Spiders are the stuff of nightmares. Those terrifying monsters don’t need size to be scary. The sheer size of their multi-legged body is often enough to spook most people. But even in the scary critter world, tarantulas are king. The notorious reputation of this species of spider is partly due to its potent venom. But another reason they’re so scary is that they can grow big.
Some of the biggest spiders in the world are tarantulas, and the biggest of them all in terms of overall body weight is the Goliath birdeater (Theraphosa blondi). As adults, this massive spider is as big as a human hand and weighs up to six ounces. Here are some important facts about this giant arachnid.
Biggest Tarantula—Size and Physical Description
Generally, the title for the biggest spider in the world can be assigned either based on body weight or overall length. If the latter were our criterion for judging, then the title for the largest spider in the world would go to the giant huntsman spider (Heteropoda maxima). However, since this article is about tarantulas, the Goliath birdeater retains the top spot (because the giant huntsman spider is not a tarantula).
The Goliath birdeater is not just the world’s biggest tarantula. Thanks to its massive weight, it is also the biggest spider in the world. This spider weighs about six ounces (0.375 pounds) and has a body length of about five inches. The leg span of this spider is about 12 inches.
The Goliath birdeater is typically black or russet brown. A distinct feature of this spider is the presence of spines on its third and fourth pair of appendages. Goliath birdeaters also have four appendages near their mouth. Two of these appendages are used as fangs to deliver venom. These fangs are known as chelicerae. The remaining two mouth appendages are called pedipalps and are used as claws while feeding and as a sort of feeler. Male Goliath birdeater also uses the pedipalps during reproduction.
Where Does the Biggest Tarantula in the World Live?
The Goliath bird-eating tarantula is found naturally in the rainforests of northern South America in countries like Venezuela, Suriname, Guyana, Northern Brazil, and French Guiana. In these countries, it is mostly found in deep rainforest habitats, especially in swamps and marshy areas.
Most spiders tend to make their home in beautifully woven silk webs. However, the Goliath birdeater prefers to live in burrows. The spider lives in deep burrows that may already exist in well-covered areas under logs or rocks. It may also dig its own burrows and cover the entrance with webbing.
Goliath Birdeater Diet and Predators
The Goliath birdeater has a fitting, common name that clearly reflects the massive size of this spider. Ironically, this gigantic arachnid does not feed exclusively on birds, as the name suggests. The name is a reference to an 18th-century carving depicting a tarantula family feeding on a hummingbird.
Insects make up the bulk of the Goliath birdeater’s diet. However, it occasionally feeds on small birds, frogs, and rodents. They can eat pretty much any animal that is smaller than themselves. Tarantulas are nocturnal and the Goliath bird eater spends most of its days hidden in burrows. Usually, it will only crawl out at night to catch its prey.
When a Goliath birdeater catches prey, it digs its inch-long fangs into the animal’s body like a hypodermic needle, pumping neurotoxins into it. Although the tarantula’s venom is hardly ever fatal to humans, it can kill small prey quite effectively. The spider drags the dying animal into its burrows. Spiders cannot eat flesh. The venom helps to liquefy the prey’s inside then the spider sucks it out as food.
Given their large size and potent venom, Goliath birdeaters don’t have a lot of natural enemies. However, a few predators, such as the coati, can prey on them. This spider has bad eyesight, making it difficult to escape predators. They do have sensitive hairs on their body that are sensitive to vibration. This helps them to escape danger. The Goliath birdeater can make a “hissing” noise if threatened—a behavior unique to them alone but not seen in other tarantulas.
Another impressive defensive mechanism they have is their urticating hairs. These harpoon-shaped hair follicles have stinging bards, which they can use to ward off predators. When threatened, the spider can rub its legs together to launch the tiny hairs into the skin and eyes of the predator. These defensive mechanisms are often enough to protect the spider from predators attempting to attack it.
Reproduction, Development and Lifespan
Female Goliath birdeaters lay between 50 and 200 eggs at once. Their giant egg sacs are often covered in urticating hairs to protect the eggs and hatchlings from predators. The hatchlings emerge about three weeks later.
At maturity, males develop a finger-like appendage on their front legs. They use this to attach to the female fangs during mating. Males have a lifespan of three to six years and die off within a few weeks or months after mating. Females tend to live longer. They can survive for up to 20 years and will produce numerous hatchlings in their lifetime.
Mating typically takes place shortly after molting. The female carries the sperm from the males until she’s ready to lay her eggs. The sperm fertilizes the eggs as she passes them out of her body onto a mat of web rhat she has made.
Female Goliath birdeaters carry their eggs with them. The eggs are wrapped into a single ball about the size of a tennis ball. Each ball may contain as many as 70 spiderlings. The hatchlings continue to molt and develop in the giant ball. They develop rapidly, molting at least five or six times within the first year.
Can You Keep the Biggest Tarantula as a Pet?
Considering the massive size of this spider, the Goliath birdeater is obviously a handful. They are fast and defensive, making them difficult for beginners to handle. If you’re just starting out with raising pet tarantulas, this species is not recommended for you.
They have a ferocious diet and can grow big within a very short time. This giant spider can be kept in plastic or glass enclosures about 20-gallon long. You may use a bigger enclosure, but this isn’t always necessary.
Theraphosa blondi thrives better in a humid enclosure. You should lay a substrate containing a mix of vermiculite and peat or sand on the enclosure’s floor. The right substrate helps to keep the humidity at an ideal 80 to 85 percent. You will also need to place a bowl of water in the enclosure and mist regularly. While the enclosure needs to be humid, proper ventilation is necessary. The ideal temperature for this type of spider is about 75 degrees Fahrenheit to 82 degrees Fahrenheit.
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- National Zoo, Available here: https://nationalzoo.si.edu/animals/goliath-bird-eating-tarantula
- Top Flight Dubia, Available here: https://www.topflightdubia.com/goliath-birdeater-tarantula-care