It’s natural to worry if your tarantula stops eating, especially if the fast lasts for more than a few weeks. But this is perfectly normal adult tarantula behavior and generally nothing to worry about.
Which Tarantulas Can Last Longest Without Food?
Adult tarantulas can survive without food for far longer than spiderlings, and females will usually be okay for a longer period of time than males.
There’s a lot of variation in dietary requirements between different tarantula species. More montane species normally have slower metabolisms – the Chilean Rose Hair Tarantula (Grammastola rosea) in particular has been known to fast for over two years on rare occasions! Lowland species will need food more frequently.
So How Long Can a Tarantula Go Without Food?
There are plenty of reports of tarantulas fasting for 12-18 months or even longer on occasion. This isn’t normal, but it’s certainly not unheard of. Tarantulas have exceptionally slow metabolic rates and are very good at conserving energy when they need to.
Spiderlings are the exception, as they have smaller reserves and grow much more quickly than adults. They’re still hardier than you might expect, and going away for a week-long vacation is unlikely to be a problem. But if your spiderling hasn’t eaten for much longer than that, there may be cause for concern.
A tarantula that has recently molted will also not survive as long without food, but that’s mostly because they won’t have eaten for a long time already.
If your adult tarantula looks healthy but hasn’t eaten for a few weeks or even a few months, understand that many tarantulas go through completely unpredictable feasting/fasting cycles. Try not to worry.
What If My Tarantula Doesn’t Look Healthy?
Then you might have a serious problem. Take a good look at your tarantula’s abdomen. If it looks shriveled or shrunken, then that’s a sign that the tarantula is undernourished or dehydrated.
Make sure your spider has fresh water in a tarantula-safe shallow bowl and offer a gut-loaded cricket or two. If nothing changes, you might want to see an exotic pet vet, but I’m afraid there’s probably not much he/she can do to help.
What Else Should I Look Out For?
Make sure you’re providing your tarantula with the conditions it needs to survive and thrive. Take a look at the tarantula care sheets on this website or elsewhere to double check you aren’t doing anything wrong. Humidity, temperature, substrate, shelter etc. can all make a big difference.
Otherwise, just keep offering food periodically. If everything else is fine, then your tarantula will start eating again eventually.
Why Do Tarantulas Stop Eating?
The most common reason for a tarantula to stop eating is an upcoming molt. The pre-molt period can last for a few months, and your tarantula usually won’t eat at all for a large part of that time. You’ll probably find that they have a much bigger appetite when they’ve finished molting!
Even without an upcoming molt, tarantulas will sometimes go off their food for unknown reasons. These fasts can last for a few weeks or many months, but again, it’s nothing to be concerned about unless your tarantula’s abdomen is shriveled.
Tarantulas are generally good at regulating their food intake according to their own needs. Their natural instincts may cause them to gorge themselves if there’s a lot of food available, but it should be very obvious if you’re at risk of overfeeding your tarantula. Underfeeding an adult tarantula is virtually impossible if you keep offering food at least once per week.
What To Feed Tarantulas
Most tarantulas will happily go their entire lives eating nothing but insects. A tarantula’s staple diet in captivity is usually gut-loaded crickets, although a pinky mouse can be offered to larger species occasionally.
The average tarantula will only need one or two crickets each week, although as many as six may be eaten by a particularly large tarantula when it’s hungry e.g. shortly after molting. South American terrestrial tarantula species (e.g. Brazilian Salmon Pink Tarantulas Lasiodora parahybana) tend to be voracious eaters compared to other kinds of tarantula.
Spiderlings can be a little trickier to feed, but wingless fruit flies often make an ideal diet. As mentioned above, spiderlings need food more frequently than adults as they’re less resilient and grow much faster.
For adult tarantulas, feeding them just once or twice per week is fine. Some owners only offer food once every two weeks. Your tarantula will gorge itself if it needs the nutrition, and a week or two without food is no big deal to a tarantula. Just make sure you remove any uneaten food within 24 hours or so.
How Long Can A Tarantula Go Without Water?
Water is much more crucial than food when it comes to a tarantula’s short-term survival. Dehydration will of course occur more quickly in tropical species adapted to high humidity, but all tarantulas should be provided with a bowl of fresh water, ideally changed every day.
Some tarantulas (particularly desert species) will be able to gain much of the moisture they need from their food. However, they will still drink from an available freshwater source and it should always be available to them.