Insect Identification sample sheet

Tarantula

Nowadays, the name 'tarantula' is applied to the very large, hairy spiders that belong to the family Theraphosidae. Originally, the name was given to a much smaller wolf spider from Taranto in Italy where, in the Middle Ages, they used to dance the 'tarantella' to purge the effects of spiders' bites.

The large hairy tarantulas have also been called 'bird-eating spiders' but this Victorian term is somewhat misleading. The diet of the average tarantula consists of insects ranging from ants to large crickets and cockroaches, and small vertebrates such as lizards, frogs, mice and occasionally small snakes. Only rarely do they eat birds.

Identification

More than 600 species of tarantulas are known from tropical and subtropical regions of the world. The coloration of most is typically black or brown but some species are beautifully marked. Worthy of mention are the Poecilotheria species of southern India and Sri Lanka which have bright yellow on the first four legs; also the Haplopelma species of Thailand and Malaysia with their iridescent blue legs; and the Brachypelma species of Central America such as the Mexican red kneed tarantula (Brachypelma smithi). The Goliath tarantula (Theraphosa leblondi), from Amazonian rainforests, is thought to be the largest of all spiders. Males reach a leg span of 10 inches but, because of their light weight, eight specimens would be needed to make up a pound!

Habits

Most tarantulas live on the ground, usually in a burrow, but some dwell in holes in trees. Like other spiders, they use silk for a variety of purposes, e.g sealing leaves together, lining the burrow and making egg cocoons but in general they do not spin webs. Being clothed in sensory hairs, they can feel the slightest vibrations on the ground and in the air, but their weak eyes can discern little more than levels of light. Compared with other spiders, tarantulas are relatively primitive. For example, their fangs strike downwards like parallel pick-axes, instead of facing each other like a pair of pincers as in more highly evolved spiders.

Human relationships

The majority of tarantulas are not seriously venomous to humans but, if provoked, they may rear up on their back legs in a threat posture. In the event of a bite, and to be on the safe side, it is best to consult a doctor. One should never handle a live tarantula for, if dropped, it is likely to injure its waist or pedicel - the weak link between abdomen and cephalothorax. Furthermore, the tarantula may defend itself by rubbing off the hairs on the abdomen with its legs. These microscopically-barbed hairs can be irritating to the skin and lungs, causing a form of urticaria. The most serious damage results from hairs which become embedded in the eye.

For most tarantulas kept in containers as pets, normal room temperatures (c 70 degrees F.) should be sufficient; on no account should they be made to bask under a light bulb. A small dish of water must be provided and food should be offered weekly. Live crickets are probably the most suitable food but, if nothing else is available, live earthworms may be accepted. Female tarantulas can live for 20 to 30 years in captivity and they continue to moult about every nine months.

Contact points

This information has been produced by the Insect Information Service of the Natural History Museum. For details of our advisory and identification services, please contact:

Enquiries Manager
Insect Information Services
Department of Entomology
Natural History Museum
Cromwell Road
London, SW7 5BD
Telephone: +44 (0) 20 7942 5726

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