Breeding tarantulas

Male & female

Firstly you must ensure that your male and female are both of the same species, both are mature and quite recently moulted. An adult female will usually moult only once a year; this is a good sign that your female is mature. If the female to be mated is to far into her moult cycle, about 6 months since the last moult, the chances are she will not produce an eggsac. You will know when your male is mature; He will show some physical changes during his maturing moult. He will usually have a smaller body, and his legs will appear long and spindly, if you look at the front two walking legs, you may see a small hook, common in most species, these are his mating hooks. He will use these hooks to hook the female's fangs during mating. Also if you look at his pedipalps, (the short legs by the mouth) on the end where there were feet, the feet will have been replaced with what look like boxing gloves. These are the bulbs where he will store his sperm.

This photo shows his bulbs where he will store his sperm

This photo shows the mating hooks on the front walking legs

Sperm web

Before he is ready to mate he will need to produce a sperm web, normally made within a couple of weeks of his maturing moult. This is usually a hammock shaped web, made in a corner of his enclosure. He will then wriggle under his sperm web, and start to rub himself against the web. This is depositing his sperm onto the sperm web. When this has been completed, he will then appear to be walking all over the web. If you look closely at his bulbs, you will see his embolus (a small pointed hook) going into the web, this is taking up the sperm from the web, which he will store until he finds a female. When he is finished with the sperm web, he will usually destroy it. He is now ready for mating.

In the photo on the left you can see a mature male Phormictopus cancerides. he has made his sperm web, (the white mass in the left of the photo) he is now under the sperm web depositing his sperm onto the web. the male is not ready for mating until this process has been completed. once he has finished this web will be destroyed


The male should always be introduced into the female's enclosure, never the other way round, he should be introduced at the opposite end to the female's position, you don't want him to just blunder into her, or it could turn nasty. Upon his arrival into her enclosure, you may observe some strange behaviour. He should start to twitch and dip his abdomen, he may also drum the substrate with his front legs and palps, all the time getting closer to the female, and she may reciprocate with some drumming of her own. When their legs first touch, he will keep tapping and rubbing her legs until she goes into a threat posture. He will then be trying to hook her fangs with his mating hooks, when he's hooked her, he will lift her up, quite surprising sometimes, when he's a lot smaller then her. He will then insert his embolus into her epigastric furrow and deposit his sperm. Now be ready to catch him, when he moves away from her, he will not be hanging about. This can all take anything from 10 seconds to hours, usually quite quick though.

The photo left shows the perfect mating of Aphonopelma bicoloratum, , contact is made. the male is trying to capture the females fang with the tibial spurs, (the hooks on the front legs) so he can lift the female sufficiently to locate the epigastric furrow. the Photo also shows the size difference between the sexes. With this pairing the male was only in with the female for around 5 minutes.
The photo on the left is of Theraphosa blondi about 4 months after she was mated, She was mated December 2002, and this photo was taken April 2003. Looking at the size of the abdomen, I would think she is certainly gravid

Eggsac production

Now the female has been mated, she should be fed well for the coming weeks, she will need all the energy she can get for egg production. All being well, over the next month or so her abdomen will begin to grow. Most species will produce an eggsac in 4 to 20 weeks; there is no absolute time scale, as there are too many variants like temperature, humidity, species etc. the signs that eggsac production is near are almost the same as an approaching moult, excessive webbing, webbing herself into the burrow, and not feeding. At this point your tarantula should not be disturbed at all, not even feeding. Hopefully she will now be holding onto her new eggsac. As long as she has the eggsac, she should not be disturbed at all, any disturbance could result in the eggsac being eaten or destroyed.

Here on the left is a photo of my Haplopelma lividum eggsac, the photo is not that clear as it was taken through the plastic pot, however you can see the size of it, it's a beauty. this spider was mated in July, the sac was not produced until the following february. Incubation was not long, I removed the eggsac after 4 weeks, at which time it contained stage 2 nymphs.

Egg development

The time for the eggsac to hatch is usually about 4 to 16 weeks, although this can vary depending on species, temperature, humidity etc. the first out of the eggsac will probably be nymphs, they look like spiders, except they are all white. this is the time we would remove, and re-house the female. the nymphs should be all left together with the eggsac until they moult into spiderlings. Depending on species the spiderlings can still be kept together for some time. But bare in mind some cannibalism may occur when they start to feed. When we separate the spiderlings, we use 35mm film pots, they are good for storing large numbers of spiderlings in a small area.

The Photo on the left shows nymphs of T. gigas as they emerge out of the eggsac, they have also had one moult in the eggsac. at this point they will not feed. they still require one more moult before they are considered to be spiderlings.