How to Breed Giant Day Geckos (Phelsuma grandis)

I previously wrote about achieving a lifelong dream by purchasing some Giant Madagascan Day Geckos (Phelsuma grandis).

I also mentioned that I’d been lucky enough to land an adult breeding pair of these incredible little lizards.

I’m thrilled to report that I have now successfully bred this species.

In this article I want to discuss some important tips and discoveries for anyone else hoping to breed day geckos for themselves.

The Mating Process

Let’s start with the easy bit. If you’ve got a breeding pair of Phelsuma grandis then getting them to mate shouldn’t be a difficult task.

Mine are currently housed in a glass Exo Terra that is 60cm tall, 45cm deep and 45 long. They have full-spectrum lighting all day long and a ceramic heater that provides a basking spot of around 25’C.

They’re fed a mixture of Repashy gecko food and an assortment of livefood. Livefood is dusted with a calcium powder.

Under these conditions both of my specimens have gained weight and look in fantastic condition.

Once they’re in good health the breeding seems to “just happen” with no additional input required. While I have yet to see actual mating occur (I assume it happens in one of their hides) I do routinely see the (bolder) male cleaning his vent region soon afterwards. I assume this is a sign of a successful mating.

If you’re hoping for successful egg laying there are two specific tips I would:

Ad Lib Vitamin Supplementation

While I feed a range of live invertebrates to my geckos whenever I offer waxworms they’re placed into a shallow food bowl. This prevents them from burying themselves in the substrate.

It also makes “dusting” them easy; I just add a little powder to the bowl, throw in some waxworms and shake the bowl around until they’re all covered. There’s always a bit of the powder left at the bottom of the bowl but that’s hardly a concern.

Interestingly, however, I have found that even after the waxworms have been consumed the female seems to deliberately come and consume the remaining powder. She only eats a tiny amount at a time, so I assume she is just taking what she needs rather than “gorging” on it.

I have now started to leave a little bowl of the mineral powder in the tank so that she can supplement her diet whenever she desires.

Provision of Suitable Nesting Sites

Giant day gecko eggs have a tough outer shell, and tend to be laid somewhere private within the cage. While my female has laid a few single eggs, most of the eggs I’ve had have been pairs – which are glued together.

The eggs are surprisingly large for such a small reptile, so it is reasonably easy to see when your female has laid them. One day you’ll see her at the basking spot looking very large indeed, and the next she has obviously lost a lot of weight. The difference is likely to be the eggs she produced recently.

What we don’t want is your female gecko becoming egg-bound because she can’t find anywhere suitable to lay her eggs. The provision of suitable nesting sites is therefore of paramount importance.

Here you have a couple of different options. Firstly, I include an assortment of silk plants in my day gecko vivarium, and she has used these as cover to lay eggs before. These were found in a dark back corner, on the vivarium substrate, hidden behind the vegetation.

That said, I’ve had much better results with an alternative solution: bamboo.

I bought a few lengths of bamboo of a large enough diameter that the female gecko could climb inside. This amounted to a width of about 3”.

These were then sawn into pieces that would fit into the vivarium, and the dividers that mark the different sections of bamboo were knocked out (chisel and hammer) until there was enough space in each piece of the female to fully conceal herself.

These were then placed into the tank, ensuring she should easily access the top of each one. It is into these pieces of bamboo the female has laid virtually all her eggs.

Incubating Giant Day Gecko Eggs

When your female becomes noticeably thinner overnight you’ll know that she’s probably laid eggs recently. These are most likely to be in any bamboo pieces you’ve included in your vivarium setup, but be willing to look thoroughly around the tank to find them.  

I don’t advise leaving the eggs in the vivarium, as while they may still hatch, managing baby day geckos is no easy task. Having the eggs hatch in a controlled environment makes your life a whole lot easier!

Instead, I recommend removing them to incubate them separately.

Retrieving the Eggs

Eggs laid on the substrate are easily retrieved. They can just gently be picked up, taking care not to “tip” the eggs. The upper surface of the egg should remain so, or the baby gecko inside may not survive.

Retrieving eggs from inside a piece of bamboo has be slightly more problematic. As the eggs are hard-shelled, I have succeeded in using a 30cm long pair of tweezers, as sold for snake feeding, to gently pull them out. This is preferable to tipping the piece of bamboo upside down.

Building an Incubator

There are two ways to incubate day gecko eggs. If you want to maximize your odds of success then you may want to consider investing in a proper reptile egg incubator. This is certainly the safest option.

However, at the time that my day geckos started laying eggs my incubator was already in use with a range of other breeding projects. I therefore took an alternative route, placing the eggs into a plastic tub and warming it on a heat mat.

Incubation Conditions

As an incubator I use a plastic container with a substrate of vermiculite. The vermiculite is soaked in advance, then squeezed to remove any excess water. The day gecko eggs are gently placed on top of this substrate, and a lid (with ventilation holes added) is placed over the top.

I routinely check the substrate, and spray it with a houseplant spray gun twice a week to keep humidity up.

My Phelsuma grandis eggs have hatched successfully when incubated at around 20-25’C. The temperature in my “animal room” does drop a little at night naturally, so this temperature naturally “cycles” through a 24 hour period.

Under these conditions the eggs take roughly 3 months to hatch – though this is only a loose estimation as I can never be 100% certain how long the eggs have been in the adult’s vivarium before I discover them.

Rearing Baby Phelsuma grandis

One day you’ll get home from work to discover – to your excitement – that there is at least one baby gecko sat in your incubator. Even though eggs are typically laid in pairs, the two hatchling geckos may hatch out at quite different times so don’t throw any unhatched eggs away for some weeks.

So – what do you do at this point? How do you ensure your hatchling Phelsuma get the very best start in life? Here’s what I have found to be effective…

Cages & Vivariums

Just like adult day geckos, juveniles require warmth and ultraviolet (UV) light if they are to thrive. Equally, baby day geckos are very small, and unbelievably fast moving. So you’ll want to do everything you can to prevent them from getting loose in your home!

I use a 30cm x 30cm glass Exo Terra. I have found that by ensuring the cable doors are shut in the lid such a cage easily prevents escape. I’m a fan of Exo Terra glass vivariums because the bespoke hoods make adding a source of UV light very easy indeed.

The mesh top also makes it easy to spray the tank regularly without having to open it. They’re also easy to heat and look great.

I simply take the plastic tub with the new hatchling in, open up the Exo Terra, place the plastic tub inside, remove it’s lid, then close the Exo Terra. In time, the baby gecko will crawl out of the tub and into the vivarium, at which point the incubation tub can be slowly and gently retrieved.

Environmental Conditions

As mentioned, baby day geckos are small and fast, so I recommend setting up a cage for your hatchling that will make maintenance as easy as possible for you (and, by extension, as safe as possible for your pet).

The setup I have been using successfully in recent months is quite simply. It involves a substrate of coco fibre. A water bowl is added, and the water replaced regularly to keep it fresh.

Onto this substrate a range of vertical hides are added – primarily pieces of cork bark and silk plants. This creates places for your baby gecko(s) to hide away from view and feel safe.

Assuming you have the temperature and UV levels right this really is all that’s necessary in the early days.

Feeding Hatchling Geckos

Hatchling Giant Day Geckos rarely seem to come down to the ground of their tank, preferring instead to remain up high. This can complicate feeding and watering. Instead, you need to think about how they’ll get the food and water they need from up to 30cm off the ground.  

While I do provide a water bowl “just in case” I have never seen a baby come down to drink out of it. I therefore like to heavily spray the tank every couple of days, at which point you’ll often see the baby gecko(s) drinking droplets from the sides of the tank.

Feeding offers similar issue; anything that doesn’t climb is unlikely to be of much interest.

For example, pinhead crickets seem to receive very little interest from my hatchlings.

Instead, I rely on four main food sources:

Fruit Flies – Probably my favorite food source for new hatchlings. I buy wingless or curly-winged fruit flies, which are much easier to handle than traditional flies. I simply open up the Exo Terra and tip a load of fruit flies in.

Blow Flies – Just like fruit flies, I buy curly-winged flies. Wait until they turn into pupae, then throw the pupae into the day gecko tank. In those warm conditions they soon hatch, clambering up the glass ready to be eaten!

Hatchling Locusts – Locusts are far more willing than crickets to climb up the glass walls of your vivarium. While adult locusts are a good-sized meal even for larger lizards, the hatchlings are a few millimetres long and perfect for baby geckos. They’re also far more active than fruit flies, and it’s great fun to watch your baby gecko picking them off with precision!

Repashy – Lastly I like to add a little Repashy gecko food to the diet. I bought a feeding station that attaches to the side of the cage with suction cups, so I can place the bowl of Repashy up high, where the baby geckos are perfectly willing to sample it’s sweet flavor.

I try to ensure that there is always food available to my hatchling geckos, in order to ensure everyone gets their fill. As a result I regularly check the cage and “top it up” with food as necessary.

Baby day geckos grow surprisingly quickly, and within a matter of weeks they’ll start taking larger and larger prey. At this point your job gets a whole lot easier, and before long you can start keeping them just like your adults.

As a final note, while hatchlings seem to live together without issue (I have up to 4 hatchlings per Exo Terra) in time they will start to fight. Be prepared for the next step; either separating them out or selling them to other reptile keepers once you know they’re well-established.

Richard Adams

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