Species, growth, gender

The different types of tarantulas

By habitat type

Ground dwellers

These tarantulas live on the ground, often in shallow burrows that they dig themselves.

Tree dwellers

These species are adapted to life in trees and build their shelters in bark crevices or among leaves.

Underground dwellers

These tarantulas specialize in living underground and dig deep burrows.

It is important to note that some species adopt an intermediate lifestyle and can inhabit different types of habitats.

By geographical origin

New World

These tarantulas often have urticating hairs that they can shoot out when threatened. Their venom is generally no more dangerous than that of a wasp.

Old World

These tarantulas often do not have urticating hairs, but are generally considered to be highly venomous (though not lethal) and are faster than their Old World counterparts.

This is a global classification with exceptions, so be sure to check with your breeder or other experts about the specifics of the species you are adopting.

Growth

The growth rate of tarantulas depends on several factors: species, temperature, feeding frequency. The size of tarantulas varies within the species due to genetic factors.

The various life stages of a tarantula

The life cycle of a tarantula can be divided into three main phases, each characterized by specific morphological and behavioral characteristics:

Sling

At birth and in the following months, the tarantula is referred to as a “sling.” It is very small (less than 3 cm in body length with legs) and often has weaker coloring and different patterns than adult animals. This stage is the fastest growing.

Juvenile

Once the tarantulas have grown, they enter the juvenile phase. At this stage, the tarantula already looks like a miniature version of the adult, although its colors and patterns may still change.

Adult

Adulthood is reached after the last significant molt. At this stage, the final coloration and patterns appear, which are often gender-specific. Later molts are less frequent, result in less growth, and mainly serve to renew the exoskeleton.

A sling of an unknown species

An adult Brachypelma Hamorii

Male/female differences

The differences between males and females only become apparent in adulthood. Males are distinguished by copulatory bulbs, known as bulbs, on their pedipalps and hooks on their front legs. Some species exhibit pronounced sexual dimorphism (different colors and shapes). Males are often slimmer with longer legs, while females are more robust. Lifespan varies greatly: males live for around 3 to 10 years, females for 10 to 30 years.

Embolus, present on all pedipalps of all males.

Tibial hooks, present on the legs of male for some species.

Tarantula numbering:
a simple code to understand everything.

To facilitate the identification and tracking of individuals, breeders use a special numbering system. This system is as follows: A.B.C

A corresponds to the number of male animals.
B corresponds to the number of female animals.
C corresponds to the number of individuals whose sex has not yet been determined.

Examples:

0.1 means that you have a female.
1.0 means that you have a male.
0.0.1 means that you have an individual whose sex has not yet been determined with certainty (often a sling or juvenile).

Determining the gender of a tarantula

The sex of a tarantula can be determined before it reaches adulthood by examining its molted skin. A spermatheca inside the exuvia between the abdominal lungs indicates a female. You can soak the skin in water with a drop of dish soap to soften it, and then, depending on the size of the skin, look for this flap with a magnifying glass or microscope (the shape of the flap varies from species to species). For more accurate identification, you can also post a photo on special forums such as Arachnoboard to get the opinions of other breeders.

1. Spermathecae

2. Abdominal lungs