How Do Tarantulas Mate?

Mexican Red-Knee tarantulas mating.
Tarantulas only mate about once a year.

Getty Images/skydie

There are around 850 different species of tarantulas, and several of them have found their way into the hearts and homes of pet owners. After falling in love with one tarantula, spider owners may decide that they want more than one pet spider and decide to breed them. Knowing more about how pet tarantulas mate can help a tarantula owner provide the best possible care to their current and future spider family.

Can You House Tarantulas Together to Mate?

It is not recommended to house a male and female tarantula together because they are normally cannibalistic. When both tarantulas are sexually mature, you can place the male in a small enclosure inside the female's enclosure for a few days or a week. This will allow the tarantulas to see and smell each other without causing harm to one another. During this time, the female should create a burrow and be fed so that she is not hungry when she meets the male. The tarantulas should only be allowed together if the female is receptive to the male and then once the mating occurs, the male should be removed from the enclosure before the female becomes aggressive towards him.

A paint stick is a good tool to have to break up a fight or assist in removing the male from the female's enclosure. If your tarantulas are not interested in mating, do not attempt to force it or continue to house them together. Tarantulas should be housed by themselves.

When Is a Tarantula Ready to Mate?

When a male tarantula is sexually mature, they are able to produce semen and breed with a sexually mature female. The age of sexual maturity in a tarantula will vary between species but may not occur until they are several years of age. Once a male tarantula reaches maturity, they also don't usually live for more than a year or so. This means that the amount of time you have to breed your male tarantula is limited.

Reproductive Habits of Tarantulas

Mating usuallly occurs once a year, but how a tarantula mates is probably not what you would expect. Once a male tarantula is mature and wanting to mate, he will rub his abdomen onto a web mat that he wove. This rubbing will excrete semen which the male will then rub onto his pedipalps, i.e. fangs, into a little packet. The pedipalps keep the semen viable in the little packet until he can find a female to mate with. When a suitable female is found, the semen packet from the pedipalps is inserted into an opening called the opisthosoma in the female's abdomen. The male will then quickly leave before the female is no longer welcoming of his presence for mating purposes.

Laying Eggs

Depending on the species of tarantula, eggs will be fertilized and laid several weeks or months after this mating occurs. These eggs will be laid inside an egg sac that will be produced by the female tarantula. This egg sac will then be carefully cared for and rotated by the female tarantula in her burrow until the babies emerge from the sac. Aggression is typical from the female tarantula while she is protecting this egg sac.

Some tarantula breeders opt to take the eggs away from the mother spider when the egg sac is produced to prevent her from eating her young when they hatch and to make it easier to separate them as they grow. These eggs would then need to be kept warm in another enclosure, but you can also attempt to keep them with the mother spider until they go through their first molt.

How Many Babies Do Tarantulas Have?

The number of eggs that a tarantula will lay varies between species but around 100 eggs is a good amount to expect from most pet tarantulas. Some species only lay around 50 eggs while others lay over 1,000 eggs, so breeding tarantulas is not a hobby for someone who simply wants one or two more spiders to care for.

In the case of the Mexican Red-Knee tarantula, fertilized eggs hatch inside the egg sac after about three months and then around 200-400 babies may appear from the sac after another three weeks. These spiderlings will go through several molts during their first year of life and the number that survive to adulthood will depend on how well you care for them.