The goliath birdeater tarantula is a fascinating creature, and one of mammoth size for its kind. But are they harmless? Their sounds and intimidating characteristics may be misleading. Find out why.
The goliath birdeater (Theraphosa blondi) is one of almost 900 species of tarantulas. This giant huntsman spider is considered the largest by leg span (12 inches). It was named goliath because of its massive size and birdeater because it was seen eating a hummingbird when discovered by explorers in the 1800s. They can be found living in swampy areas in South America's rainforests. Their homes are deep in the ground in burrows that have been abandoned by small animals. Although scary looking, these amazing spiders are quite harmless. (Click on image to enlarge.)
Goliath birdeaters weigh about 6 ounces. Their leg span is fairly close in size to that of the giant huntsman spider, about 10 inches. The largest on record is just over 11 inches. The body is dark brown and covered with reddish hairs. They have eight legs and two appendages (pedipalps) in the front that act as arms to help push food into their mouth.
All tarantulas molt (shed their exoskeleton) to grow. When going through this process, they will lie on their back, will appear to be dead and are completely vulnerable. The process can take anywhere from 15 minutes to several hours. If missing a leg, it will regenerate a new one, but it will normally be smaller and not as functional as the original.
Sight and Sound
Goliath birdeaters are practically blind, despite their eight tiny eyes. Distinguishing light from dark is about the best they can see. To get around, they rely on ground vibrations. They can make a loud hissing sound by rubbing the bristles on their two front legs and appendages together. This is called stridulation, and can be heard up to 15 feet away.
Behavior and Defense Mechanisms
These spiders are nocturnal, meaning they are active at night. They are solitary creatures and will only spend time with another spider of its kind when mating. They are basically harmless to humans, and will not attack a person unless they feel threatened. They are venomous. If the spider does bite a human, the effects are similar to a wasp's sting. A bite will not always contain venom - this is known as a "dry bite". Another defense mechanism they possess is the ability to flick urticating hairs from their abdomen using their hind legs at anyone they perceive as a threat. These hairs can be very irritating, especially if they come in contact with the eyes, nose and mouth, and are known to kill small mammals like mice.
Goliath birdeaters will eat young birds from their nests, but their diet normally consists of insects. They are also known to eat bats, small snakes, lizards and frogs. To capture their victim, they will sneak up on it, pounce on it and inject their venom. These tarantulas do not have teeth, so they regurgitate digestive juices onto their prey, which breaks down the soft tissues for them to slurp up.
Mating takes place in spring and early summer. The female lays about 100 to 150 eggs in a sac protected with a layer of silk that she will carry with her when she leaves the burrow. The incubation period lasts about two to three months. The baby spiders will stay with their mother for a few weeks before finding their own burrow. It takes about three years for the young spiders to mature.
The following are more fun and interesting facts about this goliath spider:
Unlike other spiders, tarantulas have a jaw that moves up and down, instead of side to side.
- The male has to be very careful when mating with a female because when he approaches her, she may mistake him as prey and will attack him.
- The lifespan of a male is 3-6 years, and the lifespan of a female is up to 20 years.
- The goliath birdeater tarantuala is a good source of protein. They are said to be quite tasty by people in South America who eat them.
The Big Zoo: http://www.thebigzoo.com/Animals/Goliath_Bird_Eating_Spider.asp
Natural History Museum: http://www.nhm.ac.uk/nature-online/species-of-the-day/biodiversity/loss-of-habitat/theraphosa-blondi/behaviour-biology/index.html
Extreme Science: http://www.extremescience.com/zoom/index.php/creepy-crawlies/11-biggest-spider
Tarantula Guide: http://www.tarantulaguide.com/tarantula-molting/
Photo by Big Bug Show / Flickr