The Goliath Birdeater (Theraphosa blondi) is one of the largest spiders in the world, found in the rainforests of northern South America. Its impressive size often raises questions about its potential danger to humans, particularly regarding whether it is “poisonous.” While it does possess a defense mechanism involving toxins, understanding their nature clarifies the actual risk.
Clarifying the Terms: Poisonous and Venomous
The terms “poisonous” and “venomous” describe different ways an organism delivers toxins. An animal is poisonous if its toxins are harmful when ingested or absorbed through touch. Examples include certain plants or dart frogs.
Conversely, an animal is venomous if it actively injects toxins into another organism, typically through a bite or a sting. Spiders, including the Goliath Birdeater, and snakes are venomous creatures, as they use specialized structures like fangs to deliver their toxic compounds.
The Goliath Birdeater’s Venom and Its Effects
Like most tarantulas, the Goliath Birdeater carries venom, which it can inject through its fangs. These fangs are substantial, capable of reaching lengths of 2 to 4 centimeters (0.79 to 1.57 inches), and can certainly break human skin. Despite their intimidating size, the venom is generally mild and not medically significant to healthy humans.
A bite is often compared to a bee or wasp sting, causing localized pain, swelling, and redness. While systemic effects such as nausea or muscle cramps are rare, they can occur in sensitive individuals. The spider usually bites only in self-defense, and not all defensive bites result in venom injection, sometimes being a “dry bite.”
Beyond the Bite: Urticating Hairs
Beyond its venomous bite, the Goliath Birdeater possesses another primary defense mechanism: urticating hairs. These fine, barbed bristles are located on its abdomen and can be flicked off by the spider when it feels threatened. These hairs are a more common concern for humans than the spider’s bite.
Contact with these hairs can cause significant irritation. On the skin, they may lead to itching, rashes, and hives, often described as feeling like sharp shards of fiberglass. If inhaled, the hairs can cause respiratory irritation, and contact with the eyes can result in severe irritation and potential corneal damage. Reactions to these hairs can also become more pronounced with repeated exposure.
What to Do if Exposed
Should a person be bitten by a Goliath Birdeater, clean the wound thoroughly with soap and water. Apply a cold compress to the affected area to manage localized pain and swelling. If symptoms worsen, or if signs of infection like increased redness, pus, or fever develop, seek medical attention.
In cases of contact with urticating hairs, wash the affected skin immediately and thoroughly with soap and water. Avoid rubbing the eyes to prevent further irritation. For any eye irritation or respiratory issues from hair exposure, professional medical evaluation should be sought. Taking precautions such as wearing protective gloves, long sleeves, eye protection, and a mask can help prevent exposure to these irritating hairs.