Tarantulas

Family: Theraphosidae

Description: There are currently seven tarantula species described in Australia from four genera, Selenocosmia, Selenotholus, Selenotypus, and Phlogiellus, with six species occurring in Queensland. Tarantulas range widely in size with a leg spans between 5 to 16cm. Females are usually larger than males. In general, tarantulas have a large, heavy body, which varies in colour from dark chocolate-brown to pale fawn. As there are many species yet to be described, it can be very difficult to identify some spiders.

Tarantulas in Australia have often been called whistling, barking or bird-eating spiders because of the sounds most species can make. The whistling noise is most often produced when the spider is disturbed and takes up a threatening defensive pose. This may act as a deterrent against predators.

Habitat and distribution

Tarantulas from the Genus Selenocosmia are known from Queensland, New South Wales, South Australia and Western Australia. They occupy many habitats ranging from rainforest to desert but are not found in the southern coastal areas or northern tropics. Selenotypus are found in the Northern Territory and Selenotholus are found in north-western Queensland.

Life history

Adult female tarantulas have a life-span of up to 12 years and live in web-lined burrows in the ground. Burrows can be quite deep from 40–60cm, and the width usually varies depending on the size of the spider. Some burrows may have a thin film of web around or across the entrance. The temperature of the burrow remains fairly constant, except in the warmer months from September to May. Younger individuals and males, which are smaller than females, tend not to use burrows and are usually found in silk retreats under rocks and/or logs.

During spring and early summer, males search for females hidden in their burrows and entice them out to mate at the burrow entrance. Several days after mating, the female lays about 50 eggs into a 3cm diameter sac, which is stored in the burrow and protected by a tough cover of silk. Juveniles have their first moult in the sac, then leave the sac and moult a second time before leaving the burrow as free-living individuals. Males stop moulting once they reach sexual maturity while females continue to moult throughout their life. Adult males can be distinguished by their swollen palps (the pair of front sensory/mating organs).

Although tarantulas are often referred to as 'bird-eating spiders' they rarely eat birds. They are nocturnal, generalist feeders and their most common prey items are insects, lizards, frogs, and other spiders. Small hatchlings may be taken occasionally from nests on the ground.

Australian tarantulas are large spiders and can be much more aggressive than their South American relatives. If disturbed, individuals may 'rear up' and appear rather menacing. The bite is painful, as the fangs are large and can grow up to one centimetre long. Severe illness sometimes results, and nausea and vomiting for six to eight hours have been reported from bites. These large spiders should not be handled. If someone is bitten, seek medical attention and collect the spider for positive identification.

Threatening processes

It is estimated that 10,000 tarantulas are taken from the wild, mostly in Queensland every year to be sold as pets across Australia, which may have a negative impact on populations. By removing the large adults from small local populations, collectors could be threatening species that have limited distributions, and that may not yet have been properly studied or described.

How can you help?

You can help conserve Queensland's tarantulas by:

• being aware that some pet spiders have originated from the wild
• discourage the collecting of tarantulas (or other animals) from the wild, as this threatens wild populations
• do your bit to help protect habitats that are known to contain tarantulas.