While some species of tarantula grow far faster than others it is possible within reason to control just how quickly individual tarantulas grow in captivity.
There are a number of reasons why it can be helpful to understand the concepts of making your tarantulas grow faster or slower. The first of these is that buying tarantula spiderlings is often far cheaper than buying larger grown on tarantulas so one way to save money is to buy youngsters and then encourage them to grow as quickly as possible.
Another reason why understanding how to control the growth rates of tarantulas can be handy is when it comes to breeding tarantulas. When an adult female tarantula goes through her annual moult she also moults out the inside of her reproductive organs and becomes virgin again. In this way if you try to mate a female tarantula too close to a moult she may change her skin before laying eggs and thus your breeding attempts will come to nothing.
Equally adult males may only live for a few months and may not even be fertile for the whole of that short period. Therefore controlling growth rates of tarantulas gives you the best possible chance of ensuring that you have a freshly-moulted adult pair ready to mate.
The Two Main Factors Affecting Tarantula Growth Rates
The two main controlling factors on how fast your tarantula will grow are temperature and food intake. At a basic level the warmer you keep your pets and the more food you give them the faster they will grow.
Of course it’s not as simple as just ramping up the heat on your tarantulas and filling their cages with crickets every day and hoping everything goes according to plan. Firstly a tarantula can die if it overheats and secondly excess livefood can stress a tarantula out or even lead to injury if a tarantula tries to moult in the presence of crickets.
The key is therefore to keep careful records and to pay close attention to your spiders on a regular basis.
Firstly pay attention to where your tarantula typically rests in it’s cage in relation to the heat gradient. If it’s always found at the cooler end then the cage may be too warm. If it is found regularly at the warm end then you might like to consider trying to increase the temperature of the cage while paying careful attention to how your spider reacts.
However feeding is where you can get the easiest wins. As an experiment many years ago I took 100 spiderlings and fed half the group twice as much as the other half over several months to see how this affected their growth.
All the spiderlings remained healthy over this period. None were “starved” – I simply fed one half more often than the other half.
The end result after months of record-keeping was that feeding my spiderlings twice as much led them to grow around 20% faster than those being fed the standard amount of livefood.
Again though if you’re trying to feed up a tarantula ensure you remove any uneaten livefood within 24 hours of introduction and try to keep records so you know exactly how often – and how much – your individual spiders will eat so they can grow as quickly as possible without having unwanted livefood hanging around the cage on a regular basis.