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

The largest true (“non-tarantula”) spiders that most folks in the USA will ever encounter, Fishing Spiders are at once fascinating and a bit intimidating. This is especially so for egg-guarding females, who may prefer to fight rather than flee when disturbed. I recently came across one such female below a dock, while accompanied by my 5 ½ year old nephew. Thanks to my long career as a zookeeper, the little guy has been up close to a huge array of animals since infancy, and especially favors spiders. After locating the spider, we swam out from beneath the dock to plan our capture strategy. Noting my sidekick’s smaller size, and the fact that he has handled snakes longer than himself, I suggested that he go back and collect it, as the area was cramped. “No way, man” was all he said!

 

But ferocious appearances aside, Fishing Spiders make great terrarium inhabitants. Due to their size and boldness, they are very easy to observe as they catch fish, walk on water and care for their eggs and young. I’ve never understood why more spider enthusiasts have not taken an interest in them… perhaps this article will change some minds!

 

Tarantulas are not the only Vertebrate-Eating Spiders

Most folks know that large tarantulas sometimes catch small lizards and other vertebrates, but among the true spiders this strategy is relatively unstudied. A recent survey of the subject, published in the June 18, 2014 issue of Plos One (please see link to article, below) revealed that at least 18 species in 8 families feed upon fish. Despite being small and slightly built by tarantula standards, Fishing Spiders, aided by vertebrate-specific neurotoxic venom, can take prey that exceeds their own weight 5-fold.

 

North America is particularly rich in Fishing Spiders, most of which are classified in the family Pisauridae. Eleven family members are documented fish-catchers, and others may do so as well. Also known as Nursery Web Spiders, some live far from water and eat insects, while others move between aquatic and terrestrial habitats.

 

The Dark Fishing Spider

My favorite is the Dark Fishing Spider, Dolomedes tenebrosus, which ranges from southern Canada west to North Dakota and south to Florida and Texas.Females measure over 1 inch in body-length, and their legs span 3+ inches. The grayish-brown body is marked with black, and the legs are banded, but individuals vary.

 

Maternal Care of Eggs and Young

Female Dark Fishing Spiders carry their egg cases, which may contain up to 1,400 eggs, suspended between the chelicerae (fangs), pedipalps, and spinnerets (large wolf spiders, which resemble fishing spiders, carry their eggs at the rear of the body, attached to the spinnerets).

 

Egg-guarding females that I collect in July often produce a second fertile egg case in September. Those I’ve kept near an east-facing window regularly basked in the morning sun with their egg cases, and then took shelter as temperatures rose.

 

At the end of the incubation period, the female constructs a web in which she suspends the egg mass…hence the alternate name, Nursery Web Spider. She stays with the hatchlings for awhile, defending them against predators. My females refused food at this time, but would rush out and “push” crickets that ventured near the web, and would strike at forceps placed in their vicinity.

 

Dark Fishing Spider eggs hatch from July to September. Outdoors, the young hibernate during the winter and become sexually-mature by the following May-June.

 

Hunting and Fishing

Fishing Spiders employ varied hunting techniques. Mine leap at moths, chase down crickets with blinding speed and, most amazing of all, snare guppies and minnows from beneath the water’s surface. In large, planted terrariums, most split their time between lying in ambush on bark slabs and “fishing” at the water’s edge.

 

Anecdotal reports suggest that some Fishing Spiders lure fish to the water’s surface by wiggling a leg in imitation of an insect. I don’t believe this has been definitely documented (please write in if you know otherwise), but the theory is a fascinating one. When hunting at the water’s edge, they anchor the rear 6 legs to a dock, plant or rock and keep the front legs on the water’s surface. Fish, tadpoles or insects that disturb the surface are instantly attacked, with the spiders moving out over the water for several inches if necessary. Flying insects that fall onto the water likely comprise the bulk of their diet in most habitats.

 

Along the Delaware River, I’ve also observed Fishing Spiders standing on the water’s surface, 1-2 feet from the shore, after dark. They are unaffected by a weak flashlight beam, and, much like over-sized water striders, quickly “skate” over to grab insects that I toss in their vicinity. They can also dive and swim below the surface, but I’ve yet to observe this personally.

 

Fishing Spider Care

Caution: Although Fishing Spiders are not considered to be dangerously venomous, they are fast and will not hesitate to bite.  We know little about spider venom, and the possibility of an allergic reaction must be considered….please do not touch any spider with bare hands. Be sure to check your spider’s location before opening the terrarium, as they are incredibly fast.

 

The Terrarium

Dark Fishing Spiders do fine in simple terrariums, but show themselves to their best advantage if provided plenty of space, live plants, upright cork bark slabs and a small pool of water. I use large battery jars or 5-10 gallon aquariums which have a water area created by attaching a panel of glass to the aquarium’s sides with silicone. Complex terrariums allow the spiders to show off their impressive hunting skills, which are most evident when they leaping at moths or flies and snaring fishes.

 

Feeding

Fishing Spiders are quite voracious. Captive females have even been observed feeding upon dead fish, and a photo in the article linked below shows one grabbing a bait minnow from a miscast fishing line (I once accidentally hooked a hawk in Venezuela, but this is the only “fishing for a fishing spider” incident I know of!).

 

Along with guppies and minnows, I offer wild-caught moths, grubs, tree crickets, caterpillars and such when possible, saving crickets and waxworms for the cooler months (wild adults expire in September-October, but captives can live well into January). Hatchlings will take fruit flies, springtails and “meadow plankton”. Small frogs, tadpoles, dragonfly larvae and even slugs have been documented as part of their diet in the wild.

 

Light, Heat and Humidity

I keep my Dark Fishing Spider terrariums very moist, but others have done well in dry set-ups with a daily misting. Hatchlings desiccate easily, and so should be kept in humid enclosures. Normal room temperatures suit them well. I’ve also kept several related species that frequent upland habitats…all have proven to be interesting, hardy captives.

 

While they are not at all shy about feeding by day, Fishing Spiders really come into their own at night. A red reptile night bulb will be a great asset if you wish to observe them after dark.

 

Other Spiders in the Terrarium

Fishing Spider fans will also enjoy the Huntsman or Giant Crab Spider (Heteropoda venatoria), a large, aggressive Asian species that has become established in Florida (of course!) and elsewhere. Jumping, Crevice, Wolf, Crab and Orb-Weaving Spiders, along with countless (literally!) others, also make fascinating terrarium subjects. Please see the articles linked below for information on keeping other spiders, and be sure to post your own thoughts and experiences.

 

 

Further Reading

Jumping Spider Care

Collecting and Keeping Huntsman Spiders

Beyond Webs: Swimming, Spitting and other Spider Hunting Strategies

Plos One Fishing Spider Article

Are Tarantula Bites Dangerous? Sometimes Yes, According to New Study

 

Hi, Frank Indiviglio here.  I’m a herpetologist, zoologist and book author, recently retired  from a career of over 20 years with the Bronx Zoo.  I’ve worked with thousands of tarantulas, in zoos and my own collection, for over 50 years.  In all that time, I’ve never been bitten…mainly because I do not handle them!  Tarantulas certainly adjust to captivity, but they can in no way be “tamed” or “trusted not to bite”…videos and statements to the contrary should be ignored.   Cases involving muscle spasms, chest pain and other severe reactions requiring hospitalizations were reviewed in a recent study – I am aware of similar cases involving colleagues working in the field.  The urticating hairs of New World tarantulas are also a consideration; some years ago, a co-worker of mine required corneal surgery to remove those shed by a Red-Kneed Tarantula.

 

Indian Ornamental Tarantula Bites

In a recent incident reported in the journal Toxicon (an excellent resource for those interested in venom and venomous creatures), a man in Switzerland was bitten on the finger while feeding his pet Indian Ornamental Tarantula, Poecilotheria regalis.  He felt little pain at the time, but experienced hot flashes 2 hours later.  Within 15 hours, he was hospitalized with muscle spasms and chest pain.  He was treated with muscle relaxers, but muscle cramps continued for an additional 3 weeks.

 

Researchers at the Swiss Toxicology Information Center became interested in the case and decided to investigate further.  They turned up 18 additional reports of severe reactions to the bite of the Indian Ornamental Tarantula (a/k/a Indian Ornamental Tree Spider) in their organization’s records and reported in medical journals.  Spider care websites contained anecdotal information about 18 other bites from the same species.

 

Most of the bites were to pet-owners’ hands, but thighs, cheeks and shoulders were also bitten (I imagine this to be the result of foolishly letting spiders wander about the body).  In 58% of the published cases, muscle spasms were suffered by bite victims.  Cramps continued for 1-4 weeks after discharge from the hospital.

 

Tarantula Venom

When corresponding with tarantula owners or training zookeepers, I always stress the fact that spider venoms are quite complex, and we that know very little about those of even commonly-kept species. Antivenin is, in most cases, not available.

 

Also, spider venom may evolve in response to the reactions of prey species, as has been shown to occur among many venomous snakes.  This may affect how bites should be treated, but specific information is scarce.  Venom composition (and, therefore, the necessary treatment) may vary among different populations of the same species…again as occurs in venomous snakes.  Individual sensitivities to tarantula venom, another unstudied subject, must also be considered.

 

As numerous species may be sold under the same common name, and exact identification is often difficult, it is critical that you ascertain the Latin names of any tarantula under your care.

 

Urticating Hairs

North and Latin American tarantulas shed tiny barbed hairs when agitated.  I saw x-ray images of such hairs imbedded in my co-workers eye (please see above).  At the time, I was undergoing a cornea transplant (non-spider related!), and being treated by the same surgeon who had operated on my co-worker.  According to the surgeon, tarantula hairs that work their way into the eye are extremely difficult, and in some cases impossible, to safely remove (in 2009, doctors were unable to remove the hairs of Chilean Rose-haired Tarantula from the eye of a victim in England).

 

So please…enjoy observing and studying tarantulas, but do not touch them.  Please see the articles linked below for information on how to safely keep and transport these fascinating creatures. 

 

Snakes: Venomous Bites and Human Predation

Two surprising studies examining venomous snake bites and snake predation on humans:

 

Venomous Snakes Bite 4.5 Million People Each Year

 

People as Reticulated Python Prey: Study Documents 150 Attacks, 6 deaths in the Philippines

 

 

 

Further Reading

Tarantula Care: Popular Species

Important Supplies for Tarantula Keepers

Interesting Tarantula Facts

Over 900 of the world’s 40,000+ spider species are commonly known as tarantulas (family Theraphosidae).  Among them we find a staggering diversity of sizes, colors, and lifestyles, and many species that make interesting, long-lived pets.  In the early 1980’s, I had the chance to work with the huge collection of a long-time friend, now a noted arachnologist.  Several species in that collection were (and remain) little known in the hobby or zoos.

Today, a wide variety of pet tarantulas, including such long-time favorites as the Mexican Red Leg (Brachypelma), Chilean Rose-Haired (Grammostola), Pink Toed (Avicularia) and the massive Goliath Bird-eating Tarantula (Theraphosa blondii), are now regularly bred by hobbyists.  The key to success with tarantulas is an understanding of their lives in the wild.  Following is an overview; please remember that tarantulas are an extraordinarily diverse group, so details will vary.  Please post below for information on individual species.

Unique Characteristics

While the fangs, or chelicerae, of typical spiders move from side-to-side when grasping prey, those of tarantulas are employed in a downward strike.  Tarantulas are also distinguished from other spiders by their unusual respiratory organs, known as book lungs, and by the presence of 2 claws and adhesive pads on the tips of the legs.  The defensive, urticating hairs of New World species are also unique among spiders (please see “Handling”, below).

One typically sees tarantulas referred to as “primitive” spiders, but they quite successful (please see “Range and Habitat”), and may be the dominant invertebrate predators in many environments.

Females of several species may live into their 30’s, while males rarely exceed 1- 4 years of age. Read More »

Approximately 2,000 scorpion species have been described, but most arachnologists believe that many more await discovery.  Few, however, expected an unknown species to turn up within sight of a major city in the USA.  But that is what happened earlier this year, and the discovery was unusual for other reasons as well.  Another noteworthy new scorpion species surfaced in the Ecuadorean Andes, a little-studied region long suspected of being a diversity hotspot for scorpions.  New Arachnids of all kinds are regularly discovered…please post our own news items and thoughts at the end of this article.

A Unique Scorpion from Arizona’s “Sky Islands”

One never knows where new invertebrates will appear.  In 2000, a new centipede was found in NYC’s Central Park, of all places.  Still, the discovery of a sizable scorpion now known as Vaejovis brysoni was surprising on several levels.  The scorpion was discovered accidentally, in an area of the Santa Catalina Mountains that had been well-studied (6 new species have been found there since 2006), and within sight of Arizona’s capitol city of Tuscan (please see photo).

Also very surprising is the fact that the new scorpion’s habitat is considered by biologists to be a “sky island”.  Sky islands are mountain tops that have become isolated from nearby mountains that contain similar habitats and species.  The valleys between the mountain tops prevent scorpions and other animals from breeding with one another.  Over time, these isolated populations evolve into distinct species.  Oddly, another scorpion of the same genus is already resident on V. brysoni’s “sky island”.  This is the first time that closely related animals have been found on the same mountain in this region.  Learning how 2 similar species survive in close proximity to one another should provide interesting insights into scorpion evolution. Read More »

Emperor Scorpions give birth to live young, and most hobbyists are thrilled when this happens.However, scorpion reproduction breaks many of the “rules” that apply to other pets.For example, a female that has been alone for 14 months may one day be found with 30 tiny white youngsters, or “scorplings”, on her back!I’ve written about scorpion breeding and care in detail elsewhere (please see links below), but thought that an article describing what steps one should take when first discovering youngsters would be useful…especially if your female turns out to be a less-than-perfect mom and begins eating her new creations!Please also be sure to post your questions and concerns below, as scorpion births often take owners by surprise, and I’ll be sure to get right back to you.

Predicting Scorpion Births

In the wild, some Emperor Scorpion populations breed seasonally, while others may reproduce year-round.Captives can mate and give birth during any month of the year. Further complicating our ability to predict births is the fact that females seem able to both store sperm and delay giving birth if conditions are not ideal.Environmental factors such as temperature and stress may also affect the youngsters’ development.Even under ideal conditions, the gestation period may exceed 1 year, although a range of 7 to 10 months is more common.

Read More »