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

I’ve crisscrossed every inch of the American Museum of Natural History – unquestionably the world’s greatest – innumerable times since childhood (and once tried to scale its walls, to capture bats…long story!). Friends working there have kindly taken me behind-the-scenes in several departments, and my 6-year-old nephew is more familiar with the institution than are many adults. But despite having spent a lifetime working with animals at the Bronx Zoo, I am still thrilled each time a new, temporary live animal exhibit opens at AMNH – all are very well done, and perfect for adults and children alike. The current exhibit, Spiders Alive!, is no exception. Although I’ve collected and cared for hundreds of Arachnid species, and my little sidekick has also racked up some impressive experiences, we have visited several times so far, and enjoyed as much as did any novice!

 

The Displays

As with all similar AMNH exhibits, Spiders Alive! features interesting specimens in large, beautifully-designed exhibits along with state-of-the art graphics, huge photos, hands-on interactive opportunities and even a giant anatomically-correct spider sculpture for kids to swarm over (some held back…I guess it was very realistic to them!). Friendly, well-informed volunteers and staff are always on hand to answer questions and help with using the interactive displays. Entry is timed, so there are never crowds or long waits to see or use anything, and visitors are generally well-behaved and polite.

 

One display lets the visitor move a magnifier over a live spider to portray an enlarged view on an overhead screen; my nephew gave that one – and the very nice attending AMNH staffer – a workout! Happily for the budding artists among us (please see photos), spider hideaways and exhibit furnishings are arranged in a way that allows all exhibit specimens to be easily viewed.

 

Learning about Spiders

The species exhibited are used to highlight a number of topics, all of which are well-explained by the graphics. Most obvious is diversity, with arboreal, burrowing, local, exotic, desert-adapted, rainforest-dwelling and other spiders with varying lifestyles being on view now. Other aspects of Arachnid natural history that are illustrated include defense, anatomy, venom, and the uses and structure of silk.

 

The Animals

Following are notes on several of the spiders currently on exhibit. Spider relatives, such as scorpions and the bizarre vinagaroons and tailless whip scorpions, are also featured.

 

Fishing Spiders: these large running spiders are for some reason ignored by spider enthusiasts and zoos alike. The local species here in the NE USA, Dolomedes tenebrosus, is an impressive hunter of small fishes and tadpoles (please see photo of a female with eggs, currently in my collection). My nephew readily tackles snakes exceeding his own length, but when I asked him to swim under a dock and capture this spider, he quickly replied “No way, man”!

 

Goliath Bird-Eating Tarantula: perhaps the world’s largest spider, this species is a favorite of private and professional spider keepers. Field reports indicate that they prey upon small rodents, snakes, frogs, lizards and other vertebrates in addition to insects. Certainly, those under my care startled me with their voracious appetites.

 

Ornamental Tarantulas: Beautifully-colored but rather aggressive – and very fast moving, I can assure you! – these SE Asian spiders are highly arboreal.

 

Black Widow and Brown Recluse: known to many folks here in the USA, the habits of these two potentially-dangerous spiders are well-explained.

 

Orb Weavers: Several species are on view, each in the center of a large, intricately-woven web.

 

Funnel Web Spider: the species displayed is not the highly venomous Australian spider of the same name but rather a harmless and very common US native (Agelenopsis sp.). I’ve often kept these interesting spiders…but until now believed I was the only one to do so! Vertical “trip lines” knock flying insects onto a sheet-like web, whereupon the spider rushes out and drags its hapless victim down the funnel-shaped retreat. Always happy to demonstrate their talents to onlookers, I find funnel web spiders to be fascinating captives.

 

Several of the other species featured are well-known or common, but their habits are revealed in a way that cannot help but cause one to appreciate these maligned but fascinating little beasts. Some others that you can see include Mexican Red-Kneed Tarantulas, House Spiders, Trap-Door Spiders and Wolf Spiders.

 

 

Further Reading

Keeping the Fishing Spider

Spider Hunting Methods – Beyond Webs

 Spiders Alive!

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

Among the world’s 900+ tarantula species (Family Theraphosidae) we find spiders of every conceivable size, description and lifestyle, some of which make interesting, long-lived pets.  I had the chance to work with many during my zoo career, and most of the supplies that I relied upon are now readily available to hobbyists.  Whether you are just starting out or looking to add additional species to your collection, the following information will assist in your decision.  Please be sure to post any questions or observations about pet tarantulas below. 

Housing

Setting up the Terrarium

Tarantulas are best kept in screen-covered aquariums, reptile cages or plastic terrariums.  “Extra high” styles are best for Pink-Toed Tarantulas and other arboreal species.  Be sure to use cage clips on the cover, as tarantulas can climb glass and are incredibly strong.  A 10-15 gallon aquarium is adequate for all but the largest individuals.

All tarantulas require a dark hiding spot.  Burrowing species such as the Goliath Bird-Eating Spider will dig their own caves if provided deep substrate. Sri Lankan Ornamental Tarantulas and other arboreal species will utilize the underside of an upright piece of cork bark.  Most also accept inverted flower pots and plastic reptile caves. Read More »

Invertebrate enthusiasts have learned to expect the discovery of fantastic new species on a regular basis.  But even old timers such as I were shocked by some that came to light this past year. Large, claw-bearing Cave Robber Spiders, giant bio-luminescent roaches, brilliant arboreal tarantulas, neon-colored freshwater crabs, dive-bombing wasps…the list boggles the mind.  Today I’ll highlight a few that have entranced me; please post your own favorites (whether covered here or not) below.

Cave Robber Spider, Trogloraptor marchingtoni

The Cave Robber Spider, arguably 2012’s most “otherworldly” discovery, turned up in a place not known for hiding unseen species – southwestern Oregon.  In fact, not a single new spider has been described in the USA in the past 130 years.  Read More »

As a bug-hunting child, I was once startled to come upon a housefly that appeared to be walking on its hind legs.  Closer inspection revealed that the unfortunate insect was being carried in a head-up position by a Jumping Spider.  I was aware that a variety of these brilliantly-colored little beasts inhabited my Bronx neighborhood, and became interested in how they managed to capture such elusive prey without a web. I began reading and collecting, and was soon fascinated by their keen eyesight and cat-like stalking techniques.  They would follow my finger, leap on a feathers pulled by a string, and even display to a mirrors.

I’ve recently learned that biologists are showing videos to Jumping Spiders in an attempt to learn more about their remarkable eyes (which allow for forward, backward, an sideways vision simultaneously), and that a new ant-mimicking Jumping Spider with enormous fangs has turned up in Borneo.  I’ll highlight this new information below, and review their natural history and captive care.

A 360 Degree Field of Vision

Animals that are on the menus of other creatures generally have eyes set well back and to the sides of their heads.  This arrangement gives mice, deer and others a wide field of vision, with the only bind spots being well to their rear.  Predators, such as foxes and hawks, usually have forward-facing eyes, to allow for accurate focusing on prey. Read More »