxes with a small drinking container and a shelter. The boxes were placed on a heating pad. As a substrate I used corn, which I have now been using for the adults too for about a year. Now I have to wait and see if I can get the juveniles to adulthood.

I have already had a good tip from René Thijssen. He has bought several young sidewinders in the past and they all survived. One of his techniques is to give all of the juveniles a drop of water on a regular basis. This is done by placing a drop of water on the juvenile’s mouth with a pipette. I cannot say if this method works but it is worth trying, who knows. My experience with young Bitis shows that young snakes of this species have to learn to drink. In all rattlesnake literature it is said that C.cerastes get all the moisture they need from the prey animals that they eat but perhaps this is not the case.