***I received an email from a boy named Gwen last night which asked something similar to this question. Unfortunately, the email address he typed into the contact form must have been mistyped because it does not work, so I’m responding with this post. Gwen, if you’re reading this, comment on this article or email me again to let me know you got the response (and so I know whether or not I answered all your questions). -Elise
Let me begin by first saying that snakes, unlike chickens, do not often produce eggs on a regular basis if they have not mated with a male. A hen will produce eggs regardless of whether or not the egg has been fertilized by a rooster, yet a hen’s unfertilized eggs (which are the ones we usually eat) are different from her fertilized eggs (which become chicks). A female snake, however, will typically only lay an egg when the egg has been fertilized, and when there is an offspring in that egg. Typically speaking, if a ball python has an egg, therefore, there is a baby ball python in that egg. There have been a number of reported cases where a ball python will lay an egg that has no offspring in it (which are called “slugs” in the ball python world) when that ball python has not bred, just as the chicken’s unfertilized eggs would not contain an offspring, but these are very rare circumstances, and typically do not happen. If your ball python has an egg, assume it has an offspring within it until you can clearly see that it is a slug and is not carrying a baby ball python.
On the topic of a ball python laying eggs completely without a male, it sounds odd, but it is possible, even though it is a very rare phenomenon. A small number of reptiles actually have the ability to reproduce on their own, in a process called scientifically known as parthenogenesis, and more colloquially known as ‘virgin birth.’ In these cases, reptiles of the female gender, with no male interaction whatsoever, will spontaneously generate offspring. Parthenogenesis has been documented in ball pythons, bearded dragons, Burmese pythons, and even Komodo dragons.
More commonly than parthenogenesis, however, are situations where a female ball python who has not mated recently becomes pregnant because she held on to the sperm of a male ball python she had mated with previously. Females that have previously been bred can retain sperm for years in order to become pregnant in the future.