Many newcomers to the hobby wonder if one sex is known for having a better disposition. This typically leads them to ask whether they should get a male or a female tarantula.
Casual keepers who don’t plan on having many specimens may be better suited for female tarantulas because they are long-lived and typically showier due to their larger size and better coloration. Males only live a short time after maturing, and after their final molt, they rarely eat and tend to pace the enclosure endlessly. In general, mature males tend to be more skittish and prone to bolting when they are startled.
Why do hobbyists want female tarantulas?
If you have spent any time on invertebrate forums, then you’ve probably noticed a trend. Keepers seem to only want to end up with females. Therefore, many people will purchase multiple slings of the same species to up their odds of getting a female specimen.
But why is that? Does that mean that males make unsuitable pets? Not at all. Male tarantulas make perfectly good pets, and they look identical to the females outwardly until their maturing molt.
Hobbyists want female tarantulas typically because they have a longer life expectancy than males. Mature males only live for approximately a year or so after their final molt, which can be difficult to deal with when you have raised something from a tiny baby.
Adult size is another reason why people prefer females. Females of all species are generally larger and more heavy-bodied than males. Apart from some Pamphobeteus species, and probably a few others that I’m forgetting, female specimens usually have better coloration as adults.
A good example of this is P. irminia. Once mature, the females sport a stunning black color with orange markings on their legs and abdomen. The males of this species do not show the beautiful colors the females have. Instead, male P. irminia specimens are super fluffy and grey once they mature. Interesting in their own right, but nothing special compared to a velvety orange and black female. Until maturity, both sexes look the same, though.
Some hobbyists prefer to have female specimens because they are a better return on investment. Aside from being bred, a female tarantula can also be sold for a higher price than a male.
What can I do if my tarantula turns out to be a male?
If you were really hoping for a female, but your tarantula turned out to be male, then don’t feel gutted! You can still offer him to someone that breeds tarantulas on a breeding loan. Usually in an arrangement like this the owner of the male will get some of the slings as a trade if the paring is successful, which means you can try again for a female.
If you would rather keep your male for the rest of his days, then it’s advisable to move him into a smaller enclosure. This will prevent him from exhausting himself prematurely while he roams the cage looking for a mate.
How do you tell if a tarantula is a boy or a girl?
The most reliable way to determine the sex of your tarantula is by inspecting their old exuvia after molting. Female tarantulas will exhibit spermathecae and a uterus externus. To find evidence of these reproductive organs, you have to look on the inside of the exuvia which is why this method cannot be done on the actual spider.
It’s a good idea to check out examples of the type of spermathecae you are looking for before attempting this as some species can be tricky. The males of some species have accessory organs that resemble spermathecae closely.
If your tarantula is quick to shred their molts, then you can still try to determine if they are male or female once they reach approximately 2 inches by using a method called ventral sexing. Small slings cannot be ventral sexed.
Ventral sexing is not a foolproof method, but some hobbyists are pretty good at guessing. It’s always a good idea to molt confirm a specimen as soon as the opportunity presents itself.
When you are ventral sexing a tarantula, you are looking for the epigastric furrow, which is located between the top set of book lungs on the underside of the spider. Females tend to have a curved, very pronounced looking epigastric furrow.
In addition to examining how pronounced the furrow is, hobbyists also use the spacing and angle of the book lungs to guess the sex. While attempting to ventral sex, you can also check for epiandrous fusillae, which looks like a dark patch of hair on most species. Only the males have epiandrous fusillae.
If you don’t want to use either of those methods, then you will just have to wait. Many tarantula species display sexual dimorphism at maturity. This means that the females look different from the males.
The males of most species will hook out once they molt into mature specimens. You will be able to see small hooks on their front legs. These are called tibial spurs, and they are intended for holding the female’s fangs. Mature females never have tibial hooks.
Mature males of all tarantula species will have pronounced “boxing gloves” at the end of their pedipalps. This is where they store the sperm. At the end of each pedipalp there is a small teardrop shaped bulb that ends in a hook. This hook is what transfers the sperm packet to the female.
Are female tarantulas bigger than males?
Females of all tarantula species are bulkier than their male counterparts, but not necessarily larger in leg span (although this is common, too). Once the male goes through their ultimate molt, they are leggier and spindlier looking than females.
Are male tarantulas more defensive than females?
Both male and female tarantulas have the ability to become defensive, and both sexes will readily adopt a threat pose if they are startled or provoked. There is not an overwhelming difference between the way male and female tarantulas behave until after the male’s maturing molt. Mature males tend to act more skittish and they seem to be more willing to bolt out of their enclosure at the slightest disturbance.
Are male tarantulas better than females to hold?
Neither males or females are more suited for handling. Both sexes can bite without warning or bolt quickly off of your hands. A fall like this can fatally injure the spider. I personally treat my tarantulas as “look but don’t touch” pets.
Is there a difference in male vs. female chelicerae size in tarantulas?
Mature males often have smaller looking chelicerae. A good example of this Aphonopelma chalcodes, which is native to my state. Next to a female specimen, the male’s body and chelicerae look much smaller.
Although the mature male A. chalcodes has approximately the same leg span as the mature females, their body looks disproportionate when compared to how leggy they are.
Can tarantulas change gender?
No, tarantulas cannot spontaneously change their sex. Although some new hobbyists may be under the false impression that they can because they were sold a “female” specimen that later hooked out as a male.
Can tarantulas reproduce by parthenogenesis?
It’s possible that there may be an undiscovered parthenogenic species that can lay a viable egg sac without a male. However, there haven’t been any found yet.
Female tarantulas can retain sperm for a year, or until they molt again, whichever comes sooner. This can sometimes make it seem like they are laying an egg sac without male intervention.
Are tarantulas a hermaphroditic animal?
Tarantulas can be gynandromorphs, which means they have both male and female sexual organs while displaying sexual dimorphism, as well. Hermaphroditic and gynandromorphic organisms are two different things in reference to animals.
Gynandromorph specimens happen rarely in the tarantula world, but they are possible. When a tarantula displays characteristics of both sexes, the body appears to be cut down the middle vertically. One side will have male characteristics, and one half will be female.
Unfortunately, these specimens usually don’t live long past the ultimate molt for the male side. Mature males tend to have molting problems due to the shape of their pedipalps. A molting issue like this will kill the whole specimen.
Final Thoughts on Getting a Male vs. Female Tarantula
I personally always gravitate towards having females because I’m not currently trying to breed many specimens in my collection and I want my tarantulas to live as long as possible. There’s just something really special about a giant spider that you get to see every day for a decade or more!
Because of this, tend to buy slings in multiples of three or five to make sure I at least get one girl – I sell or trade the males once I definitely molt sex them as long as I’m not planning on breeding that species.
That being said, if you don’t have room for large invert collection don’t let the male versus female debate sway you from keeping a tarantula or two as a pet – watching a spiderling grow is just as rewarding regardless of which sex you get. Males look identical to the females while they are immature, and you will still get years of enjoyment out of watching them.