During the weeks prior to ovulation the hard masses that can
be felt in the belly of female Ball Pythons are termed follicles. Follicles are
not eggs. A follicle is an egg cell surrounded by one or more layers of
follicle cells. This mass (the follicle) represents the genetic material the
female parent will contribute to the offspring. The male’s sperm will pass his
half of genetic material to the offspring. Ball Pythons really aren’t gravid,
or pregnant, prior to ovulation. Even though the follicles may be large enough
to palpate, they still have not been fertilized by the sperm so they are not
eggs at this point. Follicles can be reabsorbed prior to ovulation, so just
because your female has follicles, does not mean she will lay eggs.
When ovulation occurs the female will swell at about the
last third of her body. It seems to me that ovulation lasts for about 12 hours
(with peak swelling in the middle of those twelve hours) but I have had females
remain swollen for 24 or more hours. The swelling is easily noticeable – it
looks like the female ate a huge meal. This swelling is caused by the follicles
being released and the female’s efforts to make the follicles pass into the
oviducts. The follicles are fertilized in the oviducts by sperm. The sperm has
traveled to this position in the female’s body in the weeks or days after
mating. While in the oviduct proteins and calcium are laid down in order to
generate the shell. At this point the female is carrying eggs and is gravid.
Eggs, whether they are fertile or slugs, cannot be reabsorbed.