The Much (unfairly) Maligned Tarantula

The Much (unfairly) Maligned Tarantula

 

By Susana Cortázar

The name alone – tarantula – invokes fear, shudders, visions of old, black and white Saturday afternoon B-movies where explorers and archaeologists died horribly painful deaths in the middle of the jungle because they were miles from the nearest tarantula anti-venom station.  Never mind that there is no anti-venom for tarantula bites or that there has never been a documented human death from a tarantula bite. Seriously.  Yet, this arachnid instills fear in even the bravest of men (and women). 

Also contrary to popular belief, they are not the largest arachnid around.  That honor goes to a scorpion from India.  The largest tarantula in the world is the Goliath bird-eater, which can reach a leg span of 12” and a weight of 5 ounces. The smallest was discovered 10 years ago and is the size of a mere fingernail.  Tarantulas are found all over the world in tropical, sub-tropical and desert climates. 
 
Mexican red-knee tarantula                                                                
Photo by Nicole Atteberry

I met with Zoo Miami Curator of Ectotherms Nicole Atteberry, who is a fountain of information.  When I asked her why tarantulas have such a bad reputation and inspire such terror, she said that, while, “for the most part, yes, they are harmless, they may make you hurt yourself if you encounter one by surprise or just have a phobia!  I think spiders, in general, get a bad rap by humans because they are so un-like us that it is hard for people to relate to them.  It is easy to look at a cute, furry puppy and equate a human quality to it based on its mannerisms.  It is a little more difficult to look at a ‘cute’ furry spider that walks on eight legs, has eight eyes, can run up a wall, and empathize with that creature.  Hopefully, the popularity of Spiderman will at least give them some good PR.” Yes, Nicole is also quite funny.

The reactions to tarantula bites on humans depend on many factors, such as the person and the species of tarantula – some of the Old World species have a more potent venom.  Small children or immune-compromised people are more likely to react more seriously.  And what are some of the symptoms you can expect from a tarantula’s bite?  According to Nicole, “from swelling and pain (like a bee sting), to muscle spasms and cramping, and an elevated heart rate.  And then there’s the emotional reaction.  Panic can be a powerful thing!  But there has never been a human death associated with a tarantula bite.”  See, I told you.  Remember my first paragraph?
 
Indian Ornamental tarantula               Photo by Nicole Atteberry

When I asked Nicole if tarantulas bite out of fear, stress, or for sport, she responded in her matter-of-fact manner, “I think the only creature that bites for sport is Mike Tyson. (Did I mention that Nicole is quite funny?)  A tarantula will bite out of fear.  Considering they are pretty much a blob of liquid goo inside a shell, biting is really  their only defense.  But the primary reason a tarantula uses its fangs is to grasp, hold, and inject the venom into its prey, which helps paralyze and begin to ‘liquefy’ it, making it easier to swallow and digest.” 

Tarantulas don’t have blood, but rather hemolymph, a clear to whitish liquid that transports oxygen throughout its body, much like blood works in humans and other animals.  They have four pairs of legs and two pairs of appendages, called pedipalps, which enable them to sense and capture prey. They are carnivorous and eat insects and other arthropods.  However, large tarantulas have been known to eat small rodents, lizards, birds, and even other tarantulas! 

Interestingly, the male uses the pedipalps in reproduction to transfer sperm into the female.  “The male constructs what is called a sperm web where he deposits his sperm. He then attracts a female to the spot by drumming his legs. The male lifts the front portion of the female and inserts the sperm into a furrow on the underside of the female,” explains Nicole.  After mating, it can take anywhere between four to 20 weeks to lay the egg sac and hatching happens between four to 16 weeks later. 

And why, oh why, are tarantulas so hairy?  Well, the hair helps them sense.  Since they do not build webs like other spiders, they cannot use them to capture prey.  So the urticating hair acts as a detector and can physically capture their prey. “The hairs are very, very sensitive to vibrations (so don’t knock on the glass when you visit the zoo…it’s not nice!!).  They follow vibrations through their hairs to orient to and capture their prey.  And yes, some of the New World species of tarantulas can actually throw their hairs off of their body as a means of defense (they usually throw them off their rump as they are running away).  This can be extremely irritating to a predator and to a person…you don’t want those things embedded in your eyeball,” continues Nicole.  It’s the same sensation you get if you play with the insulation in your home.

Tarantulas have an exoskeleton (external) muscular support, almost like a shell, which protects its internal organs.  They also molt because as they grow, they run out of room in their outer shell and need more space.  While young tarantulas can molt as frequently as once a month, adults do so once a year.
 
                     Gactaeon - Brazilian red-trumped tarantula            Photo by Nicole Atteberry

Tarantulas come in various colors and patterns, which is probably a result of their environment and evolution, and they use their markings as camouflage from predators, which include raccoons, skunks, possums, lizards, birds, and other tarantulas.  There are some parasitic wasps that lay their eggs on a tarantula, and when the eggs hatch, the larvae eat the tarantula alive.

A misconception most people have is that the black widow is a tarantula.  While an arachnid, it is not a tarantula.  Tarantulas belong to the family Theraphosidae  and black widows belong to the family Theridiidae.  “The venom of the black widow is highly neurotoxic to humans.  Not that they go about their days looking for humans to harm, it is just a series of ‘unfortunate’ evolutions that make humans reactive to their venom,” adds Nicole.

Although not Italian, their name originated in Taranto, Italy.  This is probably because there is a wolf spider in Italy that looks like, but is not, a true tarantula.

Although people claim to be afraid of tarantulas, many keep them as pets. With proper care, females can live 20 – 30 years, so before getting one, make sure you’re ready to make that long-term commitment.  They are fairly easy to take care of and don’t need a lot of space so you can have them even if you live in small quarters.  But always do your research – just like you would before acquiring any other pet.  While some tarantulas are very easy-going, others are aggressive and will bite.  Nicole suggests you purchase “captive born specimens” so that you are not supporting poaching.  However, if after buying one you decide it’s not the right pet for you, there are many resources available to dispose of it – local zoos, societies, hobbyists, and breeders.  But please, don’t ever release it into the wild.

When I asked Nicole for any other interesting tarantula fact or if she owns any, her reply was quite revealing – and of course, humorous.  “Well, for one, they can vary in personality.  Some are shy, some aggressive.  Also, there is research under way to determine if tarantula venom has any medicinal properties, including treatments for muscular dystrophy.  I don’t own any tarantulas now (although I kept them when I was a kid).  But I DO care for a large collection here at Zoo Miami that is housed in my office.  I have 38 spiders in there…and they come in handy if I’m trying to get someone to leave!”   Good move, Nicole!
 
Gooty sapphire ornamental tree spider                                              Photo by Nicole Atteberry