Male tarantulas can be identified by the presence of so-called palpal bulbs - swellings looking rather like a pair of miniature boxing gloves located on stalks near to the mouth. You may need to look at your spider quite closely to spot them, so persuade it to walk into a clear plastic container with a lid for this purpose. Alternatively, wait until it moults again, and study the cast-off skin, when the palpal bulbs should be obvious if they are present.



In some species, there may be other easier means of determining an individual's gender. Mature male Costa Rican zebra tarantulas (Aphonopelma seemani) are black for example, lacking the zebra-like stripes present on the legs of the female, as seen here on the picture.