Instructions
Consider the age of the tarantula. Female tarantulas live far longer than male tarantulas. For example, male pinktoe tarantulas live for a maximum of four years, while females may live for 12 years or longer. So, if you have a spider that has outlived the maximum age for males of that species, chances are the tarantula is a female.
Evaluate the size of the full-grown tarantula. Male tarantulas are usually much smaller than female tarantulas. Males also tend to have slimmer bodies and longer legs, while females appear stocky and larger overall.
Look at the first set of legs on the tarantula. Male tarantulas have hooks projecting from the backs of these legs. The hooks are used to fend off the female's fangs during mating. Female tarantulas lack these hooks.
Look at the tarantula's pedipalps. The pedipalps are long protrusions, somewhat like mandibles, that jut from the mouth area of the spider. Male tarantulas, after their final molt, develop large bulbs at the ends of their pedipalps. Females never develop these bulbs.
Research what mature tarantulas of the specific species you have look like. In some tarantula species, males may develop different colors or patterns as they mature that separate them from the females of that species.
Pick up the tarantula and carefully flip it over. Look at the underside of the tarantula, where the upper and lower abdomen areas meet. Male spiders have an extra set of spinnerets or fusilla. These appear as tiny hairs that grow in an arch or circular shape in this area. The fusilla are usually darker than the surrounding hair. Although the fusilla are often visible to the naked eye, a bright light or magnifying glass may be needed to see them on smaller tarantulas, or tarantulas that are lighter in color.
How to Tell a Tarantula's Gender
Tarantulas are large spiders that come from all over the world and make interesting pets. Although they don't enjoy being held or pet, observing the tarantula as it roams its habitat can be fascinating. Many people may want to know more about their pet, and wonder whether it's a male or female. Others may want to breed their tarantulas. Captive-bred tarantulas are often much more docile than wild-caught tarantulas. There are many different types of tarantulas, but all have similar gender markers. Some are more apparent than others, however, and sexing your pet tarantula will take careful examination and research.