6. Breeding Pythons – Part 3: Down to business.
...... by Doc Rock
We are now in the heart of winter. Since there is less feeding and cleaning during this period, it is a great time to relax if you are not trying to breed snakes. But if you want to breed your pythons, then it’s down to business because winter is a time that will either make it or break it for you when it comes to the process of making babies. In “Breeding Pythons – Part 2”, I discussed methods of temperature cycling and how this is used to trigger breeding in snakes. As winter is the time when we cool our snakes, it sets the scene for breeding success or failure. If the snakes are not managed correctly through this period, you can end up with ineffective matings which result in a lack of ovulation or unfertilised eggs (slugs) which of course means no hatchlings.
Different species of python will mate and breed at different times of the year depending largely upon the latitude, or altitude, their original genetic line(s) comes from. For example, I have found my Darwin carpets will mate through winter and ovulate in late August, whereas my inland carpets and diamond pythons are not interested in each other until spring and do not ovulate until October/November. I have also found that jungle carpets from the top of the Atherton tablelands, which has an average height of 1,000 m, tend to breed later than carpets that originate from around Cairns. This is not surprising as the temperature falls about 5-6 oC with every kilometre in altitude and so the seasons lag progressively with height. You need to be mindful of this when trying to breed same-species pythons from areas with significantly different climates.
Having sorted out their breeding temperatures, a question I am frequently asked by many breeders is “should I move the male to the female or vice versa”. In the wild, male snakes usually roam their home range in search of females at the appropriate time each year. This is one reason why more male snakes are found in the wild than female snakes. Consequently, as a rule of thumb, I move the male to the female with all the various species we breed. The exception to the rule is the case of the confident female with the highly strung or timid male. I have seen some males have a “stress attack” when moved to a new cage (often with or without a female in it) which makes them sexually ineffective. So as a second rule of thumb, if you have any highly strung snakes, move the more relaxed individual into the cage of the more uptight snake, irrespective of their sexual persuasion.
Unless we are breeding for a specific trait and so want to put a particular male across a particular female, we always mate our females with multiple males. There are a number of reasons why. Firstly, it reduces the risk of a female not being fertilised. This can happen because the male is not producing viable sperm, he loses interest for whatever reason, he decides to go into a shed cycle at a critical time, or because the male injures himself or becomes unwell. There is nothing more frustrating than having a lovely well prepared female ready to breed and have something happen to your single male.
Our second reason for using multiple males with each female is that it seems to stimulate the whole breeding process. If you place a single male and female in a cage and leave them together you will invariably find that the male will mate vigorously for one or two days and then will begin to lose interest. Even if you separate them for a few days and put them back together, after a couple of cycles the male can behave as if very bored (unlike us mammals?). Although in the last article I said that I have found male combat unnecessary to stimulate breeding, a male snake seems to know if a female has been with another male and so will often be re-invigorated in his affections.
Multiple male partners often seem to be stimulatory to the ovulation process too. In species such as womas and black-headed pythons, we have found that using multiple males improved our success rate considerably. At Southern Cross Reptiles, we are constantly hearing from aspiring breeders who want to buy a number of females to go with a single male. Although multiple males are not absolutely necessary and a single male can impregnate many females, with our womas and black-headeds in particular, we generally use a ratio of one and a half to two males per female and have enjoyed a 100% success rate now for many years.
There is one potential consequence of using multiple males which you should be aware of and which is best avoided. Usually, when exchanging the males we are putting across a female, we allow a couple of days rest for the female between mates. However, on one occasion when I swapped one male black-headed python for another within a few minutes of each other, the second male smelt the recent presence of his competitor and viciously attacked the poor female by mistake. If you have ever seen two male snakes get seriously stuck into each other, you would appreciate how much damage they can do to a cage and each other in very little time. I have seen a similar occurrence with carpet pythons that resulted in the female requiring stitches and a wasted breeding season.
Before leaving the subject of males, I should mention that it is possible to get an indication of whether or not a male is producing viable sperm if you have access to a compound microscope. Years ago I went to an auction and bought a great microscope for a couple of hundred dollars (I saw another one recently in a second hand shop). This piece of equipment has proved invaluable over time, both to check faecal samples for any nasties and to check the viability of our male’s sperm if ever I’m worried. To check for sperm, all you have to do is firmly roll your thumb up the tail of the snake towards the cloaca and you can usually press sperm from a hemipene pocket fairly easily. Sometimes by doing this you will also find that you squeeze out a sperm plug (dried sperm), before you can extract a drop of fresh sperm. If you place this drop of sperm on a glass slide and look at it under a microscope fairly quickly, you should be able to see lots of individual sperm bouncing all over the field of view. This is confirmation that your male is producing active sperm.
One behaviour we look for in our snakes when breeding each year, is what we call the daily cycling pattern. Typically it will start with a snake sticking its head out of the hide box after the lights come on in the morning, moving to the basking site for a few hours and then retreating later in the day back to the hide box to conserve heat until the next morning. Often this behaviour is interrupted in the evening by amorous males (and sometimes females) pacing back and forth across their cages until eventually retreating to their hide box for the rest of the night. Once this pattern becomes established through winter in a group of pythons, we usually enjoy a high degree of breeding success when the males and females are put together. Conversely, if the python’s behaviour, basking and daily whereabouts in the cage remains unpredictable we have found reduced success.
The hide box can be an important piece of cage furniture during the mating season and should not be overlooked. Throughout most of the year, it provides a place to feel safe and perhaps thermoregulate by controlling heat loss or gain. To make the python feel secure, a hide box should fit the snake reasonably snugly – say a bit like the family car parking in a standard garage rather than an aircraft hanger. However, a hide box that comfortably fits a single female snake will be very “squeezy” when the male is added during the breeding season. We have learnt that sometimes a female can resist the attentions of a male in a tight fitting hide box, or alternatively the male can have difficulty accessing the female if space is too confined. Consequently, each year about a week before starting the breeding program we change the hide boxes of all our females to allow room for the males. This larger hide box also is better suited for the female to lay her eggs.
During the breeding season we keep detailed records of our snakes mating behaviour which we break into the categories listed below.-
This compulsion to record everything in 5-dimensional detail is not necessary to be a successful breeder and is probably more a symptom of my anal retentive, compulsive nature. However, when you colour code your observations on a spread sheet it not only makes pretty patterns, you can also tell at a glance how regularly a male is performing and which females are consistently stirring up the boys and which are not (see attached figure). This visual analysis can then help the breeder make decisions about which male should go with which female etc.
Finally, I would like to briefly discuss feeding through winter and spring prior to egg laying and whether it is a good idea or not. The bottom line is that we never feed our snakes from the time we begin cooling until the female has either laid her eggs, or we are satisfied she is not gravid. If you have fed the female sufficiently though summer and autumn we find there is absolutely no need to feed. Even a skinny male can last through winter without his desires or his health being compromised. While I have absolutely no evidence that fasting directly affects breeding (which I think it does), it certainly enables the breeder to lower temperatures without worrying about the snakes digestive abilities and subsequent health, it gives the snake a period of fasting which it would often experience in the wild and it means a break for the keeper from feeding and cleaning. A couple of years ago, I came across an incident where a female black-headed python was fed a rat during winter when she was being mated. After many weeks the rat could still be seen bulging in the snake’s stomach. X-rays of the snake were taken by a vet and you could clearly see the undigested rat. Despite increasing the basking temperatures, the snake’s digestion remained switched off and after months it died with the rat literally rotting in the gut. This is the third instance of hearing this type of occurrence with snakes in breeding mode.
So in conclusion, keep a watch on those temperatures and use the behaviour of your snakes to guide and fine tune what you need to do. If your female starts to swell and become turgid, remember the process of yolk formation she is going through (see “Breeding Pythons-Part 1” in Reptiles Australia Vol. 2:4) and don’t make the mistake so many do of thinking she is gravid and stopping the breeding program way before she ovulates. Over the many years I have been involved in the hobby I have found breeding our pythons very rewarding and like so many things in life, the more effort you put in, the better the results and the greater the rewards. Good luck!