Goliath Birdeater: the largest spider in the world, or not?

Spiders come in all shapes and sizes, from small, intelligent jumping spiders to the extremely deadly and funny Hercules. Giant mythical spiders have been depicted time and time again throughout history – most recently in the form of Adam Sandler’s space therapist – but fiction aside, what’s the biggest spider currently stomping around the Earth with us?

Narrowing it down to the definitive beast of all eight-legged beasts is a difficult task, as many spiders have similar sizes and many species exhibit sexual dimorphism. Sexual dimorphism describes the physical differences between males and females of the same species. In some spider species, such as many reptiles, females are larger than males, allowing them to carry a greater number of eggs.

In general, spiders can be divided into two groups or “suborders”. Araneomorphae make up 90 percent of the spiders on Earth and are considered “true spiders.” These include species of orb weavers, jumping spiders and huntsman spiders, all of which are characterized by fangs that are angled together in a pincer-like manner.

The second group consists of ancient spiders called mygalomorphs. This group, consisting of more than 3,000 species, includes all tarantulas, trapdoor spiders and funnel-web spiders. Distinguished in part by their downward canine teeth, they are considered more primitive than the araneomorphs, having remained relatively unchanged for thousands of years. Due to their slow evolution, they have retained certain features of antiquity, namely their impressive size.

The Goliath bird eater

Black Goliath bird-eating spider sitting on man's hand.  Isolated Halloween concept.

A relatively small example of a Goliath bird eater.

Image credits: PetlinDmitry / Shutterstock.com

Measured in terms of size and mass, the largest spider in the world is the Goliath bird eater (Theraphosa blondi), more specifically the female Goliath bird-eater, which is described as being the size of a young puppy.

It is speculated that the name comes from a 19th century engraving depicting a tarantula eating a hummingbird. Theraposa gender is labeled as ‘bird eaters’. However, others believe that the name comes from an account of South American explorers in the 16th century who came across some chicks that had fallen into the web lining of a Goliath burrow, leading to the assumption that these small birds were the intended prey of the were spider.

However, the name “bird eater” is a bit of a misnomer, as Goliath bird eaters, like many giant spiders, feed primarily on worms, amphibians and large insects. But thanks to their large 2.5 centimeter (1 inch) fangs and powerful neurotoxin venom, they are more than capable of eating small birds and other similarly sized prey, such as small rodents.

But despite being fatal to many smaller species, Goliath bird-eater venom is not fatal to humans. However, humans are harmful to Goliath bird eaters as they are said to be a delicious delicacy when roasted in banana leaves.

Like many spiders, Goliath bird eaters are nocturnal and almost completely blind. Instead, they rely on their sensitive, furry bodies to detect light vibrations and guide them to their next meal. They also have impressively long lifespans: female Goliath bird-eaters live for about twenty years, while their relatively small male counterparts generally live only three to six years.

While many tarantula species make great pets and have docile temperaments, the Goliath bird eater is one of the more brazen species. They are known for being skittish, nervous and even aggressive, with their impressive teeth potentially causing a nasty bite.

The Giant Hunter

Giant huntsman spider on rough surface

The giant huntsman spider lives mainly in caves.

Image credits: Nikhil Guhagarkar / Shutterstock.com

However, it can be argued that the Goliath bird eater is not the largest spider in terms of leg span. Despite this being the main reason why arachnophobes tend not to visit Australia, the giant huntsman spider (Heteropoda maxima) is mainly found in Asia, where it was only first identified in 2001 in a cave in Laos.

There are thousands of subspecies in the huntsman family (Sparassidae), many of which are common in Australia, Asia, Africa and South America, but only a few people have actually seen a wild giant hunter in the 23 years since its discovery.

The hunter family gets their name from the way they catch their prey. No, this doesn’t mean it “hunts humans”, just that it is a hunting species that does not catch food using a web. Instead, they will spend much of their time hiding and waiting to ambush their next meal.

How big is the largest spider in the world?

In terms of size and mass, the Goliath bird eater wins hands down for ‘largest spider’. With a leg span of 28 centimeters (11 inches) (the size of a dinner plate), a sturdy body that stretches 13 centimeters (5 inches) and a hefty weight of 175 grams (6 ounces), these spiders have been able to to amass an impressive mass by being an adult, burrowing species.

But if you like lanky spiders, the giant huntsman wins because it has the longest legs. Unlike many other spider species, it is the male giant hunter that has the largest leg span, although the females have larger bodies.

If you thought Goliath’s legs were impressive (or terrifying), this lanky freak has a leg span of about 30 centimeters (12 inches), the size of, well, a very large dinner plate. However, the giant hunter is much slimmer than the Goliath bird-eater, with a body length of only 5 centimeters (2 inches) and a pitiful weight of only 167 grams (6 ounces), which is decidedly puny when compared to the mighty Goliath.

Where is the largest spider in the world?

It’s behind you! Just kidding, unless you live in the dense rainforests of northern South America, where the Goliath bird-eater creates its terrestrial, web-lined burrows in the soft ground. Found in Venezuela, Northern Brazil, Guyana, French Guiana and Suriname, these fatties tend to keep their pig-like bodies close to the ground and hide under rocks and roots. The round body build of tarantula species makes them particularly susceptible to fatal injuries caused by falls from relatively low heights, so most like to have many feet on solid ground.

The most athletic of our pair, however, are native to Laos, where the freakishly fast giant hunter lives in caves and other dark spaces. They prey on insects, small reptiles and even rodents, but although they are mildly poisonous, their venom is not potent enough to seriously harm humans. However, they are masters of the jump scare and can run at mind-boggling speeds of almost 1 meter per second.

Even more impressive arachnids

Adult female Brazilian salmon pink tarantula, King Baboon Tarantula, Grammostola anthracina spider walking on the ground, face sized tarantula on a rock.

Top left: Brazilian salmon pink tarantula. Above right: King baboon tarantula. Bottom left: Brazilian giant tawny red tarantula. Bottom right: Face-sized tarantula.

Image credits: George Chernilevsky / Shutterstock.com, Audrey Snider-Bell / Shutterstock.com, Russell Marshall / Shutterstock.com, Ranil Nanayakkara / British Tarantula Society / Wikimedia Commons (CC BY 3.0 DEED)

The closest relatives of the Goliath bird eater are also among some of the largest arachnid species. The pink-footed goliath (Theraposa apophysis) and the Brazilian salmon-pink birdeater (Lasiodora parahybana) both have a similar leg span of about 11 inches, but neither can match Goliath’s large body and impressive weight.

Furthermore, the Hercules baboon spider is of similar size (Hysterocrates Hercules) and king baboon spider (Pelinobius muticus), native to West and East Africa respectively, are the largest spider species on the continent, with a wingspan of up to 20 centimeters (8 in). They are so called because their legs resemble a baboon’s fingers.

Another South American giant, native to Paraguay, Argentina and Brazil, is the Brazilian giant tawny red tarantula (Grammostola anthricina). With a leg span of 25.5 centimeters (10 inches), this beast, while beautiful, has venom that is harmful to humans. However, it has a famously calm and docile temperament, making hostile encounters with humans unlikely.

And finally, a recent discovery in 2009 rewarded the innocent Poecilotheria rajaei the terrifying name “face-sized tarantula”. Although harmless to humans, due to deforestation in its native habitat, Sri Lanka and India, the face-sized tarantula can often be found in buildings. If you happen to find one on your face, the 20-centimeter (8-inch) leg span would indeed cover most of it.

Deforestation is a major problem for all large spider species, despite many not yet officially classified as endangered. Many species are slowly being displaced from their natural homes, increasing the likelihood of interaction with humans, where they are further threatened by the widespread demonization of these beautiful beasts.

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