Snake Egg Incubation
Dr. Jenni Bass
The incubator must insulate the eggs against heat and humidity losses and significant ambient temperature fluctuations. They may be homemade, such as a plastic container, which holds the eggs. This container is then placed inside an insulated box, such as a styrofoam cooler. Or, the incubator can be purchased commercially. Location. Place the incubator in a room that does not experience drastic temperature variations, and where it will not experience undue vibration or jarring.
An incubator should be running for at least 48 hours before it holds eggs to allow you to be sure that temperature and humidity variations are within acceptable limits. The principles of a good reptile egg incubator apply equally between homemade and commercial incubators and include:
Turning function. Reptile eggs should not be turned. Be certain that the turning function can be disconnected in the case of a commercial chick incubator.
Fans. If the incubator has a fan, it should be disconnected as it will lower the humidity within the incubator and likely dehydrate the eggs.
Water baths. Some incubators have built in water baths. This allows for even heat distribution and provides humidity. The same effect can be achieved in a homemade incubator by suspending an opaque plastic container, which holds the eggs, in a water bath in a styrofoam box. In this case, a submersible aquarium heater with a thermostat works well to heat the water. An alternative is to place a dish of water in the incubator, which will increase humidity through evaporation. A hygrometer to measure humidity is recommended.
Ventilation. Good ventilation is crucial, particularly as the hatch date approaches and fetal oxygen demands rise. Some holes or vents should be present in the incubator to allow for the escape of heat and carbon dioxide and for the entry of oxygen. Opening the lid of the incubator briefly, every 1 to 3 days, depending on the number of eggs being incubated, should allow adequate fresh air exchange without cooling or drying the eggs excessively. Indeed, some minor fluctuations within the incubation temperature range are likely beneficial, as that more closely mimics the natural situation. A window will allow you to see the eggs without opening the incubator.
Temperature. In the wild, natural fluctuations occur. In captivity, incubator temperature should be in the range of 82 to 88 degrees Fahrenheit. Recommendations vary, but pythons appear to prefer the warmer end of the range, 85 to 88 degrees Fahrenheit.
Given that the safety margin narrows when the eggs spend more time at the upper end of the range, a more moderate temperature and slightly slower growth rate are preferable. Temperatures above and below the range will increase the incidence of abnormalities and fetal deaths.
Temperature should be controlled by a thermostat, and at least two thermometers (not just the one sold with the incubator) should be clearly visible. Digital thermometers with remote sensing probes work well. A maximum-minimum thermometer is highly recommended.
The temperature must be checked at the level of the eggs and heat should be spread uniformly throughout the incubator. The eggs must not sit on "hot spots" or next to a ventilation port. Commercial incubators are usually equipped with heating coils and thermostats. In the case of a homemade incubator, the heat source can be a heating coil or a submersible aquarium heater. It is not recommended that the incubator simply be placed on a heating pad, as this is a potential fire hazard and does not allow particularly fine temperature control.
Orientation of the egg. Avoid changes in orientation during incubation. The side of the egg that was uppermost when the egg was placed in the incubator should remain so for the duration of incubation. Breeders of reptiles often use a pencil to gently mark the top of the egg with a small cross.
Substrate. The substrate in which the eggs rest can be potting soil, sphagnum moss, sand or vermiculite. It is best to use a substrate that you know has been used successfully, as detrimental effects on the egg are possible should the chemical make up of the shell react with the substrate. The eggs should be nestled no more than half way in to the substrate.
Humidity. Humidity affects the ease with which oxygen enters the egg through the shell and the rate at which carbon dioxide leaves. For the incubation of snake eggs, the substrate should be moistened. Recommendations vary, but as a guide, a weight ratio of 2 parts substrate to 1 part water should work. The substrate must be damp, not dripping, when squeezed.
The moisture level must be checked regularly during incubation and water added as necessary. Some authors suggest misting the eggs with tepid water or covering the eggs with sphagnum moss to increase humidity or to slow evaporation. Either technique may help if humidity is too low, but moistening the substrate interferes less with the egg itself, and so is preferable. Use a hygrometer to measure humidity. Ninety percent humidity is recommended for many species, but be sure to check the specific recommendations for your particular reptile because humidity and temperature specifics are determined by the species being incubated.