Giant Spiny Stick Insect (Eurycantha calcarata) Care Sheet

The Giant Spiny Stick Insect is a thoroughly impressive species of stick insect. Growing to some 15cm or so in length these are big, bulky creatures.

Covered in sharp spines they are sometimes also known as the “Thorny Devil Stick Insect”. These spines are particularly noticeable in the males, which possess a particularly large spine on the femur of their rear legs. It has been reported that this spine is so sizeable than in their country of origin it is used as a fishing hook.

Interestingly, if you’ve kept other species of stick insect over the years, then you’ll know that they normally rest off the ground in the twigs and branches you provide.

While young nymphs of the Giant Spiny stick insect may also do this, soon enough the more mature nymphs and adults make their way down to the ground where they spend the vast majority of their time. Indeed, in the wild this species is most commonly encountered on the forest floor amongst leaf litter.

If you’re keen to keep the Giant Spiny Stick Insect then read on for our detailed care sheet…

Wild Habitat of Eurycantha calcarata

Eurycantha calcarata was described by Lucas in 1869. They are most commonly found in New Guinea, which is why they are sometimes known in the hobby as the “New Guinea Spiny Stick Insect”.

Alongside New Guinea, however, they are also found in New Caledonia and the Solomon Islands. Here they typically inhabit moist, humid tropical rainforest areas meaning that both moisture and warmth are crucial for their care.

Giant Spiny Stick Insect Cages

While older juveniles and adults will spend much of their time on the floor of the cage they still moult just like any other stick insect: by attaching their back legs to a twig and then sliding out of the old skin. This means that selecting a cage of a suitable height is important if the the Giant Spiny stick insect is to be happy.

Generally speaking a good rule of thumb here is that the cage should be at least three times as tall as your insects are long.

At the same time, it is crucial to appreciate the amount of time your Giant Spiny stick insects will spend on the ground. As a result, you’ll also want to ensure they have suitable space to move around and feel comfortable. Experts recommend that the cage should be at least twice as deep and wide as your stick insects are long.

For larger specimens of Eurycantha calcarata this means you’ll ideally be looking for a stick insect cage measuring some 45cm tall, 30cm deep and 30cm long. Of course, these are the minimum recommended dimensions, and larger cages will be just as welcome.

When it comes to selecting cages for this species there are three suitable types depending on your circumstances:

Glass Terrariums

Glass terrariums are the “ultimate” cages for stick insects. They’re made from glass, with two neat doors that open at the front. This makes it easy to access your insects for handling, feeding and cleaning.

These cages have a metal mesh lid which allows moisture to escape; crucial if you don’t want mould to start building up in such a humid environment.

Mesh / Netting Cages

A second option when it comes to housing for the Giant Spiny stick insects are specially-made mesh cages. The benefit of such cages is that your stick insects will easily be able climb up the walls, rather than having to rely on climbing up the twigs and branches you insert.

Mesh cages are also typically quite reasonably priced, and as you imagine they offer excellent ventilation. While this ventilation prevents the build-up of mould, it can make these cages difficult to heat in winter. After all, the heat escapes continually.

As a result, while I quite like netting cages I tend to only use them in the summer months when the ambient air temperature is suitable for my insects. For all but the warmest few months of the year I prefer theglass terrariums which still have some beneficial ventilation but their glass walls make them much easier to keep warm.

Plastic Tubs

For small Giant Spiny stick insects, I sometimes use plastic containers as sold in hardware and home decor stores. A few holes can be drilled in the lid for ventilation and these are typically very easy to heat.

These can be ideal for young nymphs, which can otherwise suffer from dehydration, however they don’t look great. After a few initial moults ,therefore, I tend to move my stick insects into a glass terrarium to create a fantastic display. After all, there doesn’t seem much point in keeping exotic pets if you can’t enjoy looking at them, right?

Heating & Temperatures

While the Giant Spiny stick insect might be OK at room temperature during the summer months, for the vast majority of the year they’ll require some kind of supplemental heating. A temperature of around 25’C, plus or minus a couple of degrees, tends to work well for this species and keeps the nymphs growing at a healthy rate.

In most cases the easiest heating option is to use a reptile heat mat. These cost a matter of pennies per day to run, and can simply be slid under the cage you have chosen. Generally these heaters require no thermostat because they don’t get too hot, though some keepers like to use a matstat to be certain their pets can’t overheat on warm days.

If your house is particularly cold you can top up the heat provided by your heat mat by installing a heat lamp in the hood.

In my experience you won’t need a very powerful bulb to keep such a small cage warm; a 25 watt bulb is probably more than enough. If you’re opting to use a heat lamp like this, however, you will need to use a thermostat to prevent overheating.

Finally, if you opt for a mesh cage outside the summer months then you’ll need to heat the cage using a stand-alone heating lamp and thermostat.

If can be a good idea to keep a digital thermometer in your stick insect cage to ensure that the temperature remains within acceptable bounds, allowing you to make modifications to your thermostat settings if required.

Water & Humidity

The Giant Spiny stick insect likes a humid environment, and without it your pets may struggle to moult. The easiest way to do this is to spray their cage liberally every few days with a houseplant spray gun.

Between sprayings allow the cage to dry out slightly, which helps to prevent mould or fungus from getting established. Note that a higher humidity is easier to achieve in an Exo Terra than it is in a mesh cage, where the moisture may evaporate away too quickly.

Larger Giant Spiny stick insects may also benefit from having a water bowl, which they may drink from while they are on the floor of the cage. At the same time, it is best to avoid putting a water bowl into the cage with smaller nymphs who might otherwise drown in even a small volume of open water.

Cage Decor

Traditionally many stick insect keepers include little in the way of tank decor. After all, why bother when the insects spend all their time up in the canopy? For Eurycantha calcarata, however, tank decor can make rather more sense thanks to all the time that larger specimens will spend on the floor of their cage.

Arguably the most important element here is a suitable substrate. This will help your insects to feel comfortable as it will mimic the forest floor in New Guinea.

A whole host of options are suitable. For example, potting compost can work well – if you can be sure that it has no chemicals or pesticides in it (not always easy). Generally it is safer to use a substrate sold specially for reptiles and other exotic pets where you can be sure of its purity.

Over the years I’ve tested a range of different substrates with my phasmids, and my preference these days is for coconut fibre. Don’t worry – it looks nothing like coconut. It’s just an absorbent, soft and pliable compost-looking substrate.

This coconut fibre is also known as “coir” and is available from reptile stores or from ecommerce sites like Amazon. What makes it so great is that it not only looks fantastic but it’s also highly absorbent, which can be useful for keeping the humidity of your Giant Spiny insect cage up.

The second element to consider is providing some suitable places for your stick insects to hide. In the wild the Giant Spiny stick insect doesn’t just sit around in the open; if they did they’d soon be picked off by a long list of potential predators. Instead, they like to conceal themselves in leaf litter and beneath pieces of loose bark.

The first step in terms of a hide is therefore to either invest in some pieces of cork bark or lay some flower pots on their side in the cage. Alongside this, however, you may also want to consider scattering some leaf litter across the otherwise virgin substrate, which not only looks great but allows your Giant Spiny stick insects to behave more naturally.  

Feeding Giant Spiny Stick Insects

Giant Spiny stick insects are herbivorous and will eat a wide range of different plant material. Most breeders use bramble or oak as their standard fare, though they will also eat hawthorn, apple, pear, cherry and beech.

Personally, I focus on bramble, because even in the depths of winter these leaves can be found when most of the other food plants have dropped their leaves.

Like all stick insects, Eurycantha calcarata appreciate fresh, soft, green leaves. Once they have been cut and placed into a heated cage they can quickly wither and dry up, making them far less appealing.

The solution is to place the stems of the food plant into a jar of water, rather like one might place a bouquet of flowers into a vase. In this way, the food plant will probably stay healthy for around a week, after which point you’ll need to change it.

Be aware, therefore, that you may need to take a walk into the countryside each weekend irrespective of the weather if your insects are feed. Lastly, when placing the stems into water be sure that your Giant Spiny stick insects cannot fall into the water and drown themselves.

Breeding Eurycantha calcarata

Giant Spiny stick insects are very easy to breed, and no special conditions are required. Producing eggs is as simple as keeping both sexes together in the same cage; as a reminder they are easy to sex by looking out for the giant spine on the rear legs of the males.

The eggs will fall to the bottom of the cage where they will incubate. They can be left in situ, however generally it is safer and easier to remove them to incubate separately. In this manner you can avoid the risk of throwing eggs away when cleaning your stick insect cage, and you can also keep an eye on them to ensure they don’t become rotten.

Please note that Giant Spiny stick insect eggs can take a long time to hatch. One scientific study found that when incubated at temperatures in the mid twenties the eggs take an average of 101 days to hatch.

All the same, this incubation period is highly variable, with some youngsters hatching sooner, and others not making an appearance for some additional months. In other words, so long as the eggs look healthy (they are not being attacked by mould etc.) don’t get too impatient; one day you’ll arrive home to find all manner of tiny babies crawling around the cage.

Photos c/o AlessiaM87 & AlessiaM8