Tarantula

“ Where do tarantulas live?
They can be found in the south- and west parts of the USA, Central America and down throughout South America to the southern parts of Chile, Argentina. Tarantulas can also be found throughout Africa, large parts of Asia and all over Australia. In Europe, there are some species in Spain, Portugal, Italy, Turkey and in Cyprus. Around 840 described species have been found over the world. They live in warm climates - in dry hot semi-deserts or in humid rainforests. Most are terrestrial and live in burrows, but some are arboreal, e.g. Avicularia. 

Briefly about anatomy...
Tarantulas have eight legs like every kind of arachnid plus a pair of pedipalps. In the scorpion family these are developed to claws but spiders are lacking the claws on the pedipalps. These are used for grabbing the food items, to touch and in mating. The rear end of the spider is called abdomen and the front part cephalothorax, and the top of the cephalothorax is called carapace. The eyes are located on the top of the carapace (Some Spelopelma species are the only theraphosids that lack eyes, they live in caves) and underneath are the mouth and the chelicera with its fangs. The respiratory organs are located in the abdomen, they are called booklungs, and the stomach. 

"Deadly tarantula found in the kitchen"
Nothing could be farther from the truth! Ok, tarantulas are venomous but not dangerous to humans in general. There are, however, some exceptions. Poecilotheriaand Stromatopelma can be dangerous even for us, humans. Coma after a bite from a Poecilotheria has occurred but, so far, there has been no report of human fatalities having resulted from a tarantula bite. 

The species from the Old World seem to have more potent venom than New-World species. The mechanical damage after a bite can be quite large–the fangs are often larger than those of most venomous snakes! If you get allergic reactions from a wasp sting you should be extra careful. The tarantula family does not include the infamous funnel web spiders. They are Hexathelids, australian funnel web spiders, despite what some popular books are saying. The funnel webs are however mygalomorphs. 

At the end of the abdomen are the anus and the spinnerets. Tarantulas are often very hairy and the American species use special urticating hairs on their abdomen as a defensive weapon. These are located on the abdomen and can be kicked off using the back legs, against an aggressor and it results in pain and irritation. Some of the hairs can be used for locating food, picking up particles in the air to sense the temperature and humidity. The species from the Old World do not have the urticating hairs, they are using their powerful chelicera for defense instead. I have called it hair but it isn’t really hair like the mammal hairs growing out of a hairsack. It is more like spines made of chitin, the same material the entire exoskeleton of the tarantula is made of. The proper word would be setae instead of hair. 

The size of a tarantula is everything from a centimeter to the gigantic Theraphosa blondi that reaches legspan of 25 cm, body length of around 9-10 cm and a weight of 150 g. 

The largest spider in the world?
Which species are the biggest? It is for sure one of the theraposids but which one? Theraphosa blondi are probably the biggest but Xenesthis, Lasiodora, Pamphobeteus,Pseudotheraphosa are strong contenders to the title. In 1925, a female T. blondi was found that measured 25.5 cm in legspan and, in 1945, a female Lasiodora klugi that measured 24 cm in legspan was found. In 1982, a female Pamphobeteus antinous was found and she measured 24.1cm in legspan. I have heard of larger specimens held in captivity, and that are very likely due to the fact that captive spiders get lots of food from being spiderlings to adulthood and can grow to the maximum. I haven’t seen any spider over 30 cm in legspan but perhaps they can grow that large. Hmm, my blondi is right now about to molt... 

The spider enemy
Smaller animals like insects, frogs and mice might consider the spider as their number-one enemy but do the spiders have enemies of their own? Yes, smaller predators that are searching the rainforest floor for food such as the coatimundi will gladly dine on a fat tarantula for lunch, but not without difficulties–would they encounter a large Theraphosa blondi, a female that is willing to spray the coati’s nose full of urticating hairs, the coati is in trouble. The most notorious of the spider antagonists is probably the tarantula hawk, a large wasp. The largest are around 10 cm in length. They capture the spider by injecting it with venom that does not kill the spider but paralyzes it. The wasp can bring it home to its burrow and lay an egg inside the body of the spider. The newly hatched wasp eats the spider alive from the inside while it is still alive... 

Another enemy is the scolopender, an arthropod that is searching constantly for food on the forest floor. The largest species, Scolopendra gigantea, gets around 40 cm in length. Then of course, perhaps the biggest threat to the well being of spiders are people. Deforestation is one of the reasons that several species of animals face extinction, not only spiders. ”