How to Tell If Your Female Ball Python is Gravid (Pregnant) (Video Included)

After mating with a male, you’re looking for signs that your ball python is gravid. Being gravid means that your ball python is carrying fertile eggs, that will eventually hatch into babies.

A gravid ball python will seek cool areas of the vivarium. She may bathe in her water bowl, or lie on her back with her belly exposed. Gravid ball pythons usually go off their food, and refuse meals. Your ball python may have a lumpy appearance as her follicles grow. You will notice a sudden swelling of the abdomen when she ovulates.

Gravid ball pythons lay eggs around 45 days after ovulating. If your ball python looks pregnant, but has not mated, she may have retained sperm from previous pairings. If not, she may be overweight or constipated.

Is My Ball Python Pregnant?

A gravid ball python will lay eggs after it has finished growing and developing inside her reproductive tract.

To become gravid, a female ball python must weigh over 1,500g (3.3lbs) and be at least two years old. She must also mate with a male. This is as simple as putting a male ball python in with your female, and letting them get acquainted.

For the best chance of success, you should pair your ball pythons in the late winter or early spring. This is when ball pythons would be most likely to mate in the wild.

You can lower the vivarium’s temperature prior to this, to trigger mating behavior. However, it’s not strictly necessary, as ball pythons can mate year-round in captivity.

After courting her for hours or days, the male ball python will lock up with the female. Their tail tips will twist around one another’s in copulation. They may stay in this position for up to 24 hours.

If you haven’t seen your ball python lock up with a male, she is probably not gravid.

Can Ball Pythons Lay Eggs Without Mating?

Some animals, such as chickens, routinely lay unfertilized eggs without having mated with a male. In ball pythons, however, this is not the norm.

In ball pythons, the presence of sperm in the reproductive tract triggers the growth of eggs. This means that ball pythons rarely ever ovulate without having mated first.

Uncommonly, however, ball pythons can lay eggs without male contact. These eggs are infertile, and won’t develop into baby ball pythons.

Infertile eggs are called ‘slugs’. They are small, tapered and yellow in color. Fertile eggs are large, oval and white.

According to the Biological Journal of the Linnean Society, ball pythons can also reproduce via parthenogenesis. This is where a female ball python will lay fertile eggs without having mated. These eggs develop into healthy young ones.

Parthenogenesis in ball pythons is extremely rare. If your ball python looks pregnant but has not mated recently, she may have retained sperm from a previous pairing.

If she has never mated, she’s almost certainly not gravid. She is most likely overweight, or constipated. A veterinarian will be able to confirm this via ultrasound, and palpating her abdomen.

Signs That a Ball Python Is Gravid

If your ball python has mated, there’s a good chance she will become gravid. The more times she’s locked up with a male, the more likely she’ll end up with fertilized eggs.

After you’ve removed the male from her vivarium, examine your female ball python daily. If she’s gravid, you’ll soon start to notice the following signs of a pregnant ball python.

Cool Seeking

This means that your snake will spend most of her time at the cool end of the vivarium. She will avoid sources of heat and will try to keep as cool as possible.

Most ball pythons, when cool seeking, will wrap themselves around their water bowl. They may also lie on their backs, with their bellies up in the air. This is called lying inverted.

Ball python cool seeking is a biological instinct that helps to protect the developing follicles (egg sacs). Eggs are extremely heat-sensitive, and can be damaged at high temperatures.

how long are ball pythons pregnant?

Lumping Up

At the same time as cool seeking, a potentially gravid ball python will also start developing her follicles. Follicles are the egg-containing sacs situated in the ovary.

This usually begins around 6 weeks before ovulation. Many follicles will start to develop at the same time. This is also called “building”.

When your ball python is building follicles, she will start to take on a lumpy appearance. You’ll notice this two-thirds of the way down her body. It may look like she’s swallowed several marbles.

According to the Journal of Herpetological Medicine and Surgery, if fertilization does not take place, ball pythons can reabsorb their developed follicles. So, follicle building does not necessarily mean your ball python will become gravid. However, it is a good sign.

Appetite Changes

Ball pythons are finicky eaters at the best of times. But when gravid, ball pythons usually go off their food altogether.

Ideally, you’ll have been feeding your ball python more often than usual before pairing her with a male. This will allow her to build up her fat stores in preparation for pregnancy.

Once she starts building her follicles, your ball python will most likely start refusing food. You can still offer her food, but she probably won’t eat again for a number of weeks. This is normal, and is a good sign that your ball python is pregnant.

Pregnancy Glow

Just before your ball python ovulates, you’ll notice a change in the color of her skin. This is often termed a ‘pregnancy glow’.

Your ball python’s scales will appear brighter and lighter than they usually are. There may be a higher contrast between her lighter and darker scales. It’s most obvious in the head and neck area.

In some ball pythons, this can be so drastic that it looks like your snake has changed color. Wild-type or natural ball pythons may take on the appearance of a pastel or hypo morph.

Swollen Abdomen (Ovulation)

The most obvious sign that your ball python is gravid is ovulation. Ovulation means that your ball python’s eggs have ripened, and they’re ready to be fertilized.

Unlike in mammals, ovulation in snakes can be seen from the outside. Your ball python’s abdomen will look huge, as if she’s swallowed a large meal. It will also feel hard. During this time, your ball python may be more aggressive than usual.

Ovulation is a sudden and drastic change, rather than a gradual process like follicle building. The tip of your ball python’s tail will appear small and thin compared to her swollen belly.

If your ball python is naturally slim, you may notice ridges or bulges, where the eggs are sitting. This is harder to see in ball pythons with more body fat.

Pre-Lay Shed

Approximately 3 weeks after ovulation, your ball python will shed her skin. This is called the pre-lay shed. It will allow her to grow larger, to accommodate her growing abdomen. You’ll notice all the usual signs that your ball python is about to shed:

  • Reclusiveness (hiding)
  • Refusal to eat
  • Aggression and/or skittishness
  • Cloudy eyes
  • Dull, blue-tinted skin with a pink belly
  • Nudging rough surfaces to begin the shed

Before long, you’ll notice a shed skin in your ball python’s vivarium. Roughly one month after the pre-lay shed, your ball python will lay her eggs.

To confirm that your ball python is gravid, you can have your veterinarian perform an ultrasound. According to PLOS One, ultrasounds can also identify infertile eggs (slugs).

How Long Are Ball Pythons Pregnant?

In ball pythons, gestation is measured from the date of ovulation until the date the eggs are laid. The reason it isn’t measured from the day they mate is that ball pythons can retain sperm.

A female ball python may become gravid several weeks or months after she mates with a male. During this time, she retains the sperm in her body, and waits until her follicles develop. Only after ovulation will her eggs become fertilized.

From the moment of ovulation, ball pythons are gravid for approximately 44 to 50 days. You will notice your snake’s abdomen getting bigger throughout this time, as the eggs grow.

When your ball python has her pre-lay shed, you’ll know there’s about a month left. This is a good time to start setting up a humid nest box, and an incubator for the eggs.

Your ball python will lay between 1 and 13 large white eggs (the average clutch size is 4-8). You may also notice some smaller, yellow eggs – these are called slugs, and they are infertile. After being laid, the fertile eggs will hatch after 50 to 60 days.

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Lou Carter

Hi, I'm Lou. I’ve always been fascinated by snakes and reptiles. That’s why I set up – to answer every question that you could ever have about snakes as pets (and how they survive in the wild.) I hope that you find this website useful!

Cite this article:

MLA Style: Carter, Lou. "How to Tell If Your Female Ball Python is Gravid (Pregnant) (Video Included)" Snakes For Pets, (January 21, 2021),

APA Style: Carter, L. (January 21, 2021). How to Tell If Your Female Ball Python is Gravid (Pregnant) (Video Included). Snakes For Pets. Retrieved January 21, 2021, from

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