Biggest Spider in the World – Heaviest vs Longest Leg Span Compared

Ask any arachnologist which spider is the biggest in the world and the answer will depend on whether you are measuring by weight, leg span, or body length. Two very different creatures — the Goliath birdeater and the giant huntsman spider — each hold distinct records, making the question more layered than it first appears.

The Goliath birdeater (Theraphosa blondi), native to the rainforests of northern South America, is the heaviest spider ever found. The giant huntsman spider (Heteropoda maxima), discovered in the caves of Laos, stretches its legs further than any other known arachnid. Neither species poses a serious threat to humans, but their sizes have fascinated scientists and the public alike for decades.

This article compares the two record holders side by side, ranks the top ten largest spiders, examines how dangerous they really are, and clarifies what remains uncertain about these remarkable creatures. All facts are drawn from authoritative sources including the Natural History Museum in London, Discover Wildlife, and the World Spider Catalog.

What Is the Biggest Spider in the World?

The answer depends entirely on the metric used. No single species holds all size records. The Goliath birdeater dominates by body mass and body length, while the giant huntsman spider claims the longest leg span. Understanding which spider is “biggest” requires looking at each measurement separately. For a deeper dive into the data, see the Comprehensive Research: Largest Spiders in the World.

Key insights on the world’s largest spiders:

• The Goliath birdeater is the heaviest spider in the world, weighing up to 175g.
• The giant huntsman spider holds the record for the largest leg span at 30 cm (1 ft).
• Both species are largely harmless to humans — their venom is mild and rarely causes serious reactions.
• The ‘largest spider’ record depends on the metric used: weight vs leg span. No single species holds both records.
• The largest spider ever found alive was a Goliath birdeater with a 28 cm leg span (11 inches).
• Fossil records show prehistoric spiders were far larger (e.g., Megarachne), but these are extinct.

Goliath Birdeater vs Giant Huntsman: Which Is Bigger?

The two species are often compared directly, but they differ in almost every dimension. Here is how they stack up across the three main size metrics.

By leg span: Giant huntsman wins

The giant huntsman spider reaches a leg span of up to 30 cm (12 inches), edging out the Goliath birdeater which maxes out at 28–30 cm (11 inches). The huntsman’s long, crab-like legs with twisted joints give it the edge, though the difference is small.

By body mass and body length: Goliath birdeater wins

The Goliath birdeater weighs up to 175g and has a body length of 13 cm (4.75 inches). The giant huntsman, by contrast, has a body length of only about 1.8 inches and weighs roughly 167g. The birdeater is the heavier, bulkier animal by a clear margin.

Why the metric matters

As one source puts it, saying the giant huntsman is bigger because of its leg span is like saying a lion’s mane jellyfish is bigger than a lion. The comparison only makes sense once you specify what you are measuring. Both spiders are giants in their own right, but they hold different crowns.

Has the Biggest Spider in the World Been Found Dead or Alive?

Yes, record-sized specimens have been documented both alive and dead, though the distinction is important for verifying measurements. A living spider can be measured accurately; a dead specimen may be stretched or compressed, leading to possible errors.

Largest specimen found alive

In 2014, a Goliath birdeater with a leg span of 28 cm (11 inches) was verified as the largest alive specimen. This individual was found in the rainforests of northern South America and remains the heaviest spider ever documented alive.

Largest specimen ever recorded

The giant huntsman spider was first described in 2001 after being discovered in the caves of Laos. Its leg span of 30 cm (12 inches) has not been surpassed by any living spider since. No larger individual has been confirmed as of 2025.

Prehistoric giants

Fossil evidence shows that prehistoric spiders were far larger. Megarachne, which lived during the Carboniferous period, had a body length of about 54 cm (21 inches). These extinct arachnids are not part of modern records but demonstrate that size has changed dramatically over evolutionary time.

Is the World’s Largest Spider Dangerous to Humans?

Neither the Goliath birdeater nor the giant huntsman spider is dangerous to humans in the sense of causing serious injury or death. Both are venomous — not poisonous — and their venom is relatively mild.

Goliath birdeater venom

The Goliath birdeater delivers a venomous bite comparable to a wasp sting. The greater threat comes from its barbed hairs, which it releases as a defense mechanism. These hairs can lodge in the skin and eyes, causing itching and irritation that can last for days.

Giant huntsman spider venom

The giant huntsman spider is also venomous, and its bite may require medical intervention. However, fatalities have not been recorded. The spider is quick to flee rather than attack, and bites typically occur only when the animal is provoked.

Poisonous vs venomous: a key clarification

A common point of confusion is the difference between poisonous and venomous. Poisonous organisms release toxins when touched or eaten. Venomous organisms inject toxins through a bite or sting. Both the Goliath birdeater and the giant huntsman are venomous, not poisonous.

Top 10 Biggest Spiders in the World: Full Ranking

Beyond the two record holders, several other species rank among the world’s largest spiders. The following list is based on leg span, the most commonly used metric for comparison.

1. Giant huntsman spider (Heteropoda maxima) — Leg span up to 30 cm (12 in). Native to Laos.
2. Goliath birdeater (Theraphosa blondi) — Leg span up to 28–30 cm (11 in). Native to northern South America.
3. Brazilian salmon pink birdeater (Lasiodora parahybana) — Leg span up to 11 in (typically 7–10 in). Native to eastern Brazil.
4. Chaco golden-knee tarantula — Size comparable to other top tarantulas. Males have longer legs; females have larger bodies.
5. Sand-dwelling huntsman spider (Cerbalus aravaensis) — Leg span up to 14 cm (5.5 in). Native to sand dunes of Israel and Jordan.

Additional large species include the Colombian giant tarantula, the Brazilian wandering spider, and the giant baboon spider. The wolf spider, while well-known, is much smaller than the Goliath birdeater, with a body length of only about 3 cm.

What Is the Timeline of Largest Spider Discoveries?

The history of documenting the world’s largest spiders spans more than two centuries. Key events include the first scientific description and the discovery of the current leg-span champion. For a detailed comparison of all record holders, refer to the Largest Spiders in the World — Detailed Comparison.

1. 1804 — Goliath birdeater first described by French naturalist Pierre André Latreille.
2. 2001 — Giant huntsman spider (Heteropoda maxima) discovered in Laos, taking the leg-span record.
3. 2014 — A Goliath birdeater with 28 cm leg span verified as largest alive specimen.
4. 2024 — Reddit discussion highlights the largest birdeater ever found (28 cm leg span).
5. 2025 — Ongoing research into possible new large spider species in remote regions.

What Is Known and What Remains Uncertain About the World’s Largest Spiders?

While much is well-documented, several questions remain open. The table below separates established facts from areas where knowledge is incomplete.

Rumor busting: Goliath birdeaters do not primarily eat birds — they eat insects, frogs, and rodents. The name comes from a historical engraving depicting one eating a hummingbird. Also, the Goliath birdeater is not poisonous; it is venomous. And the ‘largest spider’ title is not a single record — there are two distinct records: weight and leg span.

Why Does the Distinction Between Weight and Leg Span Matter?

Which spider is considered “biggest” depends entirely on definition: mass or leg span. This is not a trivial distinction. The Goliath birdeater and giant huntsman spider evolved in different regions and habitats — the rainforest floor of South America versus cave entrances in Laos — and their body plans reflect those environments.

Size in spiders is often limited by oxygen availability and the structural limits of the exoskeleton. Modern spiders cannot reach the sizes of prehistoric giants like Megarachne partly because of these constraints. Understanding the distinction between weight and leg span helps clarify why no single spider holds all records and why the question “which is biggest?” has more than one answer.

The public’s fascination with record-sized specimens — reflected in 2025 searches for “biggest spider found dead” — points to a broader interest in natural history extremes. But without a clear definition, comparisons can be misleading. The most accurate answer is that the Goliath birdeater is the heaviest, and the giant huntsman spider has the longest legs.

Where Do Reliable Facts About the Biggest Spiders Come From?

Authoritative information on the world’s largest spiders comes from museum collections, scientific databases, and peer-reviewed research. The following sources were used to compile this article and are considered reliable by the scientific community.

The Wikipedia entry for the Goliath Birdeater provides a comprehensive overview of taxonomy, size, distribution, and behavior, with references to primary scientific literature. The Natural History Museum in London publishes an authoritative comparison at World’s Most Extreme Spiders, covering the heaviest species and sexual dimorphism. Discover Wildlife (BBC Wildlife Magazine) offers a ranking and size comparison at 10 Biggest Spiders in the World. The World Spider Catalog is the definitive scientific database for spider taxonomy. Taxonomic details for the Goliath birdeater are also available via the Integrated Taxonomic Information System.

For further reading, see the Comprehensive Research: Largest Spiders in the World and the Largest Spiders in the World — Detailed Comparison.

What Is the Final Verdict on the Biggest Spider in the World?

There is no single answer. The Goliath birdeater is the heaviest spider, weighing up to 175g, while the giant huntsman spider holds the record for the longest leg span at 30 cm. Both are remarkable animals that have adapted to very different environments. Neither poses a real danger to humans. For the most complete picture, the only honest answer is: it depends on how you measure.

Frequently Asked Questions