Methods for Sexing Tarantulas

The following is a tarantula sexing reference guide withinformation collected on the web and through personal experience.

Method #1: Exuvia (molt): Using the tarantula’s molt is the absolute best, and most definitive, way to sex your tarantula.

·  When looking at the exuvia locate the epigynum: 

If the area of the epigynum is smooth your tarantula is male.  If you locate an uterus externus and spermatheca your tarantula is a female.

 Did you know that different tarantula species have different spermatheca shapes?  Check it out (click for expanded sizes, linked to the very helpful

Spermathecae, table 8Формы сперматек.7Spermathecae, table 6Spermathecae, table 5Spermathecae, table 4Spermathecae, table 3Spermathecae, table 2Spermathecae, table 1

Method #2: Ventral: Ventral sexing refers to inspection of the underside of the tarantula, focusing on the area of the epigastric furrow (the fold between the anterior set of book lungs).

·  Females will have an opening in the furrow, called the gonoslit, sometimes resembling “lips:”

Above is a photo of the ventral side of a mature female Lasiodora parahybana.  The gonoslit in this female is very apparent.


·  Males will have a dense, circular or crescent patch of hair, known as epiandrous fusillae:

Above photo is a sub-adult male Grammostola pulchripes.

 ·  Some not-so-common and less accurate ways of ventral sexing:




Form of epigastric furrow

more curved in contrast with male

practically presents itself direct line, going between internal corners of booklungs

Distance between anterior pair of booklungs

wider apart one from another

closer located to one another in contrast with female

Angle formed lower edge of booklung to medium line of body of tarantula

booklungs more detour from horizontal line than at males, angle would be not less 20 degrees

booklungs are situated more horizontally than in males, angle would be nearly 5 degrees

Method #3: Sexual Dimorphism: Useful only at ultimate instar, mature males look vastly different than mature females.

·  All males will develop palpal bulbs, sometimes referred to as “boxing gloves” in the hobby.  These are located at the end of the male’s pedipalps.  Most males will develop tibial hooks:

Above photo is a preserved specimen of an adult male Aphonopelma hentzi.

The following tarantula genera DO NOT have tibial hooks as mature males:

Annandaliella Hirst, 1909 (Selenogyrinae)

Anoploscelus Pocock, 1897 (Eumenophorinae)

Augacephalus Gallon, 2002 (in part): A. junodi (Simon, 1904) (Harpactirinae)

Chilobrachys Karsch, 1891 (Selenocosmiinae)

Citharischius Pocock, 1900 (Eumenophorinae)

Coremiocnemis Simon, 1892 (Selenocosmiinae)

Euphrictus Hirst, 1908 (Selenogyrinae)

Heteroscodra Pocock, 1899 (Stromatopelminae)

Heterothele Karsch, 1879 (Ischnocolinae)

Hysterocrates Simon, 1892 (Eumenophorinae)

Ischnocolus Ausserer, 1871 (Ischnocolinae)

Lyrognathus Pocock, 1895 (Selenocosmiinae)

Metriopelma Becker, 1878 (Theraphosinae)

Nhandu Lucas, 1981 (in part): N. carapoensis Lucas, 1981 (Theraphosinae)

Orphnaecus Simon, 1892 (Selenocosmiinae)

Pachistopelma Pocock, 1901 (shield of spines only) (Aviculariinae)

Phlogiellus Pocock, 1897 (Selenocosmiinae)

Phoneyusa Karsch, 1884 (Eumenophorinae)

Phormingochilus Pocock, 1895 (Ornithoctoninae)

Plesiophrictus Pocock, 1899 (in part): some males may possess tibial apophyses (Ischnocolinae)

Poecilotheria Simon, 1885 (Selenocosmiinae)

Selenocosmia Ausserer, 1871 (Selenocosmiinae)

Selenotholus Hogg, 1902 (Selenocosmiinae)

Selenotypus Pocock, 1897 (Selenocosmiinae)

Sericopelma Ausserer, 1875 (Theraphosinae)

Stromatopelma Karsch, 1881 (Stromatopelminae)

Theraphosa Thorell, 1870 (in part): T. blondi (Latreille, 1804) (Theraphosinae)

Thrigmopoeus Pocock, 1899 (Thrigmopoeinae)

Xenodendrophila Gallon, 2003 (Stromatopelminae).

(From BTS Journal No. 20 (3): 81-82: "A Listing of Male Theraphosids Which Lack Tibial Apophyses" by Lucian K. Ross & Rick C. West)

Note: There are certain species that while the mature males do have tibial hooks, the hooks are rather small and may not be as noticeable as our image above.  For example: Avicularia


·  Mature females will have a stockier body than the long and leggy mature males:

Above is the stocky female Lasiodora parahybana and the leggy male Lasiodora parahybana.


·  Many species of tarantulas exhibit sexual dichromatism, meaning that upon maturity the males and female will differ in coloring:

Above example is the male and female Psalmopoeus irminia.  Notice the male is overall grayish in color while the female has retained the black and orange coloring typical in sub-adults.