Woma Egg Incubation and Hatching

Historically, woma eggs have been notoriously difficult to incubate and hatch successfully, with the most common difficulty having been the apparent susceptibility of the eggs to mold in the presence of excess moisture. As described in Ernie Wagner’s article in the September 2000 issue of Reptiles Magazine, woma eggs "…are extremely susceptible to excess dampness and must be incubated in a drier environment than the eggs of many other python species." The article also mentions one breeder who "…incubated large clutches of black-headed python eggs and woma eggs in perlite with no water, and the eggs did well." Our experience does not support these claims. In fact, we have found that woma eggs can become severely dessicated in as little as a week in the absence of sufficient moisture. We suspect that what the eggs are susceptible to is being wet, in particular, as a result of condensation dripping onto them from the lid of the incubation box. The method that we have developed for incubating woma eggs provides all of the moisture they need throughout the incubation period, and prevents the eggs from getting wet. Our method has given us 100% hatch rates two years in a row. We have used this same incubation method successfully with ball python eggs, and expect that it would also produce excellent results with the eggs of many other python species.

For starters, you need to be prepared well ahead of time. With our female womas, oviposition occurs 30 days +/-1 day following their first shed after warming up in the spring. So when that female sheds, it's time to get prepared. You need a good quality incubator that will consistently hold temperature - you NEVER want to be trying to adjust the incubator temperature while the eggs are incubating. With our incubator thermostat set at 89 F, we consistently get egg surface temperatures of 88.5 F using an infrared non-contact thermometer (if you don't have one, get one - they're as little as $25 U.S. now, and a very good one can be had for only $100 U.S. - a VERY useful tool!). So, now the incubator is on and set to 89 F.

The next task is to set up the incubation container. We use a 32 quart/30 L Steriliteâ plastic sweater box with ten 1/8-inch vent holes near the top (at the bottom of the "handles") at each end. These boxes require a large incubator (we build our own; see our Notes on Incubator Design page), but it's important not to use anything smaller for reasons that will become apparent. Start by placing a 1-inch layer of dry perlite (purchase this and vermiculite from any home and garden center) in the bottom of the box. Then in a separate container make a 50/50 mixture of perlite and vermiculite (we'll call this P/V). Add water in small increments, working it thoroughly into the P/V mixture until the P/V just starts to clump a little bit as you work it between your hands - it will have a more "earthy" texture as compared to its more granular texture when dry. Place about 3 to 4 inches of the moistened P/V mixture on top of the dry perlite in the incubation box. Put the lid on the box and place it in the incubator.

By the next day, the temperature of the box and P/V mix inside it will have come up to the incubator temperature. This is where you fine-tune your incubator thermostat setting. Check the temperature of the surface of the P/V mix using the IR non-contact thermometer. It should read 88 to 89 F. If not, make a slight adjustment to the incubator thermostat and check it again the following day. Once set correctly, continue to check the temperature daily to ensure that the temperature is maintained consistently. You may see small fluctuations (+/- 1/2 to 1 degree F), but don't worry about that as long as you're in that 88 to 89 F range - the small fluctuations often have more to do with how consistent your method is in taking a reading. Only make an additional adjustment to the incubator thermostat if the temperature is consistently low or high over the course of three to four days. You want to have the temperature nicely dialed-in at least a week before the eggs are laid so that you're not still trying to make adjustments as the eggs are incubating. Leave the incubation box in the incubator and the incubator on so that everything is at the correct temperature when the eggs are laid.

When you find the female coiled up around her clutch, you'll have to gently coax her off of the eggs, disturbing the eggs as little as possible. We use the same type of Steriliteâ container for the nest box so that if the eggs are adhered to the box we don't have to risk tearing them while trying to get them unstuck. Instead, we just move the P/V mix from the incubation box into the nest box so that the nest box also becomes the incubation box - we've done this a number of times. Assuming that the eggs are not badly stuck to the nest box, dig a deep depression (almost down to the dry perlite layer) in the P/V mix at one end of the incubation box. Keep the eggs oriented the same way in which they were laid (usually easy because they'll all be stuck to each other in a mound - just leave them all stuck together) and place them into the depression in the P/V mix. Then completely cover them (loosely; don’t pack it down) with about a one-inch layer of the P/V mix you scooped out to make the depression. By covering the eggs, you prevent any condensation on the box lid from dripping directly onto the eggs. Place the incubation box with the eggs into the incubator and let them cook.

Continue to check temperatures frequently (just check the P/V mix temperature without uncovering the eggs), but don't make any thermostat adjustments unless something is drastically wrong. For example, the circulation fan in one of our incubators failed during an incubation and the temperature in the incubator stratified - to about 94F on the top shelf and about 82F on the bottom shelf (of five shelves). One clutch was on a shelf where the temperature stayed about 89F and was fine. However, another clutch on a lower shelf dropped to ~83F, and even though we moved it up to the 89F shelf (it wasn't practical to replace the fan during incubation) only 5 of 10 eggs from that clutch hatched. Don’t learn the hard way – see our Notes on Incubator Design page!

Now the big trick - simple but important. Once every week to two weeks, gently brush/blow the P/V mix off the top of the eggs, check their temperature with the IR thermometer, and inspect them for any signs of fungus, discoloration, or dessication. It is not at all unusual for woma eggs to appear somewhat dessicated ("dried out," "sucked in" or "dented") so unless it appears extreme, don't worry if they do look that way. This method of incubation provides the eggs with all the moisture they need without getting them wet and susceptible to mold. Here's the trick: as the eggs are incubating, moisture will tend to condense on the lid and sides of the incubation box and run down the walls into the P/V mix. At the same time, the P/V covering the eggs tends to dry out. So after having brushed/blown off the relatively dry P/V mix over the eggs and inspecting them, scoop up some of the moister P/V mix from along the walls of the box and re-cover the eggs with it. Repeating this process every week or two continues to protect the eggs from dripping condensation, and ensures that they have enough moisture throughout the incubation period. This process is also the reason it's important to have a big incubation box with the eggs at one end – the large box makes it easy to scoop moist P/V mix from along the walls at the other end of the box to re-cover the eggs with. In a smaller box it's very difficult or impossible to do so.

If all goes well, the eggs should hatch in about 55 to 60 days. We usually leave the eggs uncovered after about 48 days of incubation so that we can keep an eye out for signs of hatching - dripping condensation isn't a concern at that point. The eggs will soften and often dent to varying degrees as hatching time nears. Hatching tends to occur over the course of several days; we’ve had clutches hatch over spans of as little as 3 days, and as many as 7 days. So don't panic if several days after the first egg has pipped there are still others that haven't pipped yet - some just cook longer than others! We set up each newly hatched woma in a small plastic shoebox from our rack system with a moist paper towel as the bottom substrate until the hatchling completes its first shed. This first shed occurs within two weeks of hatching, and the paper towel is kept moist during that period by occasional misting with water from a spray bottle.