Spiders, with their diverse forms and behaviors, have long captured human curiosity, sometimes mixed with apprehension. Their sheer variety is remarkable, ranging from tiny species to imposing arachnids that can span the size of a dinner plate. This wide spectrum of dimensions often leads to fascination about which species holds the title for the “longest” in the world.
How Length is Measured
Determining the “longest” spider requires understanding how these creatures are measured. Two primary metrics are used: leg span and body length. Leg span, often referred to as Diagonal Leg Span (DLS), measures the distance from the tip of the first leg on one side to the tip of the fourth leg on the opposite side, assuming the spider is fully stretched. This measurement provides a representation of a spider’s overall reach and is frequently used when discussing large tarantulas.
Body length, in contrast, is a more precise scientific measurement. It is taken from the front of the spider’s carapace (head and thorax) to the rear of its opisthosoma (abdomen), excluding the spinnerets. While body length offers a more consistent measure for scientific classification, it can still vary slightly depending on factors like the spider’s recent feeding or hydration status. Both measurements are important for a complete understanding of a spider’s size, with leg span often capturing public imagination and body length providing detailed biological data.
The World’s Longest Spiders
The title for the world’s longest spider depends on the measurement method used. The Giant Huntsman Spider, Heteropoda maxima, holds the record for the longest leg span. This species can reach up to 30 centimeters (12 inches), roughly the size of a dinner plate. Its body, however, is comparatively smaller, measuring around 4.6 centimeters (1.8 inches).
The Giant Huntsman Spider is native to Laos, in Southeast Asia, and is primarily found in limestone caves. Its yellowish-brown coloration and legs with wide dark bands help it blend into its environment. Unlike many other spiders, the Giant Huntsman does not build webs to catch prey; instead, it actively hunts, relying on its speed and agility.
In terms of mass and body length, the Goliath Birdeater, Theraphosa blondi, is recognized as the largest spider. It can weigh up to 175 grams (6.2 ounces) and have a body length of up to 13 centimeters (5.1 inches). While its leg span can also reach up to 30 centimeters (12 inches), it is typically slightly less than the Giant Huntsman’s. The Goliath Birdeater is native to the rainforests of northern South America, including Suriname, Guyana, and Brazil. It has a hairy body that ranges from dark to light brown, often with a golden hue.
Other Notable Large Spiders
Beyond the record holders, several other spider species are notable for their considerable size. The Brazilian Salmon Pink Birdeater, Lasiodora parahybana, is a prominent example among the largest tarantulas. This species can achieve a leg span of up to 25-28 centimeters (10-11 inches), though many individuals typically measure between 8 and 9 inches. Its body length is approximately 4 inches.
Native to the humid, dense forests of eastern Brazil, the Brazilian Salmon Pink Birdeater is recognized by its distinctive salmon-pink hairs, which become more pronounced as the spider matures. Another impressive tarantula is the Colombian Giant Tarantula, Megaphobema robustum, also known as the Colombian Giant Redleg. This species can have a leg span of around 20 centimeters (7 inches) and is found in the tropical rainforests of Colombia and Brazil. The Brazilian Giant Tawny Red Tarantula, Grammostola mollicoma, is yet another large species, with a leg span that can approach 25 centimeters (10 inches), inhabiting the grasslands and forests of southern Brazil.
Habitat and Behavior of Giant Spiders
Giant spiders inhabit a variety of warm climates across the globe, adapting to diverse ecosystems such as rainforests, caves, and other terrestrial environments. The Giant Huntsman Spider, for instance, thrives in the dark, warm conditions of limestone caves, often near their entrances, in Laos. In contrast, the Goliath Birdeater prefers the humid, swampy rainforests of northern South America, where it resides in deep burrows. The Brazilian Salmon Pink Birdeater is also terrestrial, found in the humid forests of northeastern Brazil.
Most of these large spiders are nocturnal, meaning they are most active during the night. Their hunting strategies vary; the Giant Huntsman is an active predator that pursues its prey with remarkable speed, while the Goliath Birdeater is an ambush predator, relying on vibrations to detect its next meal. While their diet primarily consists of insects, these larger species are capable of preying on small vertebrates such as frogs, lizards, rodents, and occasionally even birds or snakes.
For defense, many large tarantulas, including the Goliath Birdeater and the Brazilian Salmon Pink Birdeater, possess urticating hairs on their abdomens which they can flick at perceived threats, causing irritation. The Goliath Birdeater can also produce a hissing sound by rubbing its bristles together and may rear up to display its fangs as a warning. Despite their intimidating size, the venom of most large spiders is not considered dangerous to humans; it is primarily designed to subdue their small prey. Bites typically result in mild, localized symptoms such as pain, swelling, or redness, often comparable to a bee sting. Fatalities from spider bites are exceedingly rare.