Giant Huntsman Spider

The Giant huntsman spider (Heteropoda maxima) is a species of huntsman spider, members of the family Sparassidae. The species is native to the Southeastern Asian country Laos. Known for its agile hunting abilities, the giant huntsman spider also holds the title of the largest known existing spider by leg span, with a leg span reaching up to one foot.

Despite likely being an old species, the giant huntsman spider was only recently discovered in 2001 by entomologist Peter Jaeger. Before their discovery, the previous largest known spider in the Sparassidae family was the Australian Beregama aurea, coming in at around 1.6 inches.

Since their discovery, entomologists have identified a number of spiders in the Sparassidae family similar in size to the giant huntsman spider, many hailing from the Greater Mekong Subregion in Southeast Asia.

Credit: WikiCommons

Huntsman spiders are often confused for tarantulas as they are large and hairy. Huntsman spiders can be distinguished by the unique orientation of their legs. While most species of spider have legs with joints oriented vertically to the thorax, the legs of the giant huntsman spider curve in front of it, almost like the legs of a crustacean (hence the huntsman spider’s nickname “crab spider”).

Anatomy/Physiology Of The Giant Huntsman Spider

Like all spidersH. maxima is composed out of a two-segmented body, a cephalothorax, and an abdomen. Typically, giant huntsman spiders are a yellowish brown color with irregular patterns and streaks of different colors on the rear. Their legs are very long compared to the rest of the spider’s body and constitute a large proportion of the spider’s size. Their legs tend to have small spines for protection while the rest of the body is hairy. Despite their overall size, their bodies are relatively flat which allows them to live in tight enclosed spaces such as in caves, under rocks, and under decaying plant material on the ground.

A giant huntsman spider baring its fangs. Credit: G. Wrigley via Flickr

Male giant huntsman spiders can be distinguished from female huntsman spiders by 2 features, the color of their legs and their external genitals. Male spiders typically have a double band of dark-colored fur on their front legs. Males have a large cymbium and tegulum, the reproductive organs of most spiders, and females have a characteristically shaped epigyneal region. Like most huntsman spiders, they have relatively large chelicerae (jaws) meant for chewing up insect and small invertebrates. Although they are venomous and have relatively large fangs, giant huntsman spiders are generally not aggressive towards humans. In the case that they do bite a human, it is non-fatal, causing only moderate pain and inflammation.

Behavior/Reproduction Of The Giant Huntsman Spider

As the name would imply, giant huntsman spiders are known for being fast and agile hunters. The use their long legs and strong jaws to pounce on unsuspecting prey, including cockroaches, crickets, silverfish, lizards, and in some cases, small birds and rodents. When they live near human settlements, they are somewhat beneficial as the feed on a number of common household pests. It has even been reported that in times of scarcity, giant huntsman spider will resort to cannibalism and eat the remains of their dead. They are able to produce silk, but as they primarily are active hunters, they do not normally produce webs to catch prey. Once it catches its prey, it injects venom into its captured prey using its longs fangs. The venom immobilizes the prey and begins to digest their body from the inside out, making it easier for the spider to consume.

Giant huntsman spiders are extremely mobile and their dextrous strong legs allow them to cling to vertical surfaces and ceilings. They are capable of jumping far distances and reportedly can move in short bursts faster than the running speed of an average human. Although they seem to be native to caves, they still have relatively well-functioning eyes, indicating that they most likely live near the entrance to caves rather than the deep recesses. Their eyesight may not be as good as something like a jumping spider, but their field of vision is wide and sharp enough to perceive an object the size of a human from 3 meters away.

Credit: WikiCommons

Unlike a number of species of spiders, huntsman spiders have been found to sometimes live together peacefully in groups of 100 or more. Unfortunately, there is presently not much information about the social structures that emerge in these colonies, but it is likely that any social structure will share similarities with those found in other species of communal spiders.

Males and females enter an elaborate and lengthy mating ritual and will remain together for some time after mating. Studies have found that male huntsman spiders will create a vibration in the ground when sensing female pheromones. This vibration acts like a message that lets females know that a viable male is in the area. To human ears, the vibrations sound like a periodic ticking sound, like a quietly ticking clock. Once a receptive female perceives the vibrations, she will find the male spider and present her genitals for copulation.

After mating, the female will lay approximately 200 eggs and wrap them in a silk cocoon for protection. She will stay there next to the eggs without eating for the entire incubation period. Generally, the incubation period is around 3 weeks but can differ based on environmental variations. During this time the female display heightened aggression and will readily attack to protect her brood. They have also sometimes been observed to periodically move the egg sac around, most likely as a means to hide their eggs from and confuse potential predators. The average lifespan of a giant hunting spider is about 10 months, but some specimens have been observed to survive up to 2 years.

In summation, giant huntsman spiders are notable for being the largest known extant species of spider. They are native to the Southeast Asian country of Laos and are predominantly cave-dwellers. They are extremely quick and agile, and can even run straight up vertical surfaces. They are active hunters and do not use webs to capture prey. A surprisingly social species of spider mated pairs will stick together for sometime after mating and they have been observed to coexist in groups of 100 or more. They are generally non-aggressive towards humans, and can sometimes be beneficial by keeping populations of common household pests in check.

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