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How to incubate your eggs.

There are many guides on the internet with regards to how to incubate Leopard Geckos. It can be bewildering to the initiate to the process - but with a bit of perseverance all will become clear.

I'll attempt to explain the basics that you need to know and also tell you how I do it. Once armed with the necessities you can then go forth and try it your way based on many of the other methods out there - or decide to just emulate my methods - the choice is yours!

The main requirements of incubation are:

  • Warmth
  • Humidity
  • Oxygen
  • Patience

Geckos - sexing, mating and eggs!

Let's start with the geckos first! Naturally you're going to require at least one male and one female gecko here!

Here's how to sex a Leopard gecko. Looking at the photo below you will see on the Female there are no hemipenal bulges and very faint barely discernable femoral or pre-anal pores. The male on the other hand had very visible femoral  pores with easily noticeable hemi penal bulges.


If you ever hear a strange buzzing noise from the tank you know that your male has begun the mating process. If the gecko he is making amorous advances towards does not buzz back at him, he now has confirmation that it's a girl. He will clamber up her back and bite at her neck area sometimes doing a nice little dance with his legs at the same time. Copulation then follows and afterwards he will require some time to clean himself up and make himself presentable again. Keep an eye on him though as if after 20 minutes or so his sexual organs are still outside of his cloacal opening he may have suffered a prolapse which will need a Vet's attention.

With the deed being done and the female of good age and breeding weight - which I recommend to be no lower than a minimum of 45 grams; the eggs will more than likely be fertile. A female by the way can retain sperm for a year so do not be surprised that even without a male in the tank the next clutches are also fertile!

A female will begin laying eggs at about 8 months of age at the earliest but these eggs will more than likely be infertile. In her first year however she should begin laying eggs with some vigour. You can expect a clutch of two eggs roughly every 2-4 weeks for the duration of the breeding season. This is the reason she needs good food and lots of calcium, which also ensures that she does not become egg bound - a condition where she is unable to successfully lay the eggs -which may ultimately need veterinary attention. Studies have also shown that poor calcium levels can lead to in-shell deaths of the embryos -- you see that calcium is so very important!

A gravid female will have noticeable bulges to her sides and the eggs when it comes near the laying date will be clearly visible through her belly skin. Do not be surprised if she begins to refuse food totally a day or two before laying is due. There is simply not enough room in there for food also! I do however give her one or two Waxworms at this particular stage - dusted with calcium. She won't refuse them and it gives her a tiny little boost. After laying eggs she will be ravenous! so take advantage and feed her well for a few days to build her strength back up again.

The season runs for approximately 8 months with a break for the winter. I encourage my geckos to begin the breeding season by use of a programmable light in their Vivarium. I regulate the timer so that in the winter and the spring and the summer they get appropriate levels of lighting. I believe that the duration of lighting is what contributes to the season starting and stopping - you see being nocturnal the little nipper gets much more time to hide during the day in the summer months and this is naturally advantageous to their survival in the wild - less time out at night means less chance of being predated and long daylight hours means lots of time for shelter and growing.

 And a female will roughly lay this many eggs per season throughout her breeding life:

























 step1        step 2
 If you have read through the housing section you will know that I use a moist hide with Eco earth in it. The females love to dig at this time and they always lay the eggs without fail in these boxes.    The moist Eco earth maintains good humidity and warmth for the eggs until I discover them and transfer to the incubator. The hides being opaque give a good indication that eggs have been laid as I can quickly see if the earth has been piled up towards the rear - which is a great indicator that the mother has done her job.
 step 3        step 4

 Carefully sifting through the Eco earth with my fingertips - I will find the eggs...

   Here are the eggs in close up

 step 6        step 7

 I gently clean them and then delicately support them to stop them moving whilst I apply a sharpie marker line on the top as I found them to ensure that they do not rotate as I move them or throughout the incubation process as a reference marker for their position.


  I used a special plastic called Polymorph to create a tool for making egg sized depressions in my substrate - but your finger will do just as good a job.


 step 8        step 9

 With the depressions made ready to receive the new eggs I carefully pick them up and transfer them to the substrate. Be careful not to rotate the eggs at all they must go to the incubator exactly as you found them 


 step 10        step 11

I will gently move some of the substrate to provide a slope around the eggs for support and to help warming of the eggs. As they grow the substrate will easily be pushed out of the way.


 Then it's back into the incubator with the rest of their future siblings!


 The Incubator

After a lot of research I decided to go with a dedicated unit called the Herp Nursery 2. I purchased it from company called Cornish Crispa at a price of £100. This incubator is in essence a customised beer fridge. The Herp is an excellent incubator having the ability to both warm AND cool the interior as per requirements. It is a fan assisted peltier type incubator. 

There are a few things you definitely need to know with the Herp though. The first is that the indicator for internal heat on the top is actually a big fat liar! Mind you Herp notify you of this anyway. But here's my findings on it with over 2 years of use now.

I incubate my eggs at a temp of about 84-85ºF. I use a dedicated stand alone temperature and hygrometer inside the incubator to accurately monitor the temps. The unit I use measures humidity and temp in the vicinity of the unit with the option of a second reading from a leaded sensor. By using this sensor and other measuring devices like my new heat probe I discovered the following.

 The top of the incubator gets hotter than the bottom - despite any claims of consistent internal heat. To get a heat of 85ºF in the substrate inside the container - the sensor unit  will register a heat of 85ºF on the same shelf at the peak of the warming cycle. The incubators own temp sensor will be reading 31ºC which is as near as dammit 88ºF! There is a discrepancy of 3ºF here. The unit does not maintain a static temperature inside -it actually fluctuates by about 2ºF -  but the temperature in the substrate will fluctuate very little if at all. The substrate acts like a heat store - as the outer temps drop by 2ºF the substrate and thus the eggs will maintain at 85ºF until the heat climbs back up again.

I have noted a difference of 2ºF between the floor of the incubator and the first shelf. This is actually very handy. This is why: Leopard geckos are sexed according to the temperature that they are incubated at. This temp is most crucial for the first 2-3 weeks - where the sex is "set" by the temperature:

 herp nursery 2

 Temperatures affect sex in the following ways:

 Incubating Temperature

 Resultant sex




 Female - chance of sporadic male


 50/50 Male or Female


 Mainly Male chance of sporadic Female


  "Hot" Females - aggressive and infertile.

As I incubate for mainly females Using the temp discrepancy between the shelf and the bottom of the incubator I can set the sex by placing the container at the bottom for 2.5 weeks and then move to the shelf for the remainder of the incubation. This is because temperature also determines incubation time. 82ºF will give a 60-70 day incubation time and 85ºF gives a incubation time of approx 50 days with 45 days at the highest end. Ron Tremper is the US has proven that incubating at lower temps for the duration creates darker colours and higher temps more brighter colouration. If you had two incubators you can use one purely for setting the sex for the first 2-3 weeks and then move to the hotter incubator to increase the brightness of the colouration for the rest of the incubation duration.

I keep detailed logs of hatch dates and the like and label the containers for identification and other data. I know when a hatch is due and come the time I check on the eggs through the clear window of the incubator every 6 hours or so for new hatchlings.

The first indication for most breeders that a hatch has occurred is a hatchling moving around inside it's container. If you are lucky enough to catch the process you will initially witness the gecko slit the rubbery egg shell. It will then lie there for a while with it's head poking out - presumably that was a hard thing to do! When it has gathered more energy it will exert itself rigorously in short cycles until it eventually frees itself from the egg. It will almost always have some egg sac still hanging from it's belly - I leave the hatchling in there until the egg sac has been absorbed almost totally - this also gives it a chance to dry out a bit- usually about 2-4 hours or so.

Then I will transfer the hatchling to the breeding tank. I do this by carrying the entire container to the nursery and placing it into the tank. I remove the lid and then I will practically always be greeted by a macho display of hissing and screeching! I encourage the gecko to climb out of the container and then promptly return the container back to the incubator for the rest of the eggs to hatch. Each of my cricket tub containers I use for four eggs at a time.

The final element to be considered in incubation is humidity and I cover this in the Incubation Substrate section .


F. Passaro

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