Huntsman Spiders, Sparassidae

Sparassidae is a family that holds over one thousand species of huntsman spiders, also known as giant crab spiders and wood spiders, or as rain spiders or lizard-eating spiders in some areas of its range. These species are native to Australia but were also introduced to temperate areas throughout the world including China, Japan, and some areas of the United States, including Florida and Hawaii. They inhabit warmer areas and can often be seen entering human habitations and other shelters before rains in Africa. Adult members of this family do not build webs, as they are large and strong enough to hunt, and most species reside in sheltered areas like under bark and rocks and in human shelters like garages and sheds.

Many species within the Sparassidae family grow to be very large, with some males of the species Heteropoda maxima growing to a size between ten and twelve inches in leg span. Many confuse members of this family with tarantulas, but the two are not closely related. Huntsman spiders can be easily identified by their legs, which are long and sometimes twisted in such a way that they resemble crab legs. The dorsal surfaces of huntsman spiders are typically brown to grey in color with no distinct markings, while the underside can hold black and white markings and the mouth a reddish coloration. The legs often hold distinct spines, but the rest of the body is hairy.

Although the eyesight of huntsman spiders is not excellent, it is still adequate enough for them to detect prey and threats from a moderate distance.  Males from the Heteropoda venatoria species, one of the most common in the world, are able to produce a sound, once they have found the scent left behind from a potential mate, which is produced by vibrations throughout the male’s body. Females can recognize the species of spider that is producing this sound by its frequency and vibration and then approach the male if they are interested in mating.

Most members of this family use venom to restrict the movement of their prey before consuming it, and although they will bite humans to protect themselves, these bites are not known to be dangerous. Some studies have shown that these bites can result in mild symptoms such as swelling or moderate pain, while other suggest that they can cause nausea or more serious issues like heart palpitations and vomiting. However, formal studies are difficult to conduct for many reasons, including secondary infections and nocebo effects. Typically, bites from huntsman spiders do not require hospitalization.

Image Caption: A mature female Palystes castaneus (rain spider). Credit: JonRichfield/Wikipedia (CC BY-SA 3.0)