Tarantulas, fascinating arachnids belonging to the Theraphosidae family, are known for their impressive size and diverse appearance. A common question revolves around identifying the largest of these creatures.
The World’s Largest Tarantula
The Goliath Birdeater (Theraphosa blondi) is the world’s largest tarantula by mass. This species hails from the rainforests of northern South America, inhabiting regions such as Suriname, Guyana, French Guiana, northern Brazil, eastern Colombia, and southern Venezuela. These terrestrial spiders are often found in deep burrows within marshy or swampy areas.
They can reach a leg span of up to 12 inches (30.5 cm) and weigh over 6 ounces (170 grams). Their bodies are tan to light brown with golden hues, covered in short hairs. Despite their name, which originated from an 18th-century engraving of a tarantula eating a hummingbird, they rarely prey on birds. Their diet primarily consists of large arthropods, worms, amphibians, and small terrestrial vertebrates.
Goliath Birdeaters possess fangs large enough to pierce human skin, measuring up to 1.57 inches (4 cm). Their venom is considered relatively mild, comparable to a bee sting, and is not lethal to humans. When threatened, they produce a hissing sound by rubbing bristles on their legs, a behavior known as stridulation. They also defend themselves by flicking urticating hairs from their abdomen, which can cause irritation to skin and mucous membranes.
How Bigness is Measured
Measuring a tarantula’s size primarily uses the diagonal leg span (DLS). This is the most common and widely accepted measurement. DLS is taken from the tip of the front leg to the tip of the opposing hind leg, with the legs stretched out. This method provides a clear indication of the spider’s overall reach.
Body length is another metric, measured from the front of the cephalothorax to the tip of the abdomen, excluding the spinnerets and chelicerae. This measurement can be more consistent but does not convey the full size that includes leg span. Weight is also considered, particularly for species like the Goliath Birdeater, which holds the record for mass. While body length and weight provide valuable data, leg span is generally preferred for tarantulas as it best represents their sprawling size.
Beyond the Biggest: Other Large Tarantulas
While Theraphosa blondi holds the title for mass, other tarantula species also reach impressive sizes. The Pinkfoot Goliath Birdeater (Theraphosa apophysis) rivals the Goliath Birdeater in leg span, with females reaching over 10 inches (25 cm). This species, found in Venezuela, Colombia, and Brazil, is known for the pink coloration on its feet, which gradually fades with each molt.
Another notable giant is the Burgundy Goliath Birdeater (Theraphosa stirmi), native to Guyana and Brazil. Females of this species can also achieve leg spans of 10 to 12 inches (25 to 30 cm), making them comparable in size to Theraphosa blondi. The Brazilian Salmon Pink Birdeater (Lasiodora parahybana) is another contender, with adults capable of reaching a diagonal leg span of approximately 10 inches (25 cm). This species, indigenous to Brazil, is recognized for its robust build and salmon-pink hairs on its abdomen. While these species are undeniably large and imposing, they do not typically surpass the record-breaking weight of the Theraphosa blondi.