Like all spiders, jumping spiders need to get rid of their old exoskeleton once they’ve grown out of it. This is quite a tiring job for them and can take anywhere from days to weeks for the full process even though the actual moulting itself only takes a few hours usually. Let’s walk through the entire event and how to spot when your jumping spider may be about to moult, and what to do to ensure it goes smoothly.
So an exoskeleton is pretty much what it sounds like, although it’s not made of bone like what you and I have as part of our endoskeleton. Theirs is basically a protective outer shell that covers all of their body, even over their eyes. Now although this outer shell does have a tiny amount of wiggle room, it doesn’t grow with them as the spider grows, and once the spider is too big for its current exoskeleton, it’s time to get rid of that one and replace it with the next size up.
Before going any further, this is the perfect time to introduce how to measure a jumping spider's age, because we actually do that based on how many moults they’ve been through and not how many months they’ve been alive. You may have seen on the internet or in spider groups people throwing around the term “L4” or “4th Instar”, this is the stage of life the spider is at and means it’s been through 4 moults.
Unfortunately, not everyone uses the same measuring system for the different life stages, so our 1st Instar spiders can be the equivalent of another country's 2nd or even 3rd Instar depending on where in the world they are and which measuring system they use as the spiderlings undergo a few transformations before they even emerge from the nest.
It takes some getting used to, I know, and can lead to many heated discussions on international forums regarding which is the correct way, but I use the following method and the one that the majority of UK breeders use. A spiderlings' very first moult, the one that they go through whilst still inside the egg-sac as their 1st instar. You can always reach out to me, or any breeder you buy from if you want them to clarify it for you before purchasing. Remember you should never purchase a spider that’s under a 4th Instar and reputable breeders should never sell one that small either!
The exact number of moults a jumping spider has throughout its life can vary from species to species, and spider to spider, and the majority of mine have become fully mature by 7-10 moults, but I’ve read of some spiders not being mature until their 12th Instar. Once mature, they won’t molt anymore, will have their adult colours, and will be sexually mature which also means sadly they’re in the final stage of their life.
How often a spider moults depends on how much and how often you’re feeding it. The more you feed it, the more it grows and needs to moult, the faster it becomes mature, but this also means the shorter its lifespan.
Feeding spiders can be a tricky topic to navigate especially for new owners that don’t fully understand a spiders life cycle, and I see so many spiders being overfed through no ill intent of the owners, they’re just worrying their spider is hungry all the time, or just wanting to make their spider is happy by feeding it. So unfortunately there are a lot of chonky spiders that sadly don’t live as long as they could.
Younger spiders up to their 5th Instar I usually feed every couple of days and they moult around every 3-4 weeks. Once they reach 6th Instar I tend to slow down their feeding schedule as it means we get to spend a little longer with them, so the time between moults will also be longer. Spiders can go weeks without food, so don’t worry that your spider will starve if you aren’t feeding it every day. I feed my sub-adult/adult spiders about every 5-7 days depending on the size of the prey they’re eating.
Now, back to moulting! As mentioned earlier the actual process of them whipping their old outfit off only takes a matter of hours, but the process before and after the main event can be days, weeks, and even heading to the month mark. There’s really no set time scale that we can rely on so it’s important to watch and get to know the signs and the behaviour of your own spider, but usually, the older the spider, the longer it takes.
Moulting is a very tiring thing for them to go through and requires a lot of energy, so usually, in the days/weeks leading up to a moult they may become a little sluggish as they store up as much energy as possible, and sometimes they even refuse to hunt and eat.
They will also start to build a hammock that is thicker and therefore whiter than their usual sleeping hammock and may only have one little entrance which they will close over if anything gets too close. During this period they will pretty much do nothing but sit in their hammock, although there are obviously some spiders that like to throw us a curveball and do unexpected things like abandon it and make another one.
It’s important to recognise this stage as once in their moulting hammock do not put prey food in their enclosure as it may disturb or stress them out and lead to a mis-moult. This also goes for once your spider has successfully moulted but is still inside the hammock as they’re very fragile at this point due to their new exoskeleton not having hardened yet, and this process may take them several days. Some prey items can actually injure and fatally wound your spider if they encounter your spider during the period where its exoskeleton hasn't hardened yet. Once your spider comes out of the hammock of their own accord, that’s when you can feed them and treat them as normal.
You may have some questions at this point, and I will answer the most common questions I see people asking as well as what to do when things go wrong. If there are any questions you have that I haven’t answered feel free to reach out and I will add them to the article.
Can I still spritz the enclosure during a moult?
Yes, you still need to provide your spider with hydration by putting a few droplets of water close to the hammock as they may pop their head out and have a little drink if it’s close enough to them, but never spray over the actual hammock as they can drown.
Is there anything I can do to help my spider have a successful moult?
Making sure that your spider has the correct humidity level before, during, and after a moult will massively help. Being well hydrated gives your spider the best chance, and this doesn’t just mean providing plenty of drinking opportunities. A consistently maintained humid environment with moisture in the air is the best thing you can do for your spider's life.
Leaving your spider alone during the entire process is also recommended, and ideally, they want to be somewhere in a room that’s out of the way, nice and quiet with minimal passing foot traffic and noise from things like the TV or kids.
My spider has been hidden away for weeks, is this normal?
Yes, it is. They can go weeks without food so don’t panic! Once they’re ready they will come out of their own accord.
My spider has fallen out of their moulting hammock, what do I do?
Sometimes a spider will fall out or come out of their hammock too early, and this can be caused by anything from being startled or disturbed, or sometimes these things just happen. Your reaction to it can be the difference between your spider's survival, or not.
If you’ve set up your spider enclosure correctly then there should be a relatively soft landing for them on the substrate below, or even plant leaves to catch them before they even hit the floor. Wherever you find your spider has landed, provided it's not into a pool of water, just leave them alone and do not touch them, they will harden up eventually and move.
If you happen to find your spider dangling from their moulting hammock or nearby leaf, get some very slightly dampened moss, position it under your spider as close as possible and very gently you can try to scoop your spider onto the moss, and then lay the moss on the floor of the enclosure. Do not feed or move your spider until it has moved itself off the floor and back up to the top of the enclosure.
My spider has some of its old moult still stuck to it, what do I do?
If your spider has come out of its hammock and still has part of its old moult stuck to it, unfortunately, this is usually caused by its enclosure not being at the correct humidity level, so you will need to revise your parameters to avoid this happening again.
Getting the old moult off can be tricky and there’s sadly not much you can do yourself. What you can do is gently put your spider into a smaller container that has been lined with a damp kitchen towel. Hopefully, the friction of your spider moving around inside the small enclosure as it brushes over the damp kitchen towel, and combined with the humidity will soften the old moult and encourage it to come away from your spider without any long-term damage.
Do not try to hold your spider down and pull the old moult off!
My spider is completely stuck in its moult, what do I do?
Unfortunately at this point, there is nothing you can do for your spider and you may want to think about putting it out of its misery. Once the actual process starts, if they don’t get the old moult off in one go, it will harden and stick to their new exoskeleton. There isn’t anything you can do to reverse this or rectify this I’m afraid.
This also usually happens when you haven’t got its habitat parameters correct and the humidity hasn’t been high enough.
My spider came out of its moult but is missing a leg/legs, will it be ok?
There are some incredible stories of spiders living the rest of their lives perfectly fine despite missing some legs. If this happens to yours, don’t panic! If your spider isn’t mature chances are that the missing legs will grow back with the next moult. If they don’t, this shouldn’t have any huge effects on your spider apart from making it a little wobbly, but you may need to provide some extra help for it by disabling its prey so they can hunt and catch it better, and possibly need to line its enclosure with netting or mesh fabric to help it grip and get around better.
My spider looks completely different from when it went into moult, has mine been abducted by aliens and replaced with an imposter?
No, not usually!😉 Many spiders look totally different after a molt especially after their final molt into sexual maturity. There are even some spiders that have been presumed to be female but have come out of their moult as male. Don’t panic, it hasn’t been replaced by an imposter, it’s just had a little surprise outfit change to keep things exciting.
I hope all of this has helped answer any questions you have, and remember you can always contact me directly if you need further help.
Victoria xx