I've noticed a wide variety of trends with ball pythons and breeding, both from observations of my own snakes and from what other keepers and breeders have said. However, sometimes there are discrepancies between not only what others have said as compared with what I've seen but also between other breeders. Being a scientist, I can't just let this go; I have to figure out what's going on!

So I've been collecting data--both from my own collection and others'--to try to put actual numbers on some ball python "general knowledge" that is mostly anecdotal or heresay.

The following may be re-posted as long as proper credit is given. All plots were made in IDL.

[ -  Growth Charts -  Breeding Cycles -  Shipping  - ]

Growth Charts
All Adults (up to three years of age)


1. Black dots are individual weights including measurement errors (too small to see).
2. Red squares are averages in 100-day bins with 1-sigma errors (1 standard deviation).
3. Only includes snakes for which I have exact hatch dates.
4. Only includes weights for females up to ovulation (if not before).
5. Vertical dotted lines indicate 1 and 2 years, respectively. The right edge of the plots is at exactly three years.

All Adults except Eu & Fe (up to three years of age)


1. Same as the previous plot except that Eu and Fe have been removed. These two snakes are outliers (not typical in terms of their growth). This gives us better and more accurate errors.

All Juveniles (up to one year of age)

It's a bit difficult to see the first years' worth of growth due to all the points being so close together, and I have additional data in this age range from hatchlings I've sold, so now I plot basically the same thing as before but only up to one year of age. The same caveats apply to these as the ones above with the following modifications:

1. Includes snakes in my collection (black points) and babies for sale or sold (blue points).
2. Averages are in 25-day bins.

All Juveniles except Eu & Fe (up to one year of age)

Same as above but with Eu and Fe removed.

Breeding Cycles
Time between ovulation and the pre-lay shed


Time between the pre-lay shed and laying

Most people say the average time between a female's pre-lay shed and actually laying the eggs ranges from 26 to 30 days, including two of the most popular books by big-time breeders. When my first clutch was laid by a female 48 days after her pre-lay shed (with much freaking out on my part), I wondered how accurate this range was.

The following is a histogram of the time between a snake's pre-lay shed and lay date, including data from my own collection and others'. Twenty measurements are shown (some are for the same snake but different breeding years). This is much different than the usual consensus! If the outlier snakes are removed (48 and 51 days), the mean changes slightly: 33 +/- 4 days. A more accurate range, then, is about 30 to 40 days after the pre-lay shed, not 26 to 30.

One snake in this list (not included in the 20 count) did not shed at all between ovulating and laying.

Thanks to Bob O'Brien, Sue Anderson, Pamela Trentham, and Michael Losoya for contributing data to this plot.

Incubation times


Incubation time with respect to temperature


Shipping temperature fluctuations


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