That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

In Part I of this article I talked a bit about collecting (or trying to collect!) the Huntsman Spider, Heteropoda venatoria, in a most unlikely setting.  Usually purchased as a “curiosity”, the Huntsman often surprises its new owners with a range of interesting behaviors – if you thought that spider pets were limited to tarantulas, please consider this fascinating alternative!

Caution: Although Huntsman Spiders are not considered to be dangerously venomous, they are fast and aggressive, and will not hesitate to bite.  We know little about spider venom, and the possibility of an allergic reaction must be considered (central nervous system reactions have been reported on rare occasions)….please do not touch any spider with bare hands.

Natural History

The Huntsman Spider likely originated in southern India and Sri Lanka, but is now well-established in warm regions worldwide (including Florida).  They frequently enter buildings, where they sometimes welcomed for their roach-catching abilities.

The alternate name, Giant Crab Spider, took hold because these spiders hold the first 2 pairs of legs spread-out like a crab on guard.   Huntsman Spiders build no webs, but rather run down their prey, and are quite ravenous.  I’ve observed youngsters being dragged about by roaches three times their size, and adults sometimes catch lizards and small bats.

Huntsman Spiders are entirely arboreal and adapted to living upon flat surfaces, such as walls and tree trunks, as opposed to branches.

Huntsman Terrariums

In captivity, they take readily to cork bark  and will climb terrarium glass as well.  Position cork bark slabs near the glass, so that the spiders will remain visible when using the reverse side of the bark as a shelter.

While arboreal tarantulas (i.e. Pink-toed Tarantulas, Avicularia spp.) do well in standard aquariums turned on end to provide additional height, I hesitate to recommend such for Huntsman Spiders – opening the screen cover leaves a wide area available for escape.  I much prefer a “tall or high style” aquarium, with the cover is on top.  Alternatively, a Faunarium turned on its end might work, as the access door is small and should limit escapes.

Heat and Humidity

Huntsman Spiders favor warm, humid habitats, and should be maintained at 77-85 F and provided daily misting and a moisture-retaining substrate.

Diet

Huntsmans take nearly any insect prey available, but particularly favor roaches.  Wild caught moths, katydids, beetles and grasshoppers should also be provided whenever possible.

Breeding

Male Huntsman Spiders are smaller and thinner than females, and their carapace bears darker markings.  When ready to breed, males cease feeding and develop noticeably swollen pedipalps (leg-like structures bearing sperm packets).  They wander about in search of females to mate with (and, usually, to be consumed by!). I’ve had breeding males escape with their lives, but none have survived for long afterwards.

The female carries her uniquely flattened egg case below her body.  The young stay on her for a short time, and then disperse.  If you are raising this species, be sure to cover the terrarium’s screening with an extra layer of mosquito netting, lest the hatchlings escape – a colony established in the home is not to everyone’s liking!

Further Reading

Huntsman and other spiders produce a range of sounds.  An interesting article on this topic, which includes photos of males in breeding condition, is posted here.

A video showing this species’ speed and hunting style is posted

Huntsman Spider image referenced from wikipedia and originally posted by Ed g2s and Saperaud

As a boy, my favorite exotic animal collecting site was, of all places, the loading dock of the local A&P Supermarket.  Raymond Ditmars and other famous city-born naturalists had taken this route, and so I followed.  The store was not far from the Bronx’s Hunts Point Market, where trucks from all over delivered fresh produce. Hidden within the produce crates were the creatures I sought – tree frogs, spiders, lizards, insects and such (I once narrowly missed a Mouse Opossum).  All large spiders were called “Banana Spiders”…one, the Giant Crab or Huntsman Spider (Heteropoda venatoria), appeared on occasion but was always too fast for me.  I became obsessed with this beast, whose leg span approached 6 inches, but, try as I might, I remained crab spider-less.

Meeting Both a Long-Lost Spider and Entomologist

It was to be over 15 years before I next crossed paths with the Huntsman Spider – this time in a Bronx Zoo building (JungleWorld) in which I worked as an animal keeper.  A huge population, having arrived with tropical plants, was established, and I was ecstatic (my mammal-keeping co-workers were far less impressed!).

The spiders were faster than I remembered (and I was slower!)…those I captured had mainly fallen into places from which they could not escape.  They proved surprisingly easy to breed and, once set up in our exhibit area, were very popular with our visitors.

I took a specimen to the American Museum of Natural History, where it was identified as Heteropoda venatoria.  Amazingly, the woman who identified the spider for me was famed invertebrate specialist Alice Gray…while speaking, we discovered that it was she who had answered my mantis rearing questions when I called the museum as a boy, 25 years earlier!

Captive Care

These impressive spiders occasionally appear on the price lists of Florida-based reptile dealers, and they are quite inexpensive.  If a few guidelines are followed, they make fascinating, active terrarium inhabitants, and breed readily.  Once their amazing speed in hunting is seen in action, even die-hard tarantula fans cannot resist them!

I’ll cover the natural history and captive care of Huntsman Spiders in Part II of this article.

Further Reading

An interesting article on this spider’s life cycle is posted at on the website of the Cambridge Entomological Society.

Male Huntsman Spider image referenced from wikipedia and originally posted by B. Navez

A great many people are fearful of snakes and spiders, often to a seemingly unreasonable degree, and without any prior negative experiences.  Researchers have long sought to discover if people possess an inborn, instinctual aversion to these creatures, or if learning is involved.

Living Near Venomous Animals

My own view has always been that it makes sense for people living in the tropics to avoid all snakes and spiders, and I’ve observed that this lesson is taught to children early in life in many places.

There are still over 10,0000 snakebite deaths yearly worldwide, and in areas of high species diversity it is nearly impossible to distinguish all venomous from harmless species (in recent times, 2 renowned herpetologists were killed by snakes not know to be venomous).  On my first research project in Costa Rica, I foolishly believed that I would be able to identify many of the snakes and spiders I might encounter.  My first nighttime walk through overgrown scrub quickly taught me otherwise!

Another important point to bear in mind is that animals, especially snakes and spiders, are drawn to homes and gardens due to an unnaturally high density of prey (rodents, insects) and in search of shelter.  During the dry season in Venezuela, I collected numerous treefrogs, bats and spiders indoors.

Snakes and Primate Evolution

So, based on my experiences, I leaned toward a learning-based explanation.  However, recent work at UC Davis has revealed a possible evolutionary explanation to snake aversion among monkeys and, it is theorized, humans.

Fossil and DNA evidence indicates that large snakes may have been among the first serious predators of modern mammals, and were possibly the driving force behind the development of keen eyesight in Primates. The evolution of the Primate vision system seems linked very closely to fear and vigilance receptors in the brain.  As Primates became better at spotting snakes, snakes developed more effective camouflage, and so on.

On Madagascar, where large snakes are absent, Primates (lemurs) have not developed the excellent vision possessed by their relatives on mainland Africa.

 Most primates do indeed react with “instinctive” fear upon seeing a snake for the first time.  However, I have noticed that a great many creatures, ranging from rodents to elephants, treat novel objects with caution, however harmless they might be.

Research Involving People

Experiments involving people have yielded mixed results.  Studies conducted at the Universities of Virginia and Queensland has shown that snakes and spiders draw far more attention from human observers than do other potentially deadly animals or objects.

But many of us have (or, at least, I have!) seen toddlers squeal with delight when presented with a spider or snake…yet they will become quite scared if they see an adult express fear.

One thing I’ve noticed is that snakes and spiders have “odd shapes” (except to herpers!)…I wonder if this draws attention; and anything that moves suddenly can startle an observer, especially if it is new to that person.

Teach Them Early

It seems we must wait awhile for answers that may help people overcome their fears and view our cold-blooded friends more reasonably.  Until then, please do your part to introduce the next generation to nature early…the little guy pictured here will have no excuses for disliking herps – I’m starting him out on amphibians, and working my way up the “fear scale”!

Further Reading

You can read more about some of the research mentioned here.

In Part I of this article, we learned that less than 1% of the world’s 40,000+ spider species are dangerously venomous.  Today I’d like to highlight their valuable role as insect predators and point out a few reasonable precautions that should be taken when keeping spiders in captivity.

Hunting Methods and Diet

Spiders consume animals ranging from mites to birds.   Not all ensnare their prey in webs…some hunt by running (wolf spiders), swimming (European diving bell spider), spitting silk (spitting spider), hiding in flowers (crab spider), throwing webs (bolas spider), luring fishes while floating (fishing spiders) or rushing from burrows fitted with hinged doors (trap door spider).

However, all spiders consume insects, including agricultural pests and disease-bearing species, to some degree.  Field research has shown that harmful flies comprising over 60% of the diet of certain web-building species.  It is estimated that the weight of the insects consumed yearly by spiders in New Zealand exceeds that of the island’s human population!

Precautions – Bites and Urticating Hairs

The fact that so few spiders are dangerous to people should not be taken as a license to ignore caution when dealing with them. Just as with bees and other venomous animals, allergic persons can be injured or killed by the bites of relatively benign species, and potentially fatal infections can be associated with the bite of any animal.

Also, many tarantulas shed urticating (irritating) hairs when disturbed or even when just moving about. A colleague of mine underwent major surgery to remove such hairs, deposited on his hand by a “tame” red-kneed tarantula, from his eye.

That being said, I have kept native and exotic spiders since childhood, and have never been bitten – because I do not pick up spiders with my hands.  I urge you to handle spiders, if at all, with plastic tongs or by ushering them into a container.

Further Reading

The diving bell spider is certainly one of the world’s most interesting invertebrates – living within a submerged shelter that exchanges oxygen with the surrounding water and swimming after small fishes!  To read more, click here.

Misumena vatia with wasp image referenced from wikipedia and originally posted by Olei.

Scorpion venom has recently undergone an image upgrade…once feared, these little-studied toxins are now yielding valuable medicines. Researchers at China’s Wuhan University have recently (August, 2009) discovered 9 new types of peptides and proteins in the venom of Scorpiops jendeki, a scorpion native to southwestern China.

Current Research

Although considered only mildly toxic, S. jendeki’s venom is quite complex, containing at least 19 different proteins. Scientists believe that these molecules may be useful in synthesizing new drugs. Newly discovered molecules, which may attack cells in novel ways, are always looked upon with great interest by medical researchers working with incurable diseases and drug-resistant microbes.

Role for a Deadly Scorpion

In recent years, even the much-maligned “death stalker” or Israeli yellow scorpion (Leiurus quinquestriatus) is being treated with new respect in the lab – an irradiated version of a protein in its venom shows great promise in the treatment of brain cancer.

Further Reading

You can read more about current research involving scorpion venom and brain cancer at http://www.nano.org.uk/news/april2009/latest1847.htm.